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1 .H0 "Discussion
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2 .P
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3 This main chapter discusses the practical work done in the mmh project.
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4 It is structured along the goals to achieve.
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5 The concrete work done
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6 is described in the examples of how the general goals were achieved.
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7 The discussion compares the current version of mmh with the state of
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8 nmh just before the mmh project started, i.e. Fall 2011.
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9 Current changes of nmh will be mentioned only as side notes.
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10 .\" XXX where do I discuss the parallel development of nmh?
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11
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12
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13
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14 .\" --------------------------------------------------------------
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15 .H1 "Streamlining
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16
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17 .P
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18 MH had been considered an all-in-one system for mail handling.
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19 The community around nmh has a similar understanding.
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20 In fundamental difference, mmh shall be a MUA only.
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21 I believe that the development of all-in-one mail systems is obsolete.
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22 Today, email is too complex to be fully covered by single projects.
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23 Such a project won't be able to excel in all aspects.
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24 Instead, the aspects of email should be covered by multiple projects,
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25 which then can be combined to form a complete system.
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26 Excellent implementations for the various aspects of email exist already.
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27 Just to name three examples: Postfix is a specialized MTA,
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28 .\" XXX homepages verlinken
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29 Procmail is a specialized MDA, and Fetchmail is a specialized MRA.
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30 I believe that it is best to use such specialized tools instead of
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31 providing the same function again as a side-component in the project.
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32 .P
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33 Doing something well, requires to focus on a small set of specific aspects.
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34 Under the assumption that focused development produces better results
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35 in the particular area, specialized projects will be superior
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36 in their field of focus.
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37 Hence, all-in-one mail system projects \(en no matter if monolithic
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38 or modular \(en will never be the best choice in any of the fields.
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39 Even in providing the best consistent all-in-one system they are likely
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40 to be beaten by projects that focus only on integrating existing mail
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41 components to a homogeneous system.
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42 .P
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43 The limiting resource in Free Software community development
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44 is usually man power.
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45 If the development power is spread over a large development area,
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46 it becomes even more difficult to compete with the specialists in the
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47 various fields.
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48 The concrete situation for MH-based mail systems is even tougher,
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49 given the small and aged community, including both developers and users,
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50 it has.
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51 .P
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52 In consequence, I believe that the available development resources
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53 should focus on the point where MH is most unique.
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54 This is clearly the user interface \(en the MUA.
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55 Peripheral parts should be removed to streamline mmh for the MUA task.
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56
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57
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58 .H2 "Mail Transfer Facilities
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59 .Id mail-transfer-facilities
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60 .P
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61 In contrast to nmh, which also provides mail submission and mail retrieval
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62 agents, mmh is a MUA only.
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63 This general difference initiated the development of mmh.
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64 Removing the mail transfer facilities had been the first work task
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65 in the mmh project.
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66 .P
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67 Focusing on one mail agent role only is motivated by Eric Allman's
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68 experience with Sendmail.
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69 He identified the limitation of Sendmail to the MTA task as one reason for
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70 its success:
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71 .[ [
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72 costales sendmail
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73 .], p. xviii]
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74 .QS
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75 Second, I limited myself to the routing function \(en
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76 I wouldn't write user agents or delivery back-ends.
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77 This was a departure of the dominant through of the time,
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78 in which routing logic, local delivery, and often the network code
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79 were incorporated directly into the user agents.
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80 .QE
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81 .P
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82 In nmh, the Mail Submission Agent (MSA) is called
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83 \fIMessage Transfer Service\fP (MTS).
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84 This facility, implemented by the
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85 .Pn post
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86 command, established network connections and spoke SMTP to submit
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87 messages to be relayed to the outside world.
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88 The changes in email demanded changes in this part of nmh too.
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89 Encryption and authentication for network connections
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90 needed to be supported, hence TLS and SASL were introduced into nmh.
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91 This added complexity to nmh without improving it in its core functions.
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92 Also, keeping up with recent developments in the field of
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93 mail transfer requires development power and specialists.
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94 In mmh this whole facility was simply cut off.
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95 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
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96 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
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97 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
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98 Instead, mmh depends on an external MSA.
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99 The only outgoing interface available to mmh is the
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100 .Pn sendmail
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101 command, which almost any MSA provides.
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102 If not, a wrapper program can be written.
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103 It must read the message from the standard input, extract the
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104 recipient addresses from the message header, and hand the message
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105 over to the MSA.
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106 For example, a wrapper script for qmail would be:
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107 .VS
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108 #!/bin/sh
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109 exec qmail-inject # ignore command line arguments
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110 VE
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111 The requirement to parse the recipient addresses out of the message header
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112 is likely to be removed in the future.
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113 Then mmh would give the recipient addresses as command line arguments.
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114 This appears to be the better interface.
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115 .\" XXX implement it
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116 .P
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117 To retrieve mail, the
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118 .Pn inc
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119 command acted as Mail Retrieval Agent (MRA).
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120 It established network connections
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121 and spoke POP3 to retrieve mail from remote servers.
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122 As with mail submission, the network connections required encryption and
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123 authentication, thus TLS and SASL were added.
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124 Support for message retrieval through IMAP will become necessary
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125 to be added soon, too, and likewise for any other changes in mail transfer.
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126 Not so for mmh because it has dropped the support for retrieving mail
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127 from remote locations.
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128 .Ci ab7b48411962d26439f92f35ed084d3d6275459c
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129 Instead, it depends on an external tool to cover this task.
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130 In mmh, two paths exist for messages to enter mmh's mail storage:
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131 (1) Mail can be incorporated with
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132 .Pn inc
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133 from the system maildrop, or (2) with
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134 .Pn rcvstore
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135 by reading them, one at a time, from the standard input.
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136 .P
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137 With the removal of the MSA and MRA, mmh converted from an all-in-one
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138 mail system to being a MUA only.
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139 Now, of course, mmh depends on third-party software.
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140 An external MSA is required to transfer mail to the outside world;
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141 an external MRA is required to retrieve mail from remote machines.
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142 There exist excellent implementations of such software,
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143 which likely are superior than the internal version.
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144 Additionally, the best suiting programs can be freely chosen.
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145 .P
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146 As it had already been possible to use an external MSA or MRA,
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147 why not keep the internal version for convenience?
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148 .\" XXX ueberleitung
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149 The question whether there is sense in having a fall-back pager in all
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150 the command line tools, for the cases when
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151 .Pn more
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152 or
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153 .Pn less
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154 aren't available, appears to be ridiculous.
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155 Of course, MSAs and MRAs are more complex than text pagers
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156 and not necessarily available but still the concept of orthogonal
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157 design holds: ``Write programs that do one thing and do it well.''
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158 .[
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159 mcilroy unix phil
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160 p. 53
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161 .]
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162 .[
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163 mcilroy bstj foreword
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164 .]
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165 Here, this part of the Unix philosophy was applied not only
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166 to the programs but to the project itself.
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167 In other words:
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168 ``Develop projects that focus on one thing and do it well.''
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169 Projects grown complex should be split for the same reasons programs grown
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170 complex should be split.
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171 If it is conceptionally more elegant to have the MSA and MRA as
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172 separate projects then they should be separated.
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173 This is the case here, in my opinion.
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174 The RFCs propose this separation by clearly distinguishing the different
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175 mail handling tasks.
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176 .[
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177 rfc 821
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178 .]
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179 The small interfaces between the mail agents support the separation.
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180 .P
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181 In the beginning, email had been small and simple.
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182 At that time,
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183 .Pn /bin/mail
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184 had covered anything there was to email and still had been small
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185 and simple.
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186 Later, the essential complexity of email increased.
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187 (Essential complexity is the complexity defined by the problem itself.\0
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188 .[[
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189 brooks no silver bullet
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190 .]])
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191 Email systems reacted to this change: They grew.
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192 RFCs started to introduce the concept of mail agents to separate the
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193 various tasks because they became more extensive and new tasks appeared.
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194 As the mail systems grew even more, parts were split off.
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195 In nmh, for instance, the POP server, which was included in the original
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196 MH, was removed.
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197 Now is the time to go one step further and split the MSA and MRA off, too.
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198 Not only does this decrease the code size of the project,
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199 but, more important, it unburdens mmh of the whole field of
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200 message transfer with all its implications for the project.
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201 There is no more need to concern with changes in network transfer.
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202 This independence is received by depending on an external program
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203 that covers the field.
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204 Today, this is a reasonable exchange.
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205 .P
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206 .\" XXX ueberleitung ???
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207 Functionality can be added in three different ways:
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208 .BU
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209 Implementing the function originally in the project.
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210 .BU
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211 Depending on a library that provides the function.
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212 .BU
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213 Depending on a program that provides the function.
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214 .P
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215 .\" XXX Rework sentence
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216 While adding the function originally to the project increases the
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217 code size most and requires most maintenance and development work,
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218 it makes the project most independent of other software.
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219 Using libraries or external programs require less maintenance work
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220 but introduces dependencies on external software.
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221 Programs have the smallest interfaces and provide the best separation
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222 but possibly limit the information exchange.
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223 External libraries are stronger connected than external programs,
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224 thus information can be exchanged more flexible.
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225 Adding code to a project increases maintenance work.
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226 .\" XXX ref
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227 Implementing complex functions in the project itself adds
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228 a lot of code.
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229 This should be avoided if possible.
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230 Hence, the dependencies only change in kind, not in their existence.
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231 In mmh, library dependencies on
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232 .Pn libsasl2
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233 and
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234 .Pn libcrypto /\c
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235 .Pn libssl
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236 were traded against program dependencies on an MSA and an MRA.
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237 This also meant trading build-time dependencies against run-time
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238 dependencies.
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239 Besides program dependencies providing the stronger separation
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240 and being more flexible, they also allowed
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241 over 6\|000 lines of code to be removed from mmh.
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242 This made mmh's code base about 12\|% smaller.
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243 Reducing the project's code size by such an amount without actually
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244 losing functionality is a convincing argument.
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245 Actually, as external MSAs and MRAs are likely superior to the
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246 project's internal versions, the common user even gains functionality.
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247 .P
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248 Users of MH should not have problems to set up an external MSA and MRA.
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249 Also, the popular MSAs and MRAs have large communities and a lot
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250 of documentation available.
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251 Choices for MSAs range from full-featured MTAs like
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252 .\" XXX refs
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253 .I Postfix
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254 over mid-size MTAs like
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255 .I masqmail
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256 and
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257 .I dma
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258 to small forwarders like
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259 .I ssmtp
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260 and
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261 .I nullmailer .
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262 Choices for MRAs include
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263 .I fetchmail ,
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264 .I getmail ,
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265 .I mpop
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266 and
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267 .I fdm .
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268
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269
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270 .H2 "Non-MUA Tools
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271 .P
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272 One goal of mmh is to remove the tools that are not part of the MUA's task.
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273 Further more, any tools that don't improve the MUA's job significantly
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274 should be removed.
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275 Loosely related and rarely used tools distract from the lean appearance.
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276 They require maintenance work without adding much to the core task.
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277 By removing these tools, the project shall become more streamlined
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278 and focused.
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279 In mmh the following tools are not available anymore:
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280 .BU
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281 .Pn conflict
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282 was removed
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283 .Ci 8b235097cbd11d728c07b966cf131aa7133ce5a9
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284 because it is a mail system maintenance tool that is not MUA-related.
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285 It even checked
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286 .Fn /etc/passwd
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287 and
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288 .Fn /etc/group
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289 for consistency, which is completely unrelated to email.
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290 A tool like
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291 .Pn conflict
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292 is surely useful, but it should not be shipped with mmh.
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293 .\" XXX historic reasons?
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294 .BU
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295 .Pn rcvtty
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296 was removed
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297 .Ci 14767c94b3827be7c867196467ed7aea5f6f49b0
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298 because its use case of writing to the user's terminal
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299 on receival of mail is obsolete.
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300 If users like to be informed of new mail, the shell's
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301 .Ev MAILPATH
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302 variable or graphical notifications are technically more appealing.
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303 Writing directly to terminals is hardly ever wanted today.
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304 If though one wants to have it this way, the standard tool
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305 .Pn write
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meillo@58
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306 can be used in a way similar to:
|
|
meillo@82
|
307 .VS
|
|
meillo@58
|
308 scan -file - | write `id -un`
|
|
meillo@82
|
309 VE
|
|
meillo@62
|
310 .BU
|
|
meillo@58
|
311 .Pn viamail
|
|
meillo@159
|
312 .\" XXX was macht viamail
|
|
meillo@87
|
313 was removed
|
|
meillo@87
|
314 .Ci eda72d6a7a7c20ff123043fb7f19c509ea01f932
|
|
meillo@87
|
315 when the new attachment system was activated, because
|
|
meillo@58
|
316 .Pn forw
|
|
meillo@76
|
317 could then cover the task itself.
|
|
meillo@62
|
318 The program
|
|
meillo@58
|
319 .Pn sendfiles
|
|
meillo@62
|
320 was rewritten as a shell script wrapper around
|
|
meillo@58
|
321 .Pn forw .
|
|
meillo@76
|
322 .Ci 0e82199cf3c991a173e0ac8aa776efdb3ded61e6
|
|
meillo@62
|
323 .BU
|
|
meillo@58
|
324 .Pn msgchk
|
|
meillo@159
|
325 .\" XXX was macht msgchk
|
|
meillo@87
|
326 was removed
|
|
meillo@87
|
327 .Ci bb9360ead7eb7a3fedcce2eeedfc660014e41dbe ,
|
|
meillo@87
|
328 because it lost its use case when POP support was removed.
|
|
meillo@76
|
329 A call to
|
|
meillo@58
|
330 .Pn msgchk
|
|
meillo@87
|
331 provided hardly more information than:
|
|
meillo@82
|
332 .VS
|
|
meillo@58
|
333 ls -l /var/mail/meillo
|
|
meillo@82
|
334 VE
|
|
meillo@100
|
335 It did distinguish between old and new mail, but
|
|
meillo@100
|
336 this detail information can be retrieved with
|
|
meillo@76
|
337 .Pn stat (1),
|
|
meillo@62
|
338 too.
|
|
meillo@100
|
339 A small shell script could be written to print the information
|
|
meillo@76
|
340 in a similar way, if truly necessary.
|
|
meillo@76
|
341 As mmh's
|
|
meillo@76
|
342 .Pn inc
|
|
meillo@87
|
343 only incorporates mail from the user's local maildrop,
|
|
meillo@62
|
344 and thus no data transfers over slow networks are involved,
|
|
meillo@76
|
345 there's hardly any need to check for new mail before incorporating it.
|
|
meillo@62
|
346 .BU
|
|
meillo@58
|
347 .Pn msh
|
|
meillo@87
|
348 was removed
|
|
meillo@76
|
349 .Ci 916690191222433a6923a4be54b0d8f6ac01bd02
|
|
meillo@87
|
350 because the tool was in conflict with the philosophy of MH.
|
|
meillo@76
|
351 It provided an interactive shell to access the features of MH,
|
|
meillo@159
|
352 but it wasn't just a shell tailored to the needs of mail handling.
|
|
meillo@76
|
353 Instead it was one large program that had several MH tools built in.
|
|
meillo@76
|
354 This conflicts with the major feature of MH of being a tool chest.
|
|
meillo@76
|
355 .Pn msh 's
|
|
meillo@159
|
356 main use case had been accessing Bulletin Boards, which have ceased to
|
|
meillo@62
|
357 be popular.
|
|
meillo@62
|
358 .P
|
|
meillo@62
|
359 Removing
|
|
meillo@58
|
360 .Pn msh ,
|
|
meillo@76
|
361 together with the truly archaic code relicts
|
|
meillo@58
|
362 .Pn vmh
|
|
meillo@58
|
363 and
|
|
meillo@58
|
364 .Pn wmh ,
|
|
meillo@62
|
365 saved more than 7\|000 lines of C code \(en
|
|
meillo@66
|
366 about 15\|% of the project's original source code amount.
|
|
meillo@100
|
367 Having less code \(en with equal readability, of course \(en
|
|
meillo@76
|
368 for the same functionality is an advantage.
|
|
meillo@63
|
369 Less code means less bugs and less maintenance work.
|
|
meillo@76
|
370 As
|
|
meillo@63
|
371 .Pn rcvtty
|
|
meillo@63
|
372 and
|
|
meillo@63
|
373 .Pn msgchk
|
|
meillo@87
|
374 are assumed to be rarely used and can be implemented in different ways,
|
|
meillo@87
|
375 why should one keep them?
|
|
meillo@125
|
376 Removing them streamlines mmh.
|
|
meillo@63
|
377 .Pn viamail 's
|
|
meillo@63
|
378 use case is now partly obsolete and partly covered by
|
|
meillo@63
|
379 .Pn forw ,
|
|
meillo@76
|
380 hence there's no reason to still maintain it.
|
|
meillo@63
|
381 .Pn conflict
|
|
meillo@76
|
382 is not related to the mail client, and
|
|
meillo@63
|
383 .Pn msh
|
|
meillo@63
|
384 conflicts with the basic concept of MH.
|
|
meillo@76
|
385 Theses two tools might still be useful, but they should not be part of mmh.
|
|
meillo@63
|
386 .P
|
|
meillo@76
|
387 Finally, there's
|
|
meillo@76
|
388 .Pn slocal .
|
|
meillo@76
|
389 .Pn slocal
|
|
meillo@76
|
390 is an MDA and thus not directly MUA-related.
|
|
meillo@100
|
391 It should be removed from mmh, because including it conflicts with
|
|
meillo@100
|
392 the idea that mmh is a MUA only.
|
|
meillo@100
|
393 .Pn slocal
|
|
meillo@100
|
394 should rather become a separate project.
|
|
meillo@87
|
395 However,
|
|
meillo@76
|
396 .Pn slocal
|
|
meillo@76
|
397 provides rule-based processing of messages, like filing them into
|
|
meillo@76
|
398 different folders, which is otherwise not available in mmh.
|
|
meillo@87
|
399 Although
|
|
meillo@76
|
400 .Pn slocal
|
|
meillo@87
|
401 does neither pull in dependencies nor does it include a separate
|
|
meillo@154
|
402 technical area (cf. Sec.
|
|
meillo@154
|
403 .Cf mail-transfer-facilities ),
|
|
meillo@154
|
404 still,
|
|
meillo@100
|
405 it accounts for about 1\|000 lines of code that need to be maintained.
|
|
meillo@76
|
406 As
|
|
meillo@76
|
407 .Pn slocal
|
|
meillo@76
|
408 is almost self-standing, it should be split off into a separate project.
|
|
meillo@76
|
409 This would cut the strong connection between the MUA mmh and the MDA
|
|
meillo@76
|
410 .Pn slocal .
|
|
meillo@87
|
411 For anyone not using MH,
|
|
meillo@87
|
412 .Pn slocal
|
|
meillo@87
|
413 would become yet another independent MDA, like
|
|
meillo@87
|
414 .I procmail .
|
|
meillo@100
|
415 Then
|
|
meillo@87
|
416 .Pn slocal
|
|
meillo@100
|
417 could be installed without the complete MH system.
|
|
meillo@76
|
418 Likewise, mmh users could decide to use
|
|
meillo@76
|
419 .I procmail
|
|
meillo@87
|
420 without having a second, unused MDA,
|
|
meillo@87
|
421 .Pn slocal ,
|
|
meillo@76
|
422 installed.
|
|
meillo@100
|
423 That appears to be conceptionally the best solution.
|
|
meillo@76
|
424 Yet,
|
|
meillo@76
|
425 .Pn slocal
|
|
meillo@87
|
426 is not split off.
|
|
meillo@100
|
427 I defer the decision over
|
|
meillo@78
|
428 .Pn slocal
|
|
meillo@100
|
429 in need for deeper investigation.
|
|
meillo@100
|
430 In the meanwhile, it remains part of mmh.
|
|
meillo@159
|
431 However, its continued existence is not significant because
|
|
meillo@100
|
432 .Pn slocal
|
|
meillo@100
|
433 is unrelated to the rest of the project.
|
|
meillo@0
|
434
|
|
meillo@58
|
435
|
|
meillo@133
|
436
|
|
meillo@134
|
437 .H2 "Displaying Messages
|
|
meillo@155
|
438 .Id mhshow
|
|
meillo@131
|
439 .P
|
|
meillo@133
|
440 Since the very beginning, already in the first concept paper,
|
|
meillo@159
|
441 .\" XXX ref!!!
|
|
meillo@58
|
442 .Pn show
|
|
meillo@62
|
443 had been MH's message display program.
|
|
meillo@58
|
444 .Pn show
|
|
meillo@76
|
445 mapped message numbers and sequences to files and invoked
|
|
meillo@58
|
446 .Pn mhl
|
|
meillo@89
|
447 to have the files formatted.
|
|
meillo@88
|
448 With MIME, this approach wasn't sufficient anymore.
|
|
meillo@100
|
449 MIME messages can consist of multiple parts. Some parts are not
|
|
meillo@100
|
450 directly displayable and text content might be encoded in
|
|
meillo@58
|
451 foreign charsets.
|
|
meillo@58
|
452 .Pn show 's
|
|
meillo@76
|
453 understanding of messages and
|
|
meillo@58
|
454 .Pn mhl 's
|
|
meillo@88
|
455 display capabilities couldn't cope with the task any longer.
|
|
meillo@62
|
456 .P
|
|
meillo@88
|
457 Instead of extending these tools, additional tools were written from
|
|
meillo@88
|
458 scratch and added to the MH tool chest.
|
|
meillo@88
|
459 Doing so is encouraged by the tool chest approach.
|
|
meillo@88
|
460 Modular design is a great advantage for extending a system,
|
|
meillo@88
|
461 as new tools can be added without interfering with existing ones.
|
|
meillo@62
|
462 First, the new MIME features were added in form of the single program
|
|
meillo@58
|
463 .Pn mhn .
|
|
meillo@58
|
464 The command
|
|
meillo@82
|
465 .Cl "mhn -show 42
|
|
meillo@58
|
466 would show the MIME message numbered 42.
|
|
meillo@58
|
467 With the 1.0 release of nmh in February 1999, Richard Coleman finished
|
|
meillo@58
|
468 the split of
|
|
meillo@58
|
469 .Pn mhn
|
|
meillo@88
|
470 into a set of specialized tools, which together covered the
|
|
meillo@88
|
471 multiple aspects of MIME.
|
|
meillo@88
|
472 One of them was
|
|
meillo@69
|
473 .Pn mhshow ,
|
|
meillo@88
|
474 which replaced
|
|
meillo@88
|
475 .Cl "mhn -show" .
|
|
meillo@88
|
476 It was capable of displaying MIME messages appropriately.
|
|
meillo@62
|
477 .P
|
|
meillo@88
|
478 From then on, two message display tools were part of nmh,
|
|
meillo@76
|
479 .Pn show
|
|
meillo@76
|
480 and
|
|
meillo@76
|
481 .Pn mhshow .
|
|
meillo@88
|
482 To ease the life of users,
|
|
meillo@69
|
483 .Pn show
|
|
meillo@69
|
484 was extended to automatically hand the job over to
|
|
meillo@69
|
485 .Pn mhshow
|
|
meillo@69
|
486 if displaying the message would be beyond
|
|
meillo@69
|
487 .Pn show 's
|
|
meillo@69
|
488 abilities.
|
|
meillo@88
|
489 In consequence, the user would simply invoke
|
|
meillo@69
|
490 .Pn show
|
|
meillo@69
|
491 (possibly through
|
|
meillo@69
|
492 .Pn next
|
|
meillo@69
|
493 or
|
|
meillo@69
|
494 .Pn prev )
|
|
meillo@69
|
495 and get the message printed with either
|
|
meillo@69
|
496 .Pn show
|
|
meillo@69
|
497 or
|
|
meillo@69
|
498 .Pn mhshow ,
|
|
meillo@69
|
499 whatever was more appropriate.
|
|
meillo@69
|
500 .P
|
|
meillo@69
|
501 Having two similar tools for essentially the same task is redundant.
|
|
meillo@88
|
502 Usually,
|
|
meillo@88
|
503 users wouldn't distinguish between
|
|
meillo@88
|
504 .Pn show
|
|
meillo@88
|
505 and
|
|
meillo@88
|
506 .Pn mhshow
|
|
meillo@88
|
507 in their daily mail reading.
|
|
meillo@88
|
508 Having two separate display programs was therefore mainly unnecessary
|
|
meillo@88
|
509 from a user's point of view.
|
|
meillo@88
|
510 Besides, the development of both programs needed to be in sync,
|
|
meillo@76
|
511 to ensure that the programs behaved in a similar way,
|
|
meillo@76
|
512 because they were used like a single tool.
|
|
meillo@76
|
513 Different behavior would have surprised the user.
|
|
meillo@69
|
514 .P
|
|
meillo@69
|
515 Today, non-MIME messages are rather seen to be a special case of
|
|
meillo@100
|
516 MIME messages, although it is the other way round.
|
|
meillo@69
|
517 As
|
|
meillo@69
|
518 .Pn mhshow
|
|
meillo@159
|
519 had already been able to display non-MIME messages, it appeared natural
|
|
meillo@69
|
520 to drop
|
|
meillo@69
|
521 .Pn show
|
|
meillo@69
|
522 in favor of using
|
|
meillo@69
|
523 .Pn mhshow
|
|
meillo@69
|
524 exclusively.
|
|
meillo@88
|
525 .Ci 4c1efddfd499300c7e74263e57d8aa137e84c853
|
|
meillo@88
|
526 Removing
|
|
meillo@88
|
527 .Pn show
|
|
meillo@88
|
528 is no loss in function, because functionally
|
|
meillo@88
|
529 .Pn mhshow
|
|
meillo@88
|
530 covers it completely.
|
|
meillo@88
|
531 The old behavior of
|
|
meillo@88
|
532 .Pn show
|
|
meillo@88
|
533 can still be emulated with the simple command line:
|
|
meillo@88
|
534 .VS
|
|
meillo@88
|
535 mhl `mhpath c`
|
|
meillo@88
|
536 VE
|
|
meillo@88
|
537 .P
|
|
meillo@76
|
538 For convenience,
|
|
meillo@76
|
539 .Pn mhshow
|
|
meillo@88
|
540 was renamed to
|
|
meillo@88
|
541 .Pn show
|
|
meillo@88
|
542 after
|
|
meillo@88
|
543 .Pn show
|
|
meillo@88
|
544 was gone.
|
|
meillo@88
|
545 It is clear that such a rename may confuse future developers when
|
|
meillo@88
|
546 trying to understand the history.
|
|
meillo@88
|
547 Nevertheless, I consider the convenience on the user's side,
|
|
meillo@88
|
548 to call
|
|
meillo@88
|
549 .Pn show
|
|
meillo@88
|
550 when they want a message to be displayed, to outweigh the inconvenience
|
|
meillo@88
|
551 on the developer's side when understanding the project history.
|
|
meillo@69
|
552 .P
|
|
meillo@88
|
553 To prepare for the transition,
|
|
meillo@69
|
554 .Pn mhshow
|
|
meillo@69
|
555 was reworked to behave more like
|
|
meillo@69
|
556 .Pn show
|
|
meillo@69
|
557 first.
|
|
meillo@154
|
558 (cf. Sec.
|
|
meillo@154
|
559 .Cf mhshow )
|
|
meillo@88
|
560 Once the tools behaved more alike, the replacing appeared to be
|
|
meillo@88
|
561 even more natural.
|
|
meillo@88
|
562 Today, mmh's new
|
|
meillo@69
|
563 .Pn show
|
|
meillo@159
|
564 has become the one single message display program once more,
|
|
meillo@159
|
565 with the difference
|
|
meillo@88
|
566 that today it handles MIME messages as well as non-MIME messages.
|
|
meillo@88
|
567 The outcome of the transition is one program less to maintain,
|
|
meillo@88
|
568 no second display program for users to deal with,
|
|
meillo@88
|
569 and less system complexity.
|
|
meillo@69
|
570 .P
|
|
meillo@88
|
571 Still, removing the old
|
|
meillo@69
|
572 .Pn show
|
|
meillo@88
|
573 hurts in one regard: It had been such a simple program.
|
|
meillo@159
|
574 Its lean elegance is missing from the new
|
|
meillo@159
|
575 .Pn show ,
|
|
meillo@159
|
576 .\" XXX
|
|
meillo@159
|
577 however there is no alternative;
|
|
meillo@159
|
578 supporting MIME demands higher essential complexity.
|
|
meillo@58
|
579
|
|
meillo@134
|
580 .ig
|
|
meillo@134
|
581 XXX
|
|
meillo@134
|
582 Consider including text on scan listings here
|
|
meillo@58
|
583
|
|
meillo@134
|
584 Scan listings shall not contain body content. Hence, removed this feature.
|
|
meillo@134
|
585 Scan listings shall operator on message headers and non-message information
|
|
meillo@134
|
586 only. Displaying the beginning of the body complicates everything too much.
|
|
meillo@134
|
587 That's no surprise, because it's something completely different. If you
|
|
meillo@134
|
588 want to examine the body, then use show(1)/mhshow(1).
|
|
meillo@134
|
589 Changed the default scan formats accordingly.
|
|
meillo@134
|
590 .Ci 70b2643e0da8485174480c644ad9785c84f5bff4
|
|
meillo@134
|
591 ..
|
|
meillo@131
|
592
|
|
meillo@131
|
593
|
|
meillo@131
|
594
|
|
meillo@133
|
595
|
|
meillo@100
|
596 .H2 "Configure Options
|
|
meillo@58
|
597 .P
|
|
meillo@76
|
598 Customization is a double-edged sword.
|
|
meillo@76
|
599 It allows better suiting setups, but not for free.
|
|
meillo@76
|
600 There is the cost of code complexity to be able to customize.
|
|
meillo@76
|
601 There is the cost of less tested setups, because there are
|
|
meillo@72
|
602 more possible setups and especially corner-cases.
|
|
meillo@159
|
603 Additionally, there is the cost of choice itself.
|
|
meillo@76
|
604 The code complexity directly affects the developers.
|
|
meillo@72
|
605 Less tested code affects both, users and developers.
|
|
meillo@159
|
606 The problem of choice affects the users, for once by having to choose,
|
|
meillo@159
|
607 but also by more complex interfaces that require more documentation.
|
|
meillo@159
|
608 Whenever options add few advantages but increase the complexity of the
|
|
meillo@159
|
609 system, they should be considered for removal.
|
|
meillo@72
|
610 I have reduced the number of project-specific configure options from
|
|
meillo@72
|
611 fifteen to three.
|
|
meillo@74
|
612
|
|
meillo@76
|
613 .U3 "Mail Transfer Facilities
|
|
meillo@74
|
614 .P
|
|
meillo@85
|
615 With the removal of the mail transfer facilities five configure
|
|
meillo@85
|
616 options vanished:
|
|
meillo@85
|
617 .P
|
|
meillo@85
|
618 The switches
|
|
meillo@85
|
619 .Sw --with-tls
|
|
meillo@85
|
620 and
|
|
meillo@85
|
621 .Sw --with-cyrus-sasl
|
|
meillo@89
|
622 had activated the support for transfer encryption and authentication.
|
|
meillo@159
|
623 .\" XXX cf
|
|
meillo@159
|
624 .\" XXX gruende kurz wiederholen
|
|
meillo@85
|
625 This is not needed anymore.
|
|
meillo@85
|
626 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
|
|
meillo@85
|
627 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
|
|
meillo@85
|
628 .P
|
|
meillo@159
|
629 .\" XXX cf
|
|
meillo@159
|
630 .\" XXX ``For the same reason ...''
|
|
meillo@85
|
631 The configure switch
|
|
meillo@85
|
632 .Sw --enable-pop
|
|
meillo@85
|
633 activated the message retrieval facility.
|
|
meillo@85
|
634 The code area that would be conditionally compiled in for TLS and SASL
|
|
meillo@85
|
635 support had been small.
|
|
meillo@85
|
636 The conditionally compiled code area for POP support had been much larger.
|
|
meillo@85
|
637 Whereas the code base changes would only slightly change on toggling
|
|
meillo@85
|
638 TLS or SASL support, it changed much on toggling POP support.
|
|
meillo@85
|
639 The changes in the code base could hardly be overviewed.
|
|
meillo@159
|
640 By having POP support togglable, a second code base had been created,
|
|
meillo@85
|
641 one that needed to be tested.
|
|
meillo@85
|
642 This situation is basically similar for the conditional TLS and SASL
|
|
meillo@85
|
643 code, but there the changes are minor and can yet be overviewed.
|
|
meillo@85
|
644 Still, conditional compilation of a code base creates variations
|
|
meillo@85
|
645 of the original program.
|
|
meillo@85
|
646 More variations require more testing and maintenance work.
|
|
meillo@85
|
647 .P
|
|
meillo@85
|
648 Two other options only specified default configuration values:
|
|
meillo@100
|
649 .Sw --with-mts
|
|
meillo@100
|
650 defined the default transport service, either
|
|
meillo@100
|
651 .Ar smtp
|
|
meillo@100
|
652 or
|
|
meillo@100
|
653 .Ar sendmail .
|
|
meillo@159
|
654 .\" XXX naechster Satz ganz raus?
|
|
meillo@85
|
655 In mmh this fixed to
|
|
meillo@85
|
656 .Ar sendmail .
|
|
meillo@85
|
657 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
|
|
meillo@85
|
658 With
|
|
meillo@100
|
659 .Sw --with-smtpservers
|
|
meillo@85
|
660 default SMTP servers for the
|
|
meillo@85
|
661 .Ar smtp
|
|
meillo@85
|
662 transport service could be specified.
|
|
meillo@72
|
663 .Ci 128545e06224233b7e91fc4c83f8830252fe16c9
|
|
meillo@85
|
664 Both of them became irrelevant.
|
|
meillo@72
|
665
|
|
meillo@74
|
666 .U3 "Backup Prefix
|
|
meillo@74
|
667 .P
|
|
meillo@76
|
668 The backup prefix is the string that was prepended to message
|
|
meillo@76
|
669 filenames to tag them as deleted.
|
|
meillo@76
|
670 By default it had been the comma character `\f(CW,\fP'.
|
|
meillo@159
|
671 .\" XXX Zeitlich ordnen
|
|
meillo@78
|
672 In July 2000, Kimmo Suominen introduced
|
|
meillo@78
|
673 the configure option
|
|
meillo@78
|
674 .Sw --with-hash-backup
|
|
meillo@78
|
675 to change the default to the hash symbol `\f(CW#\fP'.
|
|
meillo@78
|
676 The choice was probably personal preference, because first, the
|
|
meillo@78
|
677 option was named
|
|
meillo@78
|
678 .Sw --with-backup-prefix.
|
|
meillo@78
|
679 and had the prefix symbol as argument.
|
|
meillo@100
|
680 But giving the hash symbol as argument caused too many problems
|
|
meillo@100
|
681 for Autoconf,
|
|
meillo@100
|
682 thus the option was limited to use the hash symbol as the default prefix.
|
|
meillo@100
|
683 This supports the assumption, that the choice for the hash was
|
|
meillo@100
|
684 personal preference only.
|
|
meillo@100
|
685 Being related or not, words that start with the hash symbol
|
|
meillo@78
|
686 introduce a comment in the Unix shell.
|
|
meillo@72
|
687 Thus, the command line
|
|
meillo@72
|
688 .Cl "rm #13 #15
|
|
meillo@72
|
689 calls
|
|
meillo@72
|
690 .Pn rm
|
|
meillo@72
|
691 without arguments because the first hash symbol starts the comment
|
|
meillo@72
|
692 that reaches until the end of the line.
|
|
meillo@72
|
693 To delete the backup files,
|
|
meillo@72
|
694 .Cl "rm ./#13 ./#15"
|
|
meillo@72
|
695 needs to be used.
|
|
meillo@100
|
696 Using the hash as backup prefix can be seen as a precaution against
|
|
meillo@78
|
697 data loss.
|
|
meillo@78
|
698 .P
|
|
meillo@159
|
699 First, I removed the configure option but added the profile entry
|
|
meillo@72
|
700 .Pe backup-prefix ,
|
|
meillo@72
|
701 which allows to specify an arbitrary string as backup prefix.
|
|
meillo@72
|
702 .Ci 6c40d481d661d532dd527eaf34cebb6d3f8ed086
|
|
meillo@76
|
703 Profile entries are the common method to change mmh's behavior.
|
|
meillo@76
|
704 This change did not remove the choice but moved it to a location where
|
|
meillo@72
|
705 it suited better.
|
|
meillo@76
|
706 .P
|
|
meillo@78
|
707 Eventually, however, the new trash folder concept
|
|
meillo@154
|
708 (cf. Sec.
|
|
meillo@154
|
709 .Cf trash-folder )
|
|
meillo@78
|
710 obsoleted the concept of the backup prefix completely.
|
|
meillo@78
|
711 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@133
|
712 .Ci ca0b3e830b86700d9e5e31b1784de2bdcaf58fc5
|
|
meillo@133
|
713
|
|
meillo@76
|
714
|
|
meillo@76
|
715 .U3 "Editor and Pager
|
|
meillo@74
|
716 .P
|
|
meillo@74
|
717 The two configure options
|
|
meillo@74
|
718 .CW --with-editor=EDITOR
|
|
meillo@74
|
719 .CW --with-pager=PAGER
|
|
meillo@74
|
720 were used to specify the default editor and pager at configure time.
|
|
meillo@109
|
721 Doing so at configure time made sense in the eighties,
|
|
meillo@76
|
722 when the set of available editors and pagers varied much across
|
|
meillo@76
|
723 different systems.
|
|
meillo@89
|
724 Today, the situation is more homogeneous.
|
|
meillo@74
|
725 The programs
|
|
meillo@74
|
726 .Pn vi
|
|
meillo@74
|
727 and
|
|
meillo@74
|
728 .Pn more
|
|
meillo@76
|
729 can be expected to be available on every Unix system,
|
|
meillo@74
|
730 as they are specified by POSIX since two decades.
|
|
meillo@74
|
731 (The specifications for
|
|
meillo@74
|
732 .Pn vi
|
|
meillo@74
|
733 and
|
|
meillo@74
|
734 .Pn more
|
|
meillo@74
|
735 appeared in
|
|
meillo@74
|
736 .[
|
|
meillo@74
|
737 posix 1987
|
|
meillo@74
|
738 .]
|
|
meillo@74
|
739 and,
|
|
meillo@74
|
740 .[
|
|
meillo@74
|
741 posix 1992
|
|
meillo@74
|
742 .]
|
|
meillo@74
|
743 respectively.)
|
|
meillo@74
|
744 As a first step, these two tools were hard-coded as defaults.
|
|
meillo@74
|
745 .Ci 5d43a99db70c12a673028c7758c20cbe3e13ef5f
|
|
meillo@74
|
746 Not changed were the
|
|
meillo@74
|
747 .Pe editor
|
|
meillo@74
|
748 and
|
|
meillo@74
|
749 .Pe moreproc
|
|
meillo@76
|
750 profile entries, which allowed the user to override the system defaults.
|
|
meillo@74
|
751 Later, the concept was reworked to respect the standard environment
|
|
meillo@74
|
752 variables
|
|
meillo@74
|
753 .Ev VISUAL
|
|
meillo@74
|
754 and
|
|
meillo@74
|
755 .Ev PAGER
|
|
meillo@76
|
756 if they are set.
|
|
meillo@74
|
757 Today, mmh determines the editor to use in the following order,
|
|
meillo@74
|
758 taking the first available and non-empty item:
|
|
meillo@74
|
759 .IP (1)
|
|
meillo@74
|
760 Environment variable
|
|
meillo@74
|
761 .Ev MMHEDITOR
|
|
meillo@74
|
762 .IP (2)
|
|
meillo@74
|
763 Profile entry
|
|
meillo@74
|
764 .Pe Editor
|
|
meillo@74
|
765 .IP (3)
|
|
meillo@74
|
766 Environment variable
|
|
meillo@74
|
767 .Ev VISUAL
|
|
meillo@74
|
768 .IP (4)
|
|
meillo@74
|
769 Environment variable
|
|
meillo@74
|
770 .Ev EDITOR
|
|
meillo@74
|
771 .IP (5)
|
|
meillo@74
|
772 Command
|
|
meillo@74
|
773 .Pn vi .
|
|
meillo@74
|
774 .P
|
|
meillo@76
|
775 .Ci f85f4b7ae62e3d05a945dcd46ead51f0a2a89a9b
|
|
meillo@76
|
776 .P
|
|
meillo@89
|
777 The pager to use is determined in a similar order,
|
|
meillo@74
|
778 also taking the first available and non-empty item:
|
|
meillo@74
|
779 .IP (1)
|
|
meillo@74
|
780 Environment variable
|
|
meillo@74
|
781 .Ev MMHPAGER
|
|
meillo@74
|
782 .IP (2)
|
|
meillo@74
|
783 Profile entry
|
|
meillo@74
|
784 .Pe Pager
|
|
meillo@74
|
785 (replaces
|
|
meillo@74
|
786 .Pe moreproc )
|
|
meillo@74
|
787 .IP (3)
|
|
meillo@74
|
788 Environment variable
|
|
meillo@74
|
789 .Ev PAGER
|
|
meillo@74
|
790 .IP (4)
|
|
meillo@74
|
791 Command
|
|
meillo@74
|
792 .Pn more .
|
|
meillo@74
|
793 .P
|
|
meillo@74
|
794 .Ci 0c4214ea2aec6497d0d67b436bbee9bc1d225f1e
|
|
meillo@74
|
795 .P
|
|
meillo@76
|
796 By respecting the
|
|
meillo@74
|
797 .Ev VISUAL /\c
|
|
meillo@74
|
798 .Ev EDITOR
|
|
meillo@74
|
799 and
|
|
meillo@74
|
800 .Ev PAGER
|
|
meillo@76
|
801 environment variables,
|
|
meillo@76
|
802 the new behavior confirms better to the common style on Unix systems.
|
|
meillo@76
|
803 Additionally, the new approach is more uniform and clearer to users.
|
|
meillo@72
|
804
|
|
meillo@72
|
805
|
|
meillo@76
|
806 .U3 "ndbm
|
|
meillo@72
|
807 .P
|
|
meillo@74
|
808 .Pn slocal
|
|
meillo@78
|
809 used to depend on
|
|
meillo@74
|
810 .I ndbm ,
|
|
meillo@74
|
811 a database library.
|
|
meillo@76
|
812 The database is used to store the `\fLMessage-ID\fP's of all
|
|
meillo@76
|
813 messages delivered.
|
|
meillo@74
|
814 This enables
|
|
meillo@74
|
815 .Pn slocal
|
|
meillo@74
|
816 to suppress delivering the same message to the same user twice.
|
|
meillo@74
|
817 (This features was enabled by the
|
|
meillo@74
|
818 .Sw -suppressdup
|
|
meillo@74
|
819 switch.)
|
|
meillo@74
|
820 .P
|
|
meillo@100
|
821 A variety of versions of the database library exist.
|
|
meillo@78
|
822 .[
|
|
meillo@78
|
823 wolter unix incompat notes dbm
|
|
meillo@78
|
824 .]
|
|
meillo@74
|
825 Complicated autoconf code was needed to detect them correctly.
|
|
meillo@74
|
826 Further more, the configure switches
|
|
meillo@74
|
827 .Sw --with-ndbm=ARG
|
|
meillo@74
|
828 and
|
|
meillo@74
|
829 .Sw --with-ndbmheader=ARG
|
|
meillo@74
|
830 were added to help with difficult setups that would
|
|
meillo@78
|
831 not be detected automatically or correctly.
|
|
meillo@74
|
832 .P
|
|
meillo@74
|
833 By removing the suppress duplicates feature of
|
|
meillo@74
|
834 .Pn slocal ,
|
|
meillo@74
|
835 the dependency on
|
|
meillo@74
|
836 .I ndbm
|
|
meillo@78
|
837 vanished and 120 lines of complex autoconf code could be saved.
|
|
meillo@74
|
838 .Ci ecd6d6a20cb7a1507e3a20d6c4cb3a1cf14c6bbf
|
|
meillo@89
|
839 The change removed functionality too, but that is minor to the
|
|
meillo@78
|
840 improvement by dropping the dependency and the complex autoconf code.
|
|
meillo@159
|
841 .\" XXX argument: slocal ist sowieso nicht teil vom mmh kern
|
|
meillo@72
|
842
|
|
meillo@74
|
843 .U3 "mh-e Support
|
|
meillo@72
|
844 .P
|
|
meillo@74
|
845 The configure option
|
|
meillo@74
|
846 .Sw --disable-mhe
|
|
meillo@74
|
847 was removed when the mh-e support was reworked.
|
|
meillo@74
|
848 Mh-e is the Emacs front-end to MH.
|
|
meillo@76
|
849 It requires MH to provide minor additional functions.
|
|
meillo@76
|
850 The
|
|
meillo@76
|
851 .Sw --disable-mhe
|
|
meillo@76
|
852 configure option could switch these extensions off.
|
|
meillo@76
|
853 After removing the support for old versions of mh-e,
|
|
meillo@74
|
854 only the
|
|
meillo@74
|
855 .Sw -build
|
|
meillo@76
|
856 switches of
|
|
meillo@74
|
857 .Pn forw
|
|
meillo@74
|
858 and
|
|
meillo@74
|
859 .Pn repl
|
|
meillo@76
|
860 are left to be mh-e extensions.
|
|
meillo@76
|
861 They are now always built in because they add little code and complexity.
|
|
meillo@76
|
862 In consequence, the
|
|
meillo@74
|
863 .Sw --disable-mhe
|
|
meillo@76
|
864 configure option was removed
|
|
meillo@72
|
865 .Ci a7ce7b4a580d77b6c2c4d980812beb589aa4c643
|
|
meillo@74
|
866 Removing the option removed a second code setup that would have
|
|
meillo@74
|
867 needed to be tested.
|
|
meillo@159
|
868 .\" XXX datum?
|
|
meillo@76
|
869 This change was first done in nmh and thereafter merged into mmh.
|
|
meillo@76
|
870 .P
|
|
meillo@76
|
871 The interface changes in mmh require mh-e to be adjusted in order
|
|
meillo@76
|
872 to be able to use mmh as back-end.
|
|
meillo@76
|
873 This will require minor changes to mh-e, but removing the
|
|
meillo@76
|
874 .Sw -build
|
|
meillo@76
|
875 switches would require more rework.
|
|
meillo@72
|
876
|
|
meillo@74
|
877 .U3 "Masquerading
|
|
meillo@72
|
878 .P
|
|
meillo@74
|
879 The configure option
|
|
meillo@74
|
880 .Sw --enable-masquerade
|
|
meillo@76
|
881 could take up to three arguments:
|
|
meillo@76
|
882 `draft_from', `mmailid', and `username_extension'.
|
|
meillo@74
|
883 They activated different types of address masquerading.
|
|
meillo@74
|
884 All of them were implemented in the SMTP-speaking
|
|
meillo@74
|
885 .Pn post
|
|
meillo@76
|
886 command, which provided an MSA.
|
|
meillo@76
|
887 Address masquerading is an MTA's task and mmh does not cover
|
|
meillo@76
|
888 this field anymore.
|
|
meillo@76
|
889 Hence, true masquerading needs to be implemented in the external MTA.
|
|
meillo@74
|
890 .P
|
|
meillo@74
|
891 The
|
|
meillo@74
|
892 .I mmailid
|
|
meillo@74
|
893 masquerading type is the oldest one of the three and the only one
|
|
meillo@74
|
894 available in the original MH.
|
|
meillo@74
|
895 It provided a
|
|
meillo@74
|
896 .I username
|
|
meillo@74
|
897 to
|
|
meillo@74
|
898 .I fakeusername
|
|
meillo@76
|
899 mapping, based on the password file's GECOS field.
|
|
meillo@74
|
900 The man page
|
|
meillo@74
|
901 .Mp mh-tailor(5)
|
|
meillo@74
|
902 described the use case as being the following:
|
|
meillo@98
|
903 .QS
|
|
meillo@74
|
904 This is useful if you want the messages you send to always
|
|
meillo@74
|
905 appear to come from the name of an MTA alias rather than your
|
|
meillo@74
|
906 actual account name. For instance, many organizations set up
|
|
meillo@74
|
907 `First.Last' sendmail aliases for all users. If this is
|
|
meillo@74
|
908 the case, the GECOS field for each user should look like:
|
|
meillo@74
|
909 ``First [Middle] Last <First.Last>''
|
|
meillo@98
|
910 .QE
|
|
meillo@74
|
911 .P
|
|
meillo@74
|
912 As mmh sends outgoing mail via the local MTA only,
|
|
meillo@76
|
913 the best location to do such global rewrites is there.
|
|
meillo@74
|
914 Besides, the MTA is conceptionally the right location because it
|
|
meillo@74
|
915 does the reverse mapping for incoming mail (aliasing), too.
|
|
meillo@76
|
916 Further more, masquerading set up there is readily available for all
|
|
meillo@74
|
917 mail software on the system.
|
|
meillo@76
|
918 Hence, mmailid masquerading was removed.
|
|
meillo@74
|
919 .Ci 0836c8000ccb34b59410ef1c15b1b7feac70ce5f
|
|
meillo@74
|
920 .P
|
|
meillo@74
|
921 The
|
|
meillo@74
|
922 .I username_extension
|
|
meillo@76
|
923 masquerading type did not replace the username but would append a suffix,
|
|
meillo@76
|
924 specified by the
|
|
meillo@74
|
925 .Ev USERNAME_EXTENSION
|
|
meillo@76
|
926 environment variable, to it.
|
|
meillo@76
|
927 This provided support for the
|
|
meillo@74
|
928 .I user-extension
|
|
meillo@74
|
929 feature of qmail and the similar
|
|
meillo@74
|
930 .I "plussed user
|
|
meillo@74
|
931 processing of sendmail.
|
|
meillo@74
|
932 The decision to remove this username_extension masquerading was
|
|
meillo@74
|
933 motivated by the fact that
|
|
meillo@74
|
934 .Pn spost
|
|
meillo@76
|
935 hadn't supported it already.
|
|
meillo@76
|
936 .Ci 2abae0bfd0ad5bf898461e50aa4b466d641f23d9
|
|
meillo@76
|
937 Username extensions are possible in mmh, but less convenient to use.
|
|
meillo@159
|
938 .\" XXX covered by next paragraph
|
|
meillo@76
|
939 .\" XXX format file %(getenv USERNAME_EXTENSION)
|
|
meillo@74
|
940 .P
|
|
meillo@74
|
941 The
|
|
meillo@74
|
942 .I draft_from
|
|
meillo@74
|
943 masquerading type instructed
|
|
meillo@74
|
944 .Pn post
|
|
meillo@84
|
945 to use the value of the
|
|
meillo@84
|
946 .Hd From
|
|
meillo@84
|
947 header field as SMTP envelope sender.
|
|
meillo@76
|
948 Sender addresses could be replaced completely.
|
|
meillo@74
|
949 .Ci b14ea6073f77b4359aaf3fddd0e105989db9
|
|
meillo@76
|
950 Mmh offers a kind of masquerading similar in effect, but
|
|
meillo@74
|
951 with technical differences.
|
|
meillo@76
|
952 As mmh does not transfer messages itself, the local MTA has final control
|
|
meillo@76
|
953 over the sender's address. Any masquerading mmh introduces may be reverted
|
|
meillo@76
|
954 by the MTA.
|
|
meillo@76
|
955 In times of pedantic spam checking, an MTA will take care to use
|
|
meillo@76
|
956 sensible envelope sender addresses to keep its own reputation up.
|
|
meillo@84
|
957 Nonetheless, the MUA can set the
|
|
meillo@84
|
958 .Hd From
|
|
meillo@84
|
959 header field and thereby propose
|
|
meillo@76
|
960 a sender address to the MTA.
|
|
meillo@74
|
961 The MTA may then decide to take that one or generate the canonical sender
|
|
meillo@74
|
962 address for use as envelope sender address.
|
|
meillo@74
|
963 .P
|
|
meillo@74
|
964 In mmh, the MTA will always extract the recipient and sender from the
|
|
meillo@84
|
965 message header (\c
|
|
meillo@74
|
966 .Pn sendmail 's
|
|
meillo@74
|
967 .Sw -t
|
|
meillo@74
|
968 switch).
|
|
meillo@84
|
969 The
|
|
meillo@84
|
970 .Hd From
|
|
meillo@84
|
971 header field of the draft may be set arbitrary by the user.
|
|
meillo@74
|
972 If it is missing, the canonical sender address will be generated by the MTA.
|
|
meillo@74
|
973
|
|
meillo@74
|
974 .U3 "Remaining Options
|
|
meillo@74
|
975 .P
|
|
meillo@74
|
976 Two configure options remain in mmh.
|
|
meillo@74
|
977 One is the locking method to use:
|
|
meillo@74
|
978 .Sw --with-locking=[dot|fcntl|flock|lockf] .
|
|
meillo@76
|
979 The idea of removing all methods except the portable dot locking
|
|
meillo@76
|
980 and having that one as the default is appealing, but this change
|
|
meillo@76
|
981 requires deeper technical investigation into the topic.
|
|
meillo@76
|
982 The other option,
|
|
meillo@74
|
983 .Sw --enable-debug ,
|
|
meillo@74
|
984 compiles the programs with debugging symbols and does not strip them.
|
|
meillo@74
|
985 This option is likely to stay.
|
|
meillo@72
|
986
|
|
meillo@72
|
987
|
|
meillo@58
|
988
|
|
meillo@63
|
989
|
|
meillo@100
|
990 .H2 "Command Line Switches
|
|
meillo@58
|
991 .P
|
|
meillo@93
|
992 The command line switches of MH tools follow the X Window style.
|
|
meillo@93
|
993 They are words, introduced by a single dash.
|
|
meillo@93
|
994 For example:
|
|
meillo@93
|
995 .Cl "-truncate" .
|
|
meillo@93
|
996 Every program in mmh has two generic switches:
|
|
meillo@93
|
997 .Sw -help ,
|
|
meillo@93
|
998 to print a short message on how to use the program, and
|
|
meillo@159
|
999 .Sw -Version
|
|
meillo@159
|
1000 [sic!], to tell what version of mmh the program belongs to.
|
|
meillo@93
|
1001 .P
|
|
meillo@93
|
1002 Switches change the behavior of programs.
|
|
meillo@93
|
1003 Programs that do one thing in one way require no switches.
|
|
meillo@93
|
1004 In most cases, doing something in exactly one way is too limiting.
|
|
meillo@97
|
1005 If there is basically one task to accomplish, but it should be done
|
|
meillo@93
|
1006 in various ways, switches are a good approach to alter the behavior
|
|
meillo@93
|
1007 of a program.
|
|
meillo@93
|
1008 Changing the behavior of programs provides flexibility and customization
|
|
meillo@97
|
1009 to users, but at the same time it complicates the code, documentation and
|
|
meillo@93
|
1010 usage of the program.
|
|
meillo@97
|
1011 .\" XXX: Ref
|
|
meillo@93
|
1012 Therefore, the number of switches should be kept small.
|
|
meillo@93
|
1013 A small set of well-chosen switches does no harm.
|
|
meillo@93
|
1014 But usually, the number of switches increases over time.
|
|
meillo@93
|
1015 Already in 1985, Rose and Romine have identified this as a major
|
|
meillo@93
|
1016 problem of MH:
|
|
meillo@93
|
1017 .[ [
|
|
meillo@93
|
1018 rose romine real work
|
|
meillo@93
|
1019 .], p. 12]
|
|
meillo@98
|
1020 .QS
|
|
meillo@93
|
1021 A complaint often heard about systems which undergo substantial development
|
|
meillo@93
|
1022 by many people over a number of years, is that more and more options are
|
|
meillo@93
|
1023 introduced which add little to the functionality but greatly increase the
|
|
meillo@93
|
1024 amount of information a user needs to know in order to get useful work done.
|
|
meillo@93
|
1025 This is usually referred to as creeping featurism.
|
|
meillo@93
|
1026 .QP
|
|
meillo@93
|
1027 Unfortunately MH, having undergone six years of off-and-on development by
|
|
meillo@93
|
1028 ten or so well-meaning programmers (the present authors included),
|
|
meillo@93
|
1029 suffers mightily from this.
|
|
meillo@98
|
1030 .QE
|
|
meillo@93
|
1031 .P
|
|
meillo@97
|
1032 Being reluctant to adding new switches \(en or `options',
|
|
meillo@97
|
1033 as Rose and Romine call them \(en is one part of a counter-action,
|
|
meillo@97
|
1034 the other part is removing hardly used switches.
|
|
meillo@97
|
1035 Nmh's tools had lots of switches already implemented,
|
|
meillo@97
|
1036 hence, cleaning up by removing some of them was the more important part
|
|
meillo@97
|
1037 of the counter-action.
|
|
meillo@93
|
1038 Removing existing functionality is always difficult because it
|
|
meillo@93
|
1039 breaks programs that use these functions.
|
|
meillo@93
|
1040 Also, for every obsolete feature, there'll always be someone who still
|
|
meillo@93
|
1041 uses it and thus opposes its removal.
|
|
meillo@93
|
1042 This puts the developer into the position,
|
|
meillo@93
|
1043 where sensible improvements to style are regarded as destructive acts.
|
|
meillo@97
|
1044 Yet, living with the featurism is far worse, in my eyes, because
|
|
meillo@97
|
1045 future needs will demand adding further features,
|
|
meillo@93
|
1046 worsening the situation more and more.
|
|
meillo@93
|
1047 Rose and Romine added in a footnote,
|
|
meillo@93
|
1048 ``[...]
|
|
meillo@93
|
1049 .Pn send
|
|
meillo@93
|
1050 will no doubt acquire an endless number of switches in the years to come.''
|
|
meillo@97
|
1051 Although clearly humorous, the comment points to the nature of the problem.
|
|
meillo@97
|
1052 Refusing to add any new switches would encounter the problem at its root,
|
|
meillo@97
|
1053 but this is not practical.
|
|
meillo@97
|
1054 New needs will require new switches and it would be unwise to block
|
|
meillo@97
|
1055 them strictly.
|
|
meillo@97
|
1056 Nevertheless, removing obsolete switches still is an effective approach
|
|
meillo@97
|
1057 to deal with the problem.
|
|
meillo@97
|
1058 Working on an experimental branch without an established user base,
|
|
meillo@97
|
1059 eased my work because I did not offend users when I removed existing
|
|
meillo@110
|
1060 functions.
|
|
meillo@93
|
1061 .P
|
|
meillo@93
|
1062 Rose and Romine counted 24 visible and 9 more hidden switches for
|
|
meillo@93
|
1063 .Pn send .
|
|
meillo@97
|
1064 In nmh, they increased up to 32 visible and 12 hidden ones.
|
|
meillo@97
|
1065 At the time of writing, no more than 7 visible switches and 1 hidden switch
|
|
meillo@97
|
1066 have remained in mmh's
|
|
meillo@97
|
1067 .Pn send .
|
|
meillo@97
|
1068 (These numbers include two generic switches, help and version.)
|
|
meillo@93
|
1069 .P
|
|
meillo@154
|
1070 The figure displays the number of switches for each of the tools
|
|
meillo@159
|
1071 that is available in both nmh and mmh.
|
|
meillo@100
|
1072 The tools are sorted by the number of switches they had in nmh.
|
|
meillo@100
|
1073 Visible and hidden switches were counted,
|
|
meillo@97
|
1074 but not the generic help and version switches.
|
|
meillo@93
|
1075 Whereas in the beginning of the project, the average tool had 11 switches,
|
|
meillo@93
|
1076 now it has no more than 5 \(en only half as many.
|
|
meillo@93
|
1077 If the `no' switches and similar inverse variant are folded onto
|
|
meillo@100
|
1078 their counter-parts, the average tool had 8 switches in pre-mmh times and
|
|
meillo@100
|
1079 has 4 now.
|
|
meillo@93
|
1080 The total number of functional switches in mmh dropped from 465
|
|
meillo@93
|
1081 to 234.
|
|
meillo@58
|
1082
|
|
meillo@93
|
1083 .KS
|
|
meillo@93
|
1084 .in 1c
|
|
meillo@93
|
1085 .so input/switches.grap
|
|
meillo@93
|
1086 .KE
|
|
meillo@58
|
1087
|
|
meillo@93
|
1088 .P
|
|
meillo@93
|
1089 A part of the switches vanished after functions were removed.
|
|
meillo@93
|
1090 This was the case for network mail transfer, for instance.
|
|
meillo@97
|
1091 Sometimes, however, the work flow was the other way:
|
|
meillo@97
|
1092 I looked through the
|
|
meillo@97
|
1093 .Mp mh-chart (7)
|
|
meillo@97
|
1094 man page to identify the tools with apparently too many switches.
|
|
meillo@97
|
1095 Then considering the value of each of the switches by examining
|
|
meillo@97
|
1096 the tool's man page and source code, aided by recherche and testing.
|
|
meillo@97
|
1097 This way, the removal of functions was suggested by the aim to reduce
|
|
meillo@97
|
1098 the number of switches per command.
|
|
meillo@97
|
1099
|
|
meillo@58
|
1100
|
|
meillo@93
|
1101 .U3 "Draft Folder Facility
|
|
meillo@93
|
1102 .P
|
|
meillo@100
|
1103 A change early in the project was the complete transition from
|
|
meillo@93
|
1104 the single draft message to the draft folder facility.
|
|
meillo@97
|
1105 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@109
|
1106 The draft folder facility was introduced in the mid-eighties, when
|
|
meillo@100
|
1107 Rose and Romine called it a ``relatively new feature''.
|
|
meillo@93
|
1108 .[
|
|
meillo@93
|
1109 rose romine real work
|
|
meillo@93
|
1110 .]
|
|
meillo@110
|
1111 Since then, the facility had existed but was inactive by default.
|
|
meillo@93
|
1112 The default activation and the related rework of the tools made it
|
|
meillo@93
|
1113 possible to remove the
|
|
meillo@93
|
1114 .Sw -[no]draftfolder ,
|
|
meillo@93
|
1115 and
|
|
meillo@93
|
1116 .Sw -draftmessage
|
|
meillo@93
|
1117 switches from
|
|
meillo@93
|
1118 .Pn comp ,
|
|
meillo@93
|
1119 .Pn repl ,
|
|
meillo@93
|
1120 .Pn forw ,
|
|
meillo@93
|
1121 .Pn dist ,
|
|
meillo@93
|
1122 .Pn whatnow ,
|
|
meillo@93
|
1123 and
|
|
meillo@93
|
1124 .Pn send .
|
|
meillo@97
|
1125 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@97
|
1126 The only flexibility removed with this change is having multiple
|
|
meillo@97
|
1127 draft folders within one profile.
|
|
meillo@97
|
1128 I consider this a theoretical problem only.
|
|
meillo@159
|
1129 At the same time, the
|
|
meillo@93
|
1130 .Sw -draft
|
|
meillo@93
|
1131 switch of
|
|
meillo@93
|
1132 .Pn anno ,
|
|
meillo@93
|
1133 .Pn refile ,
|
|
meillo@93
|
1134 and
|
|
meillo@93
|
1135 .Pn send
|
|
meillo@93
|
1136 was removed.
|
|
meillo@159
|
1137 The special treatment of \fIthe\fP draft message became irrelevant after
|
|
meillo@93
|
1138 the rework of the draft system.
|
|
meillo@159
|
1139 (cf. Sec.
|
|
meillo@154
|
1140 .Cf draft-folder )
|
|
meillo@95
|
1141 Equally,
|
|
meillo@95
|
1142 .Pn comp
|
|
meillo@95
|
1143 lost its
|
|
meillo@95
|
1144 .Sw -file
|
|
meillo@95
|
1145 switch.
|
|
meillo@95
|
1146 The draft folder facility, together with the
|
|
meillo@95
|
1147 .Sw -form
|
|
meillo@95
|
1148 switch, are sufficient.
|
|
meillo@93
|
1149
|
|
meillo@95
|
1150
|
|
meillo@102
|
1151 .U3 "In Place Editing
|
|
meillo@93
|
1152 .P
|
|
meillo@93
|
1153 .Pn anno
|
|
meillo@93
|
1154 had the switches
|
|
meillo@93
|
1155 .Sw -[no]inplace
|
|
meillo@100
|
1156 to either annotate the message in place and thus preserve hard links,
|
|
meillo@93
|
1157 or annotate a copy to replace the original message, breaking hard links.
|
|
meillo@97
|
1158 Following the assumption that linked messages should truly be the
|
|
meillo@97
|
1159 same message, and annotating it should not break the link, the
|
|
meillo@93
|
1160 .Sw -[no]inplace
|
|
meillo@93
|
1161 switches were removed and the previous default
|
|
meillo@93
|
1162 .Sw -inplace
|
|
meillo@93
|
1163 was made the only behavior.
|
|
meillo@97
|
1164 .Ci c8195849d2e366c569271abb0f5f60f4ebf0b4d0
|
|
meillo@93
|
1165 The
|
|
meillo@93
|
1166 .Sw -[no]inplace
|
|
meillo@93
|
1167 switches of
|
|
meillo@93
|
1168 .Pn repl ,
|
|
meillo@93
|
1169 .Pn forw ,
|
|
meillo@93
|
1170 and
|
|
meillo@93
|
1171 .Pn dist
|
|
meillo@93
|
1172 could be removed, too, as they were simply passed through to
|
|
meillo@93
|
1173 .Pn anno .
|
|
meillo@93
|
1174 .P
|
|
meillo@93
|
1175 .Pn burst
|
|
meillo@93
|
1176 also had
|
|
meillo@93
|
1177 .Sw -[no]inplace
|
|
meillo@95
|
1178 switches, but with different meaning.
|
|
meillo@95
|
1179 With
|
|
meillo@95
|
1180 .Sw -inplace ,
|
|
meillo@95
|
1181 the digest had been replaced by the table of contents (i.e. the
|
|
meillo@110
|
1182 introduction text) and the burst messages were placed right
|
|
meillo@95
|
1183 after this message, renumbering all following messages.
|
|
meillo@95
|
1184 Also, any trailing text of the digest was lost, though,
|
|
meillo@95
|
1185 in practice, it usually consists of an end-of-digest marker only.
|
|
meillo@95
|
1186 Nontheless, this behavior appeared less elegant than the
|
|
meillo@95
|
1187 .Sw -noinplace
|
|
meillo@95
|
1188 behavior, which already had been the default.
|
|
meillo@95
|
1189 Nmh's
|
|
meillo@95
|
1190 .Mp burst (1)
|
|
meillo@95
|
1191 man page reads:
|
|
meillo@95
|
1192 .sp \n(PDu
|
|
meillo@98
|
1193 .QS
|
|
meillo@93
|
1194 If -noinplace is given, each digest is preserved, no table
|
|
meillo@93
|
1195 of contents is produced, and the messages contained within
|
|
meillo@93
|
1196 the digest are placed at the end of the folder. Other messages
|
|
meillo@93
|
1197 are not tampered with in any way.
|
|
meillo@98
|
1198 .QE
|
|
meillo@95
|
1199 .LP
|
|
meillo@93
|
1200 The decision to drop the
|
|
meillo@93
|
1201 .Sw -inplace
|
|
meillo@95
|
1202 behavior was supported by the code complexity and the possible data loss
|
|
meillo@95
|
1203 it caused.
|
|
meillo@93
|
1204 .Sw -noinplace
|
|
meillo@95
|
1205 was chosen to be the definitive behavior.
|
|
meillo@97
|
1206 .Ci 68a686adeb39223a5e1ad35e4a24890ec053679d
|
|
meillo@93
|
1207
|
|
meillo@95
|
1208
|
|
meillo@95
|
1209 .U3 "Forms and Format Strings
|
|
meillo@93
|
1210 .P
|
|
meillo@95
|
1211 Historically, the tools that had
|
|
meillo@95
|
1212 .Sw -form
|
|
meillo@95
|
1213 switches to supply a form file had
|
|
meillo@95
|
1214 .Sw -format
|
|
meillo@95
|
1215 switches as well to supply the contents of a form file as a string
|
|
meillo@95
|
1216 on the command line directly.
|
|
meillo@95
|
1217 In consequence, the following two lines equaled:
|
|
meillo@95
|
1218 .VS
|
|
meillo@95
|
1219 scan -form scan.mailx
|
|
meillo@95
|
1220 scan -format "`cat .../scan.mailx`"
|
|
meillo@95
|
1221 VE
|
|
meillo@95
|
1222 The
|
|
meillo@95
|
1223 .Sw -format
|
|
meillo@95
|
1224 switches were dropped in favor for extending the
|
|
meillo@95
|
1225 .Sw -form
|
|
meillo@95
|
1226 switches.
|
|
meillo@97
|
1227 .Ci f51956be123db66b00138f80464d06f030dbb88d
|
|
meillo@95
|
1228 If their argument starts with an equal sign (`='),
|
|
meillo@95
|
1229 then the rest of the argument is taken as a format string,
|
|
meillo@95
|
1230 otherwise the arguments is treated as the name of a format file.
|
|
meillo@95
|
1231 Thus, now the following two lines equal:
|
|
meillo@95
|
1232 .VS
|
|
meillo@95
|
1233 scan -form scan.mailx
|
|
meillo@95
|
1234 scan -form "=`cat .../scan.mailx`"
|
|
meillo@95
|
1235 VE
|
|
meillo@95
|
1236 This rework removed the prefix collision between
|
|
meillo@95
|
1237 .Sw -form
|
|
meillo@95
|
1238 and
|
|
meillo@95
|
1239 .Sw -format .
|
|
meillo@95
|
1240 Now, typing
|
|
meillo@95
|
1241 .Sw -fo
|
|
meillo@95
|
1242 suffices to specify form or format string.
|
|
meillo@95
|
1243 .P
|
|
meillo@95
|
1244 The different meaning of
|
|
meillo@95
|
1245 .Sw -format
|
|
meillo@95
|
1246 for
|
|
meillo@95
|
1247 .Pn repl
|
|
meillo@95
|
1248 and
|
|
meillo@95
|
1249 .Pn forw
|
|
meillo@95
|
1250 was removed in mmh.
|
|
meillo@95
|
1251 .Pn forw
|
|
meillo@95
|
1252 was completely switched to MIME-type forwarding, thus removing the
|
|
meillo@95
|
1253 .Sw -[no]format .
|
|
meillo@97
|
1254 .Ci 6e271608b7b9c23771523f88d23a4d3593010cf1
|
|
meillo@95
|
1255 For
|
|
meillo@95
|
1256 .Pn repl ,
|
|
meillo@95
|
1257 the
|
|
meillo@95
|
1258 .Sw -[no]format
|
|
meillo@95
|
1259 switches were reworked to
|
|
meillo@95
|
1260 .Sw -[no]filter
|
|
meillo@95
|
1261 switches.
|
|
meillo@97
|
1262 .Ci 67411b1f95d6ec987b4c732459e1ba8a8ac192c6
|
|
meillo@95
|
1263 The
|
|
meillo@95
|
1264 .Sw -format
|
|
meillo@95
|
1265 switches of
|
|
meillo@95
|
1266 .Pn send
|
|
meillo@95
|
1267 and
|
|
meillo@95
|
1268 .Pn post ,
|
|
meillo@95
|
1269 which had a third meaning,
|
|
meillo@95
|
1270 were removed likewise.
|
|
meillo@97
|
1271 .Ci f3cb7cde0e6f10451b6848678d95860d512224b9
|
|
meillo@95
|
1272 Eventually, the ambiguity of the
|
|
meillo@95
|
1273 .Sw -format
|
|
meillo@95
|
1274 switches was resolved by not anymore having any such switch in mmh.
|
|
meillo@95
|
1275
|
|
meillo@95
|
1276
|
|
meillo@95
|
1277 .U3 "MIME Tools
|
|
meillo@95
|
1278 .P
|
|
meillo@95
|
1279 The MIME tools, which were once part of
|
|
meillo@100
|
1280 .Pn mhn
|
|
meillo@100
|
1281 [sic!],
|
|
meillo@95
|
1282 had several switches that added little practical value to the programs.
|
|
meillo@95
|
1283 The
|
|
meillo@95
|
1284 .Sw -[no]realsize
|
|
meillo@95
|
1285 switches of
|
|
meillo@95
|
1286 .Pn mhbuild
|
|
meillo@95
|
1287 and
|
|
meillo@95
|
1288 .Pn mhlist
|
|
meillo@97
|
1289 were removed, doing real size calculations always now
|
|
meillo@97
|
1290 .Ci 8d8f1c3abc586c005c904e52c4adbfe694d2201c ,
|
|
meillo@159
|
1291 as nmh's
|
|
meillo@159
|
1292 .Mp mhbuild (1)
|
|
meillo@159
|
1293 man page states
|
|
meillo@95
|
1294 ``This provides an accurate count at the expense of a small delay.''
|
|
meillo@95
|
1295 This small delay is not noticable on modern systems.
|
|
meillo@95
|
1296 .P
|
|
meillo@95
|
1297 The
|
|
meillo@95
|
1298 .Sw -[no]check
|
|
meillo@95
|
1299 switches were removed together with the support for
|
|
meillo@95
|
1300 .Hd Content-MD5
|
|
meillo@95
|
1301 header fields.
|
|
meillo@95
|
1302 .[
|
|
meillo@95
|
1303 rfc 1864
|
|
meillo@95
|
1304 .]
|
|
meillo@97
|
1305 .Ci 31dc797eb5178970d68962ca8939da3fd9a8efda
|
|
meillo@154
|
1306 (cf. Sec.
|
|
meillo@154
|
1307 .Cf content-md5 )
|
|
meillo@95
|
1308 .P
|
|
meillo@95
|
1309 The
|
|
meillo@95
|
1310 .Sw -[no]ebcdicsafe
|
|
meillo@95
|
1311 and
|
|
meillo@95
|
1312 .Sw -[no]rfc934mode
|
|
meillo@95
|
1313 switches of
|
|
meillo@95
|
1314 .Pn mhbuild
|
|
meillo@95
|
1315 were removed because they are considered obsolete.
|
|
meillo@97
|
1316 .Ci 01a3480928da485b4d6109d36d751dfa71799d58
|
|
meillo@97
|
1317 .Ci 3363e2624dce0eb8164cf8b3f1ab385c8ff72e88
|
|
meillo@95
|
1318 .P
|
|
meillo@95
|
1319 Content caching of external MIME parts, activated with the
|
|
meillo@95
|
1320 .Sw -rcache
|
|
meillo@95
|
1321 and
|
|
meillo@95
|
1322 .Sw -wcache
|
|
meillo@95
|
1323 switches was completely removed.
|
|
meillo@97
|
1324 .Ci d1fefd9f614e4dc3cda16da6c69133c1b2005269
|
|
meillo@97
|
1325 External MIME parts are rare today, having a caching facility
|
|
meillo@159
|
1326 for them appears to be unnecessary.
|
|
meillo@95
|
1327 .P
|
|
meillo@95
|
1328 In pre-MIME times,
|
|
meillo@95
|
1329 .Pn mhl
|
|
meillo@95
|
1330 had covered many tasks that are part of MIME handling today.
|
|
meillo@95
|
1331 Therefore,
|
|
meillo@95
|
1332 .Pn mhl
|
|
meillo@95
|
1333 could be simplified to a large extend, reducing the number of its
|
|
meillo@95
|
1334 switches from 21 to 6.
|
|
meillo@97
|
1335 .Ci 350ad6d3542a07639213cf2a4fe524e829c1e7b6
|
|
meillo@97
|
1336 .Ci 0e46503be3c855bddaeae3843e1b659279c35d70
|
|
meillo@95
|
1337
|
|
meillo@95
|
1338
|
|
meillo@95
|
1339
|
|
meillo@95
|
1340
|
|
meillo@95
|
1341 .U3 "Header Printing
|
|
meillo@95
|
1342 .P
|
|
meillo@95
|
1343 .Pn folder 's
|
|
meillo@95
|
1344 data output is self-explaining enough that
|
|
meillo@159
|
1345 displaying the header line makes little sense.
|
|
meillo@95
|
1346 Hence, the
|
|
meillo@95
|
1347 .Sw -[no]header
|
|
meillo@95
|
1348 switch was removed and headers are never printed.
|
|
meillo@97
|
1349 .Ci 601cc73d1fa05ce96faa728f036d6c51b91701c7
|
|
meillo@95
|
1350 .P
|
|
meillo@95
|
1351 In
|
|
meillo@95
|
1352 .Pn mhlist ,
|
|
meillo@95
|
1353 the
|
|
meillo@95
|
1354 .Sw -[no]header
|
|
meillo@95
|
1355 switches were removed, too.
|
|
meillo@97
|
1356 .Ci b24f96523aaf60e44e04a3ffb1d22e69a13a602f
|
|
meillo@95
|
1357 But in this case headers are always printed,
|
|
meillo@95
|
1358 because the output is not self-explaining.
|
|
meillo@95
|
1359 .P
|
|
meillo@95
|
1360 .Pn scan
|
|
meillo@95
|
1361 also had
|
|
meillo@95
|
1362 .Sw -[no]header
|
|
meillo@95
|
1363 switches.
|
|
meillo@95
|
1364 Printing the header had been sensible until the introduction of
|
|
meillo@95
|
1365 format strings made it impossible to display the column headings.
|
|
meillo@95
|
1366 Only the folder name and the current date remained to be printed.
|
|
meillo@95
|
1367 As this information can be perfectly retrieved by
|
|
meillo@95
|
1368 .Pn folder
|
|
meillo@95
|
1369 and
|
|
meillo@95
|
1370 .Pn date ,
|
|
meillo@95
|
1371 consequently, the switches were removed.
|
|
meillo@97
|
1372 .Ci c477dc5d1d03fa6d9a8ab3dd3508c63cbddc044e
|
|
meillo@95
|
1373 .P
|
|
meillo@95
|
1374 By removing all
|
|
meillo@95
|
1375 .Sw -header
|
|
meillo@95
|
1376 switches, the collision with
|
|
meillo@95
|
1377 .Sw -help
|
|
meillo@95
|
1378 on the first two letters was resolved.
|
|
meillo@95
|
1379 Currently,
|
|
meillo@95
|
1380 .Sw -h
|
|
meillo@95
|
1381 evaluates to
|
|
meillo@95
|
1382 .Sw -help
|
|
meillo@95
|
1383 for all tools of mmh.
|
|
meillo@95
|
1384
|
|
meillo@95
|
1385
|
|
meillo@139
|
1386 .U3 "Suppressing Edits or the Invocation of the WhatNow Shell
|
|
meillo@95
|
1387 .P
|
|
meillo@95
|
1388 The
|
|
meillo@95
|
1389 .Sw -noedit
|
|
meillo@100
|
1390 switch of
|
|
meillo@95
|
1391 .Pn comp ,
|
|
meillo@95
|
1392 .Pn repl ,
|
|
meillo@95
|
1393 .Pn forw ,
|
|
meillo@95
|
1394 .Pn dist ,
|
|
meillo@95
|
1395 and
|
|
meillo@95
|
1396 .Pn whatnow
|
|
meillo@95
|
1397 was removed, but it can now be replaced by specifying
|
|
meillo@95
|
1398 .Sw -editor
|
|
meillo@95
|
1399 with an empty argument.
|
|
meillo@97
|
1400 .Ci 75fca31a5b9d5c1a99c74ab14c94438d8852fba9
|
|
meillo@95
|
1401 (Specifying
|
|
meillo@159
|
1402 .Cl "-editor /bin/true
|
|
meillo@95
|
1403 is nearly the same, only differing by the previous editor being set.)
|
|
meillo@95
|
1404 .P
|
|
meillo@95
|
1405 The more important change is the removal of the
|
|
meillo@95
|
1406 .Sw -nowhatnowproc
|
|
meillo@95
|
1407 switch.
|
|
meillo@97
|
1408 .Ci ee4f43cf2ef0084ec698e4e87159a94c01940622
|
|
meillo@95
|
1409 This switch had introduced an awkward behavior, as explained in nmh's
|
|
meillo@95
|
1410 man page for
|
|
meillo@95
|
1411 .Mp comp (1):
|
|
meillo@98
|
1412 .QS
|
|
meillo@98
|
1413 The \-editor editor switch indicates the editor to use for
|
|
meillo@98
|
1414 the initial edit. Upon exiting from the editor, comp will
|
|
meillo@98
|
1415 invoke the whatnow program. See whatnow(1) for a discussion
|
|
meillo@98
|
1416 of available options. The invocation of this program can be
|
|
meillo@98
|
1417 inhibited by using the \-nowhatnowproc switch. (In truth of
|
|
meillo@98
|
1418 fact, it is the whatnow program which starts the initial
|
|
meillo@98
|
1419 edit. Hence, \-nowhatnowproc will prevent any edit from
|
|
meillo@95
|
1420 occurring.)
|
|
meillo@98
|
1421 .QE
|
|
meillo@95
|
1422 .P
|
|
meillo@95
|
1423 Effectively, the
|
|
meillo@95
|
1424 .Sw -nowhatnowproc
|
|
meillo@100
|
1425 switch creates only a draft message.
|
|
meillo@95
|
1426 As
|
|
meillo@159
|
1427 .Cl "-whatnowproc /bin/true
|
|
meillo@95
|
1428 causes the same behavior, the
|
|
meillo@95
|
1429 .Sw -nowhatnowproc
|
|
meillo@95
|
1430 switch was removed for being redundant.
|
|
meillo@100
|
1431 Likely, the
|
|
meillo@95
|
1432 .Sw -nowhatnowproc
|
|
meillo@100
|
1433 switch was intended to be used by front-ends.
|
|
meillo@95
|
1434
|
|
meillo@95
|
1435
|
|
meillo@95
|
1436
|
|
meillo@95
|
1437 .U3 "Various
|
|
meillo@95
|
1438 .BU
|
|
meillo@139
|
1439 With the removal of MMDF maildrop format support,
|
|
meillo@139
|
1440 .Pn packf
|
|
meillo@139
|
1441 and
|
|
meillo@139
|
1442 .Pn rcvpack
|
|
meillo@139
|
1443 no longer needed their
|
|
meillo@139
|
1444 .Sw -mbox
|
|
meillo@139
|
1445 and
|
|
meillo@139
|
1446 .Sw -mmdf
|
|
meillo@139
|
1447 switches.
|
|
meillo@139
|
1448 .Sw -mbox
|
|
meillo@154
|
1449 is the sole behavior now.
|
|
meillo@139
|
1450 .Ci 3916ab66ad5d183705ac12357621ea8661afd3c0
|
|
meillo@139
|
1451 In the same go,
|
|
meillo@139
|
1452 .Pn packf
|
|
meillo@139
|
1453 and
|
|
meillo@139
|
1454 .Pn rcvpack
|
|
meillo@154
|
1455 were reworked and their
|
|
meillo@139
|
1456 .Sw -file
|
|
meillo@139
|
1457 switch became unnecessary.
|
|
meillo@139
|
1458 .Ci ca1023716d4c2ab890696f3e41fa0d94267a940e
|
|
meillo@139
|
1459
|
|
meillo@139
|
1460 .BU
|
|
meillo@139
|
1461 Mmh's tools will no longer clear the screen (\c
|
|
meillo@139
|
1462 .Pn scan 's
|
|
meillo@139
|
1463 and
|
|
meillo@139
|
1464 .Pn mhl 's
|
|
meillo@139
|
1465 .Sw -[no]clear
|
|
meillo@139
|
1466 switches
|
|
meillo@139
|
1467 .Ci e57b17343dcb3ff373ef4dd089fbe778f0c7c270
|
|
meillo@139
|
1468 .Ci 943765e7ac5693ae177fd8d2b5a2440e53ce816e ).
|
|
meillo@139
|
1469 Neither will
|
|
meillo@139
|
1470 .Pn mhl
|
|
meillo@139
|
1471 ring the bell (\c
|
|
meillo@139
|
1472 .Sw -[no]bell
|
|
meillo@139
|
1473 .Ci e11983f44e59d8de236affa5b0d0d3067c192e24 )
|
|
meillo@139
|
1474 nor page the output itself (\c
|
|
meillo@139
|
1475 .Sw -length
|
|
meillo@139
|
1476 .Ci 5b9d883db0318ed2b84bb82dee880d7381f99188 ).
|
|
meillo@159
|
1477 .\" XXX Ref
|
|
meillo@139
|
1478 Generally, the pager to use is no longer specified with the
|
|
meillo@139
|
1479 .Sw -[no]moreproc
|
|
meillo@139
|
1480 command line switches for
|
|
meillo@139
|
1481 .Pn mhl
|
|
meillo@139
|
1482 and
|
|
meillo@139
|
1483 .Pn show /\c
|
|
meillo@139
|
1484 .Pn mhshow .
|
|
meillo@139
|
1485 .Ci 39e87a75b5c2d3572ec72e717720b44af291e88a
|
|
meillo@139
|
1486
|
|
meillo@139
|
1487 .BU
|
|
meillo@96
|
1488 In order to avoid prefix collisions among switch names, the
|
|
meillo@95
|
1489 .Sw -version
|
|
meillo@95
|
1490 switch was renamed to
|
|
meillo@95
|
1491 .Sw -Version
|
|
meillo@95
|
1492 (with capital `V').
|
|
meillo@97
|
1493 .Ci 32b2354dbaf4bf934936eb5b102a4a3d2fdd209a
|
|
meillo@95
|
1494 Every program has the
|
|
meillo@95
|
1495 .Sw -version
|
|
meillo@95
|
1496 switch but its first three letters collided with the
|
|
meillo@95
|
1497 .Sw -verbose
|
|
meillo@95
|
1498 switch, present in many programs.
|
|
meillo@95
|
1499 The rename solved this problem once for all.
|
|
meillo@95
|
1500 Although this rename breaks a basic interface, having the
|
|
meillo@95
|
1501 .Sw -V
|
|
meillo@95
|
1502 abbreviation to display the version information, isn't all too bad.
|
|
meillo@139
|
1503
|
|
meillo@95
|
1504 .BU
|
|
meillo@95
|
1505 .Sw -[no]preserve
|
|
meillo@95
|
1506 of
|
|
meillo@95
|
1507 .Pn refile
|
|
meillo@95
|
1508 was removed because what use was it anyway?
|
|
meillo@98
|
1509 .QS
|
|
meillo@95
|
1510 Normally when a message is refiled, for each destination
|
|
meillo@95
|
1511 folder it is assigned the number which is one above the current
|
|
meillo@95
|
1512 highest message number in that folder. Use of the
|
|
meillo@95
|
1513 \-preserv [sic!] switch will override this message renaming, and try
|
|
meillo@95
|
1514 to preserve the number of the message. If a conflict for a
|
|
meillo@95
|
1515 particular folder occurs when using the \-preserve switch,
|
|
meillo@95
|
1516 then refile will use the next available message number which
|
|
meillo@95
|
1517 is above the message number you wish to preserve.
|
|
meillo@98
|
1518 .QE
|
|
meillo@139
|
1519
|
|
meillo@95
|
1520 .BU
|
|
meillo@95
|
1521 The removal of the
|
|
meillo@95
|
1522 .Sw -[no]reverse
|
|
meillo@95
|
1523 switches of
|
|
meillo@95
|
1524 .Pn scan
|
|
meillo@97
|
1525 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@95
|
1526 is a bug fix, supported by the comments
|
|
meillo@95
|
1527 ``\-[no]reverse under #ifdef BERK (I really HATE this)''
|
|
meillo@95
|
1528 by Rose and
|
|
meillo@95
|
1529 ``Lists messages in reverse order with the `\-reverse' switch.
|
|
meillo@95
|
1530 This should be considered a bug.'' by Romine in the documentation.
|
|
meillo@159
|
1531 .\" XXX Ref: welche datei genau.
|
|
meillo@97
|
1532 The question remains why neither Rose and Romine had fixed this
|
|
meillo@109
|
1533 bug in the eighties when they wrote these comments nor has anyone
|
|
meillo@95
|
1534 thereafter.
|
|
meillo@93
|
1535
|
|
meillo@93
|
1536
|
|
meillo@93
|
1537 .ig
|
|
meillo@93
|
1538
|
|
meillo@95
|
1539 forw: [no]dashstuffing(mhl)
|
|
meillo@93
|
1540
|
|
meillo@95
|
1541 mhshow: [no]pause [no]serialonly
|
|
meillo@93
|
1542
|
|
meillo@93
|
1543 mhmail: resent queued
|
|
meillo@93
|
1544 inc: snoop, (pop)
|
|
meillo@93
|
1545
|
|
meillo@95
|
1546 mhl: [no]faceproc folder sleep
|
|
meillo@95
|
1547 [no]dashstuffing(forw) digest list volume number issue number
|
|
meillo@93
|
1548
|
|
meillo@95
|
1549 prompter: [no]doteof
|
|
meillo@93
|
1550
|
|
meillo@93
|
1551 refile: [no]preserve [no]unlink [no]rmmproc
|
|
meillo@93
|
1552
|
|
meillo@95
|
1553 send: [no]forward [no]mime [no]msgid
|
|
meillo@93
|
1554 [no]push split [no]unique (sasl) width snoop [no]dashstuffing
|
|
meillo@93
|
1555 attach attachformat
|
|
meillo@93
|
1556 whatnow: (noedit) attach
|
|
meillo@93
|
1557
|
|
meillo@93
|
1558 slocal: [no]suppressdups
|
|
meillo@93
|
1559
|
|
meillo@95
|
1560 spost: [no]filter [no]backup width [no]push idanno
|
|
meillo@93
|
1561 [no]check(whom) whom(whom)
|
|
meillo@93
|
1562
|
|
meillo@93
|
1563 whom: ???
|
|
meillo@93
|
1564
|
|
meillo@95
|
1565 ..
|
|
meillo@93
|
1566
|
|
meillo@93
|
1567
|
|
meillo@93
|
1568 .ig
|
|
meillo@93
|
1569
|
|
meillo@93
|
1570 .P
|
|
meillo@93
|
1571 In the best case, all switches are unambiguous on the first character,
|
|
meillo@93
|
1572 or on the three-letter prefix for the `no' variants.
|
|
meillo@96
|
1573 Reducing switch prefix collisions, shortens the necessary prefix length
|
|
meillo@93
|
1574 the user must type.
|
|
meillo@93
|
1575 Having less switches helps best.
|
|
meillo@93
|
1576
|
|
meillo@93
|
1577 ..
|
|
meillo@58
|
1578
|
|
meillo@95
|
1579
|
|
meillo@102
|
1580 .\" XXX: whatnow prompt commands
|
|
meillo@102
|
1581
|
|
meillo@102
|
1582
|
|
meillo@95
|
1583
|
|
meillo@95
|
1584
|
|
meillo@133
|
1585 .\" --------------------------------------------------------------
|
|
meillo@74
|
1586 .H1 "Modernizing
|
|
meillo@102
|
1587 .P
|
|
meillo@159
|
1588 In the more thirty years of MH's existence, its code base was
|
|
meillo@159
|
1589 increasingly extended.
|
|
meillo@118
|
1590 New features entered the project and became alternatives to the
|
|
meillo@118
|
1591 existing behavior.
|
|
meillo@118
|
1592 Relicts from several decades have gathered in the code base,
|
|
meillo@118
|
1593 but seldom obsolete features were dropped.
|
|
meillo@118
|
1594 This section describes the removing of old code
|
|
meillo@118
|
1595 and the modernizing of the default setup.
|
|
meillo@118
|
1596 It focuses on the functional aspect only;
|
|
meillo@154
|
1597 the non-functional aspects of code style are discussed in Sec.
|
|
meillo@154
|
1598 .Cf code-style .
|
|
meillo@58
|
1599
|
|
meillo@58
|
1600
|
|
meillo@100
|
1601 .H2 "Code Relicts
|
|
meillo@0
|
1602 .P
|
|
meillo@159
|
1603 My position regarding the removal of obsolete functions of mmh,
|
|
meillo@159
|
1604 .\" XXX ``in order to remove old code,''
|
|
meillo@159
|
1605 is much more revolutional than the nmh community appreciates.
|
|
meillo@159
|
1606 Working on an experimental version, I was quickly able to drop
|
|
meillo@104
|
1607 functionality I considered ancient.
|
|
meillo@104
|
1608 The need for consensus with peers would have slowed this process down.
|
|
meillo@104
|
1609 Without the need to justify my decisions, I was able to rush forward.
|
|
meillo@110
|
1610 In December 2011, Paul Vixie motivated the nmh developers to just
|
|
meillo@159
|
1611 .\" XXX ugs
|
|
meillo@104
|
1612 do the work:
|
|
meillo@104
|
1613 .[
|
|
meillo@104
|
1614 paul vixie edginess nmh-workers
|
|
meillo@104
|
1615 .]
|
|
meillo@104
|
1616 .QS
|
|
meillo@104
|
1617 let's stop walking on egg shells with this code base. there's no need to
|
|
meillo@104
|
1618 discuss whether to keep using vfork, just note in [sic!] passing, [...]
|
|
meillo@104
|
1619 we don't need a separate branch for removing vmh
|
|
meillo@104
|
1620 or ridding ourselves of #ifdef's or removing posix replacement functions
|
|
meillo@104
|
1621 or depending on pure ansi/posix "libc".
|
|
meillo@104
|
1622 .QP
|
|
meillo@104
|
1623 these things should each be a day or two of work and the "main branch"
|
|
meillo@104
|
1624 should just be modern. [...]
|
|
meillo@104
|
1625 let's push forward, aggressively.
|
|
meillo@104
|
1626 .QE
|
|
meillo@104
|
1627 .LP
|
|
meillo@104
|
1628 I did so already in the months before.
|
|
meillo@104
|
1629 I pushed forward.
|
|
meillo@159
|
1630 .\" XXX semicolon ?
|
|
meillo@104
|
1631 I simply dropped the cruft.
|
|
meillo@104
|
1632 .P
|
|
meillo@104
|
1633 The decision to drop a feature was based on literature research and
|
|
meillo@159
|
1634 careful thinking, but whether having had contact with this particular
|
|
meillo@104
|
1635 feature within my own computer life served as a rule of thumb.
|
|
meillo@159
|
1636 I explained my reasons in the commit messages
|
|
meillo@109
|
1637 in the version control system.
|
|
meillo@104
|
1638 Hence, others can comprehend my view and argue for undoing the change
|
|
meillo@104
|
1639 if I have missed an important aspect.
|
|
meillo@109
|
1640 I was quick in dropping parts.
|
|
meillo@159
|
1641 I rather re-included falsely dropped parts than going at a slower pace.
|
|
meillo@109
|
1642 Mmh is experimental work; it required tough decisions.
|
|
meillo@159
|
1643 .\" XXX ``exp. work'' schon oft gesagt
|
|
meillo@12
|
1644
|
|
meillo@102
|
1645
|
|
meillo@104
|
1646 .U3 "Forking
|
|
meillo@12
|
1647 .P
|
|
meillo@109
|
1648 Being a tool chest, MH creates many processes.
|
|
meillo@104
|
1649 In earlier times
|
|
meillo@104
|
1650 .Fu fork()
|
|
meillo@104
|
1651 had been an expensive system call, because the process's image needed
|
|
meillo@159
|
1652 to be completely duplicated at once.
|
|
meillo@159
|
1653 This expensive work was especially unnecessary in the commonly occuring
|
|
meillo@159
|
1654 case wherein the image is replaced by a call to
|
|
meillo@104
|
1655 .Fu exec()
|
|
meillo@104
|
1656 right after having forked the child process.
|
|
meillo@104
|
1657 The
|
|
meillo@104
|
1658 .Fu vfork()
|
|
meillo@104
|
1659 system call was invented to speed up this particular case.
|
|
meillo@104
|
1660 It completely omits the duplication of the image.
|
|
meillo@104
|
1661 On old systems this resulted in significant speed ups.
|
|
meillo@104
|
1662 Therefore MH used
|
|
meillo@104
|
1663 .Fu vfork()
|
|
meillo@104
|
1664 whenever possible.
|
|
meillo@12
|
1665 .P
|
|
meillo@104
|
1666 Modern memory management units support copy-on-write semantics, which make
|
|
meillo@104
|
1667 .Fu fork()
|
|
meillo@104
|
1668 almost as fast as
|
|
meillo@104
|
1669 .Fu vfork() .
|
|
meillo@104
|
1670 The man page of
|
|
meillo@104
|
1671 .Mp vfork (2)
|
|
meillo@104
|
1672 in FreeBSD 8.0 states:
|
|
meillo@104
|
1673 .QS
|
|
meillo@104
|
1674 This system call will be eliminated when proper system sharing mechanisms
|
|
meillo@104
|
1675 are implemented. Users should not depend on the memory sharing semantics
|
|
meillo@104
|
1676 of vfork() as it will, in that case, be made synonymous to fork(2).
|
|
meillo@104
|
1677 .QE
|
|
meillo@104
|
1678 .LP
|
|
meillo@104
|
1679 Vixie supports the removal with the note that ``the last
|
|
meillo@104
|
1680 system on which fork was so slow that an mh user would notice it, was
|
|
meillo@104
|
1681 Eunice. that was 1987''.
|
|
meillo@104
|
1682 .[
|
|
meillo@104
|
1683 nmh-workers vixie edginess
|
|
meillo@104
|
1684 .]
|
|
meillo@104
|
1685 I replaced all calls to
|
|
meillo@104
|
1686 .Fu vfork()
|
|
meillo@104
|
1687 with calls to
|
|
meillo@104
|
1688 .Fu fork() .
|
|
meillo@109
|
1689 .Ci 40821f5c1316e9205a08375e7075909cc9968e7d
|
|
meillo@104
|
1690 .P
|
|
meillo@104
|
1691 Related to the costs of
|
|
meillo@104
|
1692 .Fu fork()
|
|
meillo@104
|
1693 is the probability of its success.
|
|
meillo@109
|
1694 In the eighties, on heavy loaded systems, calls to
|
|
meillo@104
|
1695 .Fu fork()
|
|
meillo@104
|
1696 were prone to failure.
|
|
meillo@104
|
1697 Hence, many of the
|
|
meillo@104
|
1698 .Fu fork()
|
|
meillo@104
|
1699 calls in the code were wrapped into loops to retry the
|
|
meillo@104
|
1700 .Fu fork()
|
|
meillo@159
|
1701 several times, to increase the chances to succeed, eventually.
|
|
meillo@109
|
1702 On modern systems, a failing
|
|
meillo@104
|
1703 .Fu fork()
|
|
meillo@109
|
1704 call is unusual.
|
|
meillo@104
|
1705 Hence, in the rare case when
|
|
meillo@104
|
1706 .Fu fork()
|
|
meillo@104
|
1707 fails, mmh programs simply abort.
|
|
meillo@109
|
1708 .Ci 5fbf37ee68e018998ada61eeab73e035b26834b6
|
|
meillo@12
|
1709
|
|
meillo@12
|
1710
|
|
meillo@109
|
1711 .U3 "Header Fields
|
|
meillo@104
|
1712 .BU
|
|
meillo@84
|
1713 The
|
|
meillo@84
|
1714 .Hd Encrypted
|
|
meillo@104
|
1715 header field was introduced by RFC\|822,
|
|
meillo@109
|
1716 but already marked as legacy in RFC\|2822.
|
|
meillo@109
|
1717 Today, OpenPGP provides the basis for standardized exchange of encrypted
|
|
meillo@104
|
1718 messages [RFC\|4880, RFC\|3156].
|
|
meillo@109
|
1719 Hence, the support for
|
|
meillo@104
|
1720 .Hd Encrypted
|
|
meillo@104
|
1721 header fields is removed in mmh.
|
|
meillo@109
|
1722 .Ci 064527f7b57ab050e5af13e15ad99aeeab125857
|
|
meillo@104
|
1723 .BU
|
|
meillo@159
|
1724 The native support for
|
|
meillo@84
|
1725 .Hd Face
|
|
meillo@104
|
1726 header fields has been removed, as well.
|
|
meillo@109
|
1727 .Ci 8e5be81f784682822f5e868c1bf3c8624682bd23
|
|
meillo@104
|
1728 This feature is similar to the
|
|
meillo@84
|
1729 .Hd X-Face
|
|
meillo@84
|
1730 header field in its intent,
|
|
meillo@21
|
1731 but takes a different approach to store the image.
|
|
meillo@84
|
1732 Instead of encoding the image data directly into the header field,
|
|
meillo@109
|
1733 it contains the hostname and UDP port where the image
|
|
meillo@109
|
1734 date can be retrieved.
|
|
meillo@159
|
1735 There is even a third Face system,
|
|
meillo@109
|
1736 which is the successor of
|
|
meillo@109
|
1737 .Hd X-Face ,
|
|
meillo@109
|
1738 although it re-uses the
|
|
meillo@104
|
1739 .Hd Face
|
|
meillo@109
|
1740 header field.
|
|
meillo@109
|
1741 It was invented in 2005 and supports colored PNG images.
|
|
meillo@104
|
1742 None of the Face systems described here is popular today.
|
|
meillo@104
|
1743 Hence, mmh has no direct support for them.
|
|
meillo@104
|
1744 .BU
|
|
meillo@154
|
1745 .Id content-md5
|
|
meillo@104
|
1746 The
|
|
meillo@104
|
1747 .Hd Content-MD5
|
|
meillo@104
|
1748 header field was introduced by RFC\|1864.
|
|
meillo@104
|
1749 It provides detection of data corruption during the transfer.
|
|
meillo@104
|
1750 But it can not ensure verbatim end-to-end delivery of the contents
|
|
meillo@104
|
1751 [RFC\|1864].
|
|
meillo@104
|
1752 The proper approach to verify content integrity in an
|
|
meillo@104
|
1753 end-to-end relationship is the use of digital cryptography.
|
|
meillo@104
|
1754 .\" XXX (RFCs FIXME).
|
|
meillo@104
|
1755 On the other hand, transfer protocols should detect corruption during
|
|
meillo@109
|
1756 the transmission.
|
|
meillo@109
|
1757 The TCP includes a checksum field therefore.
|
|
meillo@104
|
1758 These two approaches in combinations render the
|
|
meillo@104
|
1759 .Hd Content-MD5
|
|
meillo@104
|
1760 header field superfluous.
|
|
meillo@109
|
1761 Not a single one out of 4\|200 messages from two decades
|
|
meillo@109
|
1762 in an nmh-workers mailing list archive contains a
|
|
meillo@104
|
1763 .Hd Content-MD5
|
|
meillo@104
|
1764 header field.
|
|
meillo@104
|
1765 Neither did any of the 60\|000 messages in my personal mail storage.
|
|
meillo@104
|
1766 Removing the support for this header field,
|
|
meillo@104
|
1767 removed the last place where MD5 computation was needed.
|
|
meillo@109
|
1768 .Ci 31dc797eb5178970d68962ca8939da3fd9a8efda
|
|
meillo@104
|
1769 Hence, the MD5 code could be removed as well.
|
|
meillo@104
|
1770 Over 500 lines of code vanished by this one change.
|
|
meillo@104
|
1771
|
|
meillo@104
|
1772
|
|
meillo@104
|
1773 .U3 "MMDF maildrop support
|
|
meillo@21
|
1774 .P
|
|
meillo@104
|
1775 This type of format is conceptionally similar to the mbox format,
|
|
meillo@139
|
1776 but uses a different message delimiter (`\fL\\1\\1\\1\\1\fP',
|
|
meillo@139
|
1777 commonly written as `\fL^A^A^A^A\fP', instead of `\fLFrom\0\fP').
|
|
meillo@104
|
1778 Mbox is the de-facto standard maildrop format on Unix,
|
|
meillo@159
|
1779 whereas the MMDF maildrop format is now forgotten.
|
|
meillo@159
|
1780 By dropping the MMDF maildrop format support,
|
|
meillo@159
|
1781 mbox became the only packed mailbox format supported in mmh.
|
|
meillo@104
|
1782 .P
|
|
meillo@109
|
1783 The simplifications within the code were moderate.
|
|
meillo@109
|
1784 Mainly, the reading and writing of MMDF mailbox files was removed.
|
|
meillo@109
|
1785 But also, switches of
|
|
meillo@109
|
1786 .Pn packf
|
|
meillo@104
|
1787 and
|
|
meillo@109
|
1788 .Pn rcvpack
|
|
meillo@109
|
1789 could be removed.
|
|
meillo@109
|
1790 .Ci 3916ab66ad5d183705ac12357621ea8661afd3c0
|
|
meillo@109
|
1791 In the message parsing function
|
|
meillo@109
|
1792 .Fn sbr/m_getfld.c ,
|
|
meillo@109
|
1793 knowledge of MMDF packed mail boxes was removed.
|
|
meillo@109
|
1794 .Ci 684ec30d81e1223a282764452f4902ed4ad1c754
|
|
meillo@109
|
1795 Further code structure simplifications may be possible there,
|
|
meillo@109
|
1796 because only one single packed mailbox format is left to be supported.
|
|
meillo@104
|
1797 I have not worked on them yet because
|
|
meillo@104
|
1798 .Fu m_getfld()
|
|
meillo@104
|
1799 is heavily optimized and thus dangerous to touch.
|
|
meillo@104
|
1800 The risk of damaging the intricate workings of the optimized code is
|
|
meillo@104
|
1801 too high.
|
|
meillo@104
|
1802
|
|
meillo@12
|
1803
|
|
meillo@101
|
1804 .U3 "Prompter's Control Keys
|
|
meillo@20
|
1805 .P
|
|
meillo@20
|
1806 The program
|
|
meillo@20
|
1807 .Pn prompter
|
|
meillo@104
|
1808 queries the user to fill in a message form.
|
|
meillo@104
|
1809 When used by
|
|
meillo@20
|
1810 .Pn comp
|
|
meillo@104
|
1811 as
|
|
meillo@104
|
1812 .Cl "comp -editor prompter" ,
|
|
meillo@20
|
1813 the resulting behavior is similar to
|
|
meillo@20
|
1814 .Pn mailx .
|
|
meillo@51
|
1815 Apparently,
|
|
meillo@20
|
1816 .Pn prompter
|
|
meillo@104
|
1817 hadn't been touched lately.
|
|
meillo@104
|
1818 Otherwise it's hardly explainable why it
|
|
meillo@20
|
1819 still offered the switches
|
|
meillo@84
|
1820 .Sw -erase
|
|
meillo@84
|
1821 .Ar chr
|
|
meillo@20
|
1822 and
|
|
meillo@84
|
1823 .Sw -kill
|
|
meillo@84
|
1824 .Ar chr
|
|
meillo@20
|
1825 to name the characters for command line editing.
|
|
meillo@21
|
1826 The times when this had been necessary are long time gone.
|
|
meillo@20
|
1827 Today these things work out-of-the-box, and if not, are configured
|
|
meillo@20
|
1828 with the standard tool
|
|
meillo@20
|
1829 .Pn stty .
|
|
meillo@104
|
1830 The switches are removed now
|
|
meillo@104
|
1831 .Ci 0bd9750710cdbab80cfb4036dd87af20afe1552f .
|
|
meillo@20
|
1832
|
|
meillo@104
|
1833
|
|
meillo@109
|
1834 .U3 "Hardcopy Terminal Support
|
|
meillo@21
|
1835 .P
|
|
meillo@109
|
1836 More of a funny anecdote is a check for being connected to a
|
|
meillo@109
|
1837 hardcopy terminal.
|
|
meillo@159
|
1838 It remained in the code until spring 2012, when I finally removed it
|
|
meillo@104
|
1839 .Ci b7764c4a6b71d37918a97594d866258f154017ca .
|
|
meillo@21
|
1840 .P
|
|
meillo@109
|
1841 The check only prevented a pager to be placed between the printing
|
|
meillo@104
|
1842 program (\c
|
|
meillo@104
|
1843 .Pn mhl )
|
|
meillo@104
|
1844 and the terminal.
|
|
meillo@109
|
1845 In nmh, this could have been ensured statically with the
|
|
meillo@104
|
1846 .Sw -nomoreproc
|
|
meillo@109
|
1847 at the command line, too.
|
|
meillo@121
|
1848 In mmh, setting the profile entry
|
|
meillo@104
|
1849 .Pe Pager
|
|
meillo@104
|
1850 or the environment variable
|
|
meillo@104
|
1851 .Ev PAGER
|
|
meillo@104
|
1852 to
|
|
meillo@109
|
1853 .Pn cat
|
|
meillo@159
|
1854 is sufficient.
|
|
meillo@104
|
1855
|
|
meillo@104
|
1856
|
|
meillo@21
|
1857
|
|
meillo@12
|
1858
|
|
meillo@58
|
1859 .H2 "Attachments
|
|
meillo@22
|
1860 .P
|
|
meillo@101
|
1861 The mind model of email attachments is unrelated to MIME.
|
|
meillo@101
|
1862 Although the MIME RFCs (2045 through 2049) define the technical
|
|
meillo@109
|
1863 requirements for having attachments, they do not mention the word
|
|
meillo@101
|
1864 ``attachment''.
|
|
meillo@101
|
1865 Instead of attachments, MIME talks about ``multi-part message bodies''
|
|
meillo@101
|
1866 [RFC\|2045], a more general concept.
|
|
meillo@101
|
1867 Multi-part messages are messages
|
|
meillo@101
|
1868 ``in which one or more different
|
|
meillo@101
|
1869 sets of data are combined in a single body''
|
|
meillo@101
|
1870 [RFC\|2046].
|
|
meillo@101
|
1871 MIME keeps its descriptions generic;
|
|
meillo@101
|
1872 it does not imply specific usage models.
|
|
meillo@109
|
1873 One usage model became prevalent: attachments.
|
|
meillo@101
|
1874 The idea is having a main text document with files of arbitrary kind
|
|
meillo@101
|
1875 attached to it.
|
|
meillo@101
|
1876 In MIME terms, this is a multi-part message having a text part first
|
|
meillo@110
|
1877 and parts of arbitrary type following.
|
|
meillo@101
|
1878 .P
|
|
meillo@101
|
1879 MH's MIME support is a direct implementation of the RFCs.
|
|
meillo@101
|
1880 The perception of the topic described in the RFCs is clearly visible
|
|
meillo@101
|
1881 in MH's implementation.
|
|
meillo@159
|
1882 .\" XXX rewrite ``no idea''.
|
|
meillo@159
|
1883 As a result,
|
|
meillo@159
|
1884 MH had all the MIME features but no idea of attachments.
|
|
meillo@109
|
1885 But users don't need all the MIME features,
|
|
meillo@109
|
1886 they want convenient attachment handling.
|
|
meillo@109
|
1887
|
|
meillo@102
|
1888
|
|
meillo@102
|
1889 .U3 "Composing MIME Messages
|
|
meillo@102
|
1890 .P
|
|
meillo@102
|
1891 In order to improve the situation on the message composing side,
|
|
meillo@102
|
1892 Jon Steinhart had added an attachment system to nmh in 2002.
|
|
meillo@101
|
1893 .Ci 7480dbc14bc90f2d872d434205c0784704213252
|
|
meillo@102
|
1894 In the file
|
|
meillo@102
|
1895 .Fn docs/README-ATTACHMENTS ,
|
|
meillo@102
|
1896 he described his motivation to do so as such:
|
|
meillo@101
|
1897 .QS
|
|
meillo@159
|
1898 Although nmh contains the necessary functionality for MIME message
|
|
meillo@159
|
1899 handing [sic!], the interface to this functionality is pretty obtuse.
|
|
meillo@101
|
1900 There's no way that I'm ever going to convince my partner to write
|
|
meillo@101
|
1901 .Pn mhbuild
|
|
meillo@101
|
1902 composition files!
|
|
meillo@101
|
1903 .QE
|
|
meillo@102
|
1904 .LP
|
|
meillo@102
|
1905 With this change, the mind model of attachments entered nmh.
|
|
meillo@102
|
1906 In the same document:
|
|
meillo@101
|
1907 .QS
|
|
meillo@101
|
1908 These changes simplify the task of managing attachments on draft files.
|
|
meillo@101
|
1909 They allow attachments to be added, listed, and deleted.
|
|
meillo@101
|
1910 MIME messages are automatically created when drafts with attachments
|
|
meillo@101
|
1911 are sent.
|
|
meillo@101
|
1912 .QE
|
|
meillo@102
|
1913 .LP
|
|
meillo@102
|
1914 Unfortunately, the attachment system,
|
|
meillo@102
|
1915 like any new facilities in nmh,
|
|
meillo@110
|
1916 was inactive by default.
|
|
meillo@101
|
1917 .P
|
|
meillo@101
|
1918 During my work in Argentina, I tried to improve the attachment system.
|
|
meillo@102
|
1919 But, because of great opposition in the nmh community,
|
|
meillo@102
|
1920 my patch died as a proposal on the mailing list, after long discussions.
|
|
meillo@101
|
1921 .[
|
|
meillo@101
|
1922 nmh-workers attachment proposal
|
|
meillo@101
|
1923 .]
|
|
meillo@110
|
1924 In January 2012, I extended the patch and applied it to mmh.
|
|
meillo@101
|
1925 .Ci 8ff284ff9167eff8f5349481529332d59ed913b1
|
|
meillo@102
|
1926 In mmh, the attachment system is active by default.
|
|
meillo@102
|
1927 Instead of command line switches, the
|
|
meillo@102
|
1928 .Pe Attachment-Header
|
|
meillo@102
|
1929 profile entry is used to specify
|
|
meillo@102
|
1930 the name of the attachment header field.
|
|
meillo@102
|
1931 It is pre-defined to
|
|
meillo@102
|
1932 .Hd Attach .
|
|
meillo@101
|
1933 .P
|
|
meillo@159
|
1934 To add an attachment to a draft, a header line needs to be added:
|
|
meillo@101
|
1935 .VS
|
|
meillo@101
|
1936 To: bob
|
|
meillo@101
|
1937 Subject: The file you wanted
|
|
meillo@101
|
1938 Attach: /path/to/the/file-bob-wanted
|
|
meillo@101
|
1939 --------
|
|
meillo@101
|
1940 Here it is.
|
|
meillo@101
|
1941 VE
|
|
meillo@101
|
1942 The header field can be added to the draft manually in the editor,
|
|
meillo@102
|
1943 or by using the `attach' command at the WhatNow prompt, or
|
|
meillo@102
|
1944 non-interactively with
|
|
meillo@101
|
1945 .Pn anno :
|
|
meillo@101
|
1946 .VS
|
|
meillo@102
|
1947 anno -append -nodate -component Attach -text /path/to/attachment
|
|
meillo@101
|
1948 VE
|
|
meillo@102
|
1949 Drafts with attachment headers are converted to MIME automatically by
|
|
meillo@102
|
1950 .Pn send .
|
|
meillo@102
|
1951 The conversion to MIME is invisible to the user.
|
|
meillo@159
|
1952 The draft stored in the draft folder is always in source form with
|
|
meillo@101
|
1953 attachment headers.
|
|
meillo@101
|
1954 If the MIMEification fails, for instance because the file to attach
|
|
meillo@101
|
1955 is not accessible, the original draft is not changed.
|
|
meillo@101
|
1956 .P
|
|
meillo@102
|
1957 The attachment system handles the forwarding of messages, too.
|
|
meillo@101
|
1958 If the attachment header value starts with a plus character (`+'),
|
|
meillo@101
|
1959 like in
|
|
meillo@101
|
1960 .Cl "Attach: +bob 30 42" ,
|
|
meillo@159
|
1961 the given messages in the specified folder will be attached.
|
|
meillo@101
|
1962 This allowed to simplify
|
|
meillo@101
|
1963 .Pn forw .
|
|
meillo@101
|
1964 .Ci f41f04cf4ceca7355232cf7413e59afafccc9550
|
|
meillo@101
|
1965 .P
|
|
meillo@101
|
1966 Closely related to attachments is non-ASCII text content,
|
|
meillo@101
|
1967 because it requires MIME too.
|
|
meillo@102
|
1968 In nmh, the user needed to call `mime' at the WhatNow prompt
|
|
meillo@101
|
1969 to have the draft converted to MIME.
|
|
meillo@102
|
1970 This was necessary whenever the draft contained non-ASCII characters.
|
|
meillo@101
|
1971 If the user did not call `mime', a broken message would be sent.
|
|
meillo@101
|
1972 Therefore, the
|
|
meillo@101
|
1973 .Pe automimeproc
|
|
meillo@101
|
1974 profile entry could be specified to have the `mime' command invoked
|
|
meillo@102
|
1975 automatically each time.
|
|
meillo@159
|
1976 Unfortunately, this approach conflicted with attachment system
|
|
meillo@101
|
1977 because the draft would already be in MIME format at the time
|
|
meillo@101
|
1978 when the attachment system wanted to MIMEify it.
|
|
meillo@102
|
1979 To use nmh's attachment system, `mime' must not be called at the
|
|
meillo@102
|
1980 WhatNow prompt and
|
|
meillo@101
|
1981 .Pe automimeproc
|
|
meillo@102
|
1982 must not be set in the profile.
|
|
meillo@101
|
1983 But then the case of non-ASCII text without attachment headers was
|
|
meillo@101
|
1984 not caught.
|
|
meillo@102
|
1985 All in all, the solution was complex and irritating.
|
|
meillo@102
|
1986 My patch from December 2010 would have simplified the situation.
|
|
meillo@102
|
1987 .P
|
|
meillo@101
|
1988 Mmh's current solution is even more elaborate.
|
|
meillo@101
|
1989 Any necessary MIMEification is done automatically.
|
|
meillo@101
|
1990 There is no `mime' command at the WhatNow prompt anymore.
|
|
meillo@102
|
1991 The draft will be converted automatically to MIME when either an
|
|
meillo@102
|
1992 attachment header or non-ASCII text is present.
|
|
meillo@159
|
1993 Furthermore, the hash character (`#') is not special any more
|
|
meillo@159
|
1994 at line beginnings in the draft message.
|
|
meillo@159
|
1995 .\" XXX REF ?
|
|
meillo@159
|
1996 Users need not concern themselves with the whole topic at all.
|
|
meillo@101
|
1997 .P
|
|
meillo@102
|
1998 Although the new approach does not anymore support arbitrary MIME
|
|
meillo@102
|
1999 compositions directly, the full power of
|
|
meillo@101
|
2000 .Pn mhbuild
|
|
meillo@101
|
2001 can still be accessed.
|
|
meillo@102
|
2002 Given no attachment headers are included, the user can create
|
|
meillo@101
|
2003 .Pn mhbuild
|
|
meillo@102
|
2004 composition drafts like in nmh.
|
|
meillo@101
|
2005 Then, at the WhatNow prompt, he needs to invoke
|
|
meillo@101
|
2006 .Cl "edit mhbuild
|
|
meillo@101
|
2007 to convert it to MIME.
|
|
meillo@110
|
2008 Because the resulting draft does neither contain non-ASCII characters
|
|
meillo@102
|
2009 nor has it attachment headers, the attachment system will not touch it.
|
|
meillo@101
|
2010 .P
|
|
meillo@159
|
2011 The approach taken in mmh is tailored towards today's most common case:
|
|
meillo@159
|
2012 a text part, possibly with attachments.
|
|
meillo@159
|
2013 This case was simplified.
|
|
meillo@102
|
2014
|
|
meillo@112
|
2015
|
|
meillo@102
|
2016 .U3 "MIME Type Guessing
|
|
meillo@102
|
2017 .P
|
|
meillo@159
|
2018 From the programmer's point of view, the use of
|
|
meillo@101
|
2019 .Pn mhbuild
|
|
meillo@159
|
2020 composition drafts had one notable advantage over attachment headers:
|
|
meillo@159
|
2021 The user provides the appropriate MIME types for files to include.
|
|
meillo@102
|
2022 The attachment system needs to find out the correct MIME type itself.
|
|
meillo@102
|
2023 This is a difficult task, yet it spares the user irritating work.
|
|
meillo@102
|
2024 Determining the correct MIME type of content is partly mechanical,
|
|
meillo@102
|
2025 partly intelligent work.
|
|
meillo@102
|
2026 Forcing the user to find out the correct MIME type,
|
|
meillo@102
|
2027 forces him to do partly mechanical work.
|
|
meillo@102
|
2028 Letting the computer do the work, can lead to bad choices for difficult
|
|
meillo@102
|
2029 content.
|
|
meillo@102
|
2030 For mmh, the latter option was chosen.
|
|
meillo@102
|
2031 .P
|
|
meillo@102
|
2032 Determining the MIME type by the suffix of the file name is a dumb
|
|
meillo@102
|
2033 approach, yet it is simple to implement and provides good results
|
|
meillo@102
|
2034 for the common cases.
|
|
meillo@102
|
2035 Mmh implements this approach in the
|
|
meillo@102
|
2036 .Pn print-mimetype
|
|
meillo@102
|
2037 script.
|
|
meillo@112
|
2038 .Ci 4b5944268ea0da7bb30598a27857304758ea9b44
|
|
meillo@102
|
2039 Using it is the default choice.
|
|
meillo@102
|
2040 .P
|
|
meillo@112
|
2041 A far better, though less portable, approach is the use of
|
|
meillo@102
|
2042 .Pn file .
|
|
meillo@102
|
2043 This standard tool tries to determine the type of files.
|
|
meillo@102
|
2044 Unfortunately, its capabilities and accuracy varies from system to system.
|
|
meillo@102
|
2045 Additionally, its output was only intended for human beings,
|
|
meillo@102
|
2046 but not to be used by programs.
|
|
meillo@102
|
2047 It varies much.
|
|
meillo@102
|
2048 Nevertheless, modern versions of GNU
|
|
meillo@102
|
2049 .Pn file ,
|
|
meillo@102
|
2050 which is prevalent on the popular GNU/Linux systems,
|
|
meillo@159
|
2051 provide MIME type output in machine-readable form.
|
|
meillo@102
|
2052 Although this solution is highly system-dependent,
|
|
meillo@102
|
2053 it solves the difficult problem well.
|
|
meillo@102
|
2054 On systems where GNU
|
|
meillo@102
|
2055 .Pn file ,
|
|
meillo@102
|
2056 version 5.04 or higher, is available it should be used.
|
|
meillo@102
|
2057 One needs to specify the following profile entry to do so:
|
|
meillo@112
|
2058 .Ci 3baec236a39c5c89a9bda8dbd988d643a21decc6
|
|
meillo@102
|
2059 .VS
|
|
meillo@102
|
2060 Mime-Type-Query: file -b --mime
|
|
meillo@102
|
2061 VE
|
|
meillo@102
|
2062 .LP
|
|
meillo@102
|
2063 Other versions of
|
|
meillo@102
|
2064 .Pn file
|
|
meillo@102
|
2065 might possibly be usable with wrapper scripts to reformat the output.
|
|
meillo@102
|
2066 The diversity among
|
|
meillo@102
|
2067 .Pn file
|
|
meillo@102
|
2068 implementations is great; one needs to check the local variant.
|
|
meillo@102
|
2069 .P
|
|
meillo@102
|
2070 If no MIME type can be determined, text content gets sent as
|
|
meillo@102
|
2071 `text/plain' and anything else under the generic fall-back type
|
|
meillo@102
|
2072 `application/octet-stream'.
|
|
meillo@102
|
2073 It is not possible in mmh to override the automatic MIME type guessing
|
|
meillo@102
|
2074 for a specific file.
|
|
meillo@159
|
2075 To do so, either the user would need to know in advance for which file
|
|
meillo@159
|
2076 the automatic guessing fails, or the system would require interaction.
|
|
meillo@102
|
2077 I consider both cases impractical.
|
|
meillo@102
|
2078 The existing solution should be sufficient.
|
|
meillo@102
|
2079 If not, the user may always fall back to
|
|
meillo@102
|
2080 .Pn mhbuild
|
|
meillo@102
|
2081 composition drafts and ignore the attachment system.
|
|
meillo@101
|
2082
|
|
meillo@102
|
2083
|
|
meillo@102
|
2084 .U3 "Storing Attachments
|
|
meillo@102
|
2085 .P
|
|
meillo@108
|
2086 Extracting MIME parts of a message and storing them to disk is done by
|
|
meillo@108
|
2087 .Pn mhstore .
|
|
meillo@108
|
2088 The program has two operation modes,
|
|
meillo@108
|
2089 .Sw -auto
|
|
meillo@108
|
2090 and
|
|
meillo@108
|
2091 .Sw -noauto .
|
|
meillo@108
|
2092 With the former one, each part is stored under the filename given in the
|
|
meillo@108
|
2093 MIME part's meta information, if available.
|
|
meillo@108
|
2094 This naming information is usually available for modern attachments.
|
|
meillo@108
|
2095 If no filename is available, this MIME part is stored as if
|
|
meillo@108
|
2096 .Sw -noauto
|
|
meillo@108
|
2097 would have been specified.
|
|
meillo@108
|
2098 In the
|
|
meillo@108
|
2099 .Sw -noauto
|
|
meillo@108
|
2100 mode, the parts are processed according to rules, defined by
|
|
meillo@108
|
2101 .Pe mhstore-store-*
|
|
meillo@108
|
2102 profile entries.
|
|
meillo@108
|
2103 These rules define generic filename templates for storing
|
|
meillo@108
|
2104 or commands to post-process the contents in arbitrary ways.
|
|
meillo@108
|
2105 If no matching rule is available the part is stored under a generic
|
|
meillo@108
|
2106 filename, built from message number, MIME part number, and MIME type.
|
|
meillo@108
|
2107 .P
|
|
meillo@108
|
2108 The
|
|
meillo@108
|
2109 .Sw -noauto
|
|
meillo@108
|
2110 mode had been the default in nmh because it was considered safe,
|
|
meillo@108
|
2111 in contrast to the
|
|
meillo@108
|
2112 .Sw -auto
|
|
meillo@108
|
2113 mode.
|
|
meillo@108
|
2114 In mmh,
|
|
meillo@108
|
2115 .Sw -auto
|
|
meillo@108
|
2116 is not dangerous anymore.
|
|
meillo@108
|
2117 Two changes were necessary:
|
|
meillo@108
|
2118 .BU
|
|
meillo@108
|
2119 Any directory path is removed from the proposed filename.
|
|
meillo@108
|
2120 Thus, the files are always stored in the expected directory.
|
|
meillo@108
|
2121 .Ci 41b6eadbcecf63c9a66aa5e582011987494abefb
|
|
meillo@108
|
2122 .BU
|
|
meillo@108
|
2123 Tar files are not extracted automatically any more.
|
|
meillo@108
|
2124 Thus, the rest of the file system will not be touched.
|
|
meillo@108
|
2125 .Ci 94c80042eae3383c812d9552089953f9846b1bb6
|
|
meillo@108
|
2126 .LP
|
|
meillo@108
|
2127 Now, the outcome of mmh's
|
|
meillo@108
|
2128 .Cl "mhstore -auto
|
|
meillo@110
|
2129 can be foreseen from the output of
|
|
meillo@108
|
2130 .Cl "mhlist -verbose" .
|
|
meillo@108
|
2131 .P
|
|
meillo@108
|
2132 The
|
|
meillo@108
|
2133 .Sw -noauto
|
|
meillo@108
|
2134 mode is seen to be more powerful but less convenient.
|
|
meillo@108
|
2135 On the other hand,
|
|
meillo@108
|
2136 .Sw -auto
|
|
meillo@108
|
2137 is safe now and
|
|
meillo@108
|
2138 storing attachments under their original name is intuitive.
|
|
meillo@108
|
2139 Hence,
|
|
meillo@108
|
2140 .Sw -auto
|
|
meillo@108
|
2141 serves better as the default option.
|
|
meillo@108
|
2142 .Ci 3410b680416c49a7617491af38bc1929855a331d
|
|
meillo@108
|
2143 .P
|
|
meillo@108
|
2144 Files are stored into the directory given by the
|
|
meillo@108
|
2145 .Pe Nmh-Storage
|
|
meillo@108
|
2146 profile entry, if set, or
|
|
meillo@108
|
2147 into the current working directory, otherwise.
|
|
meillo@108
|
2148 Storing to different directories is only possible with
|
|
meillo@108
|
2149 .Pe mhstore-store-*
|
|
meillo@108
|
2150 profile entries.
|
|
meillo@108
|
2151 .P
|
|
meillo@108
|
2152 Still, in both modes, existing files get overwritten silently.
|
|
meillo@108
|
2153 This can be considered a bug.
|
|
meillo@108
|
2154 Yet, each other behavior has its draw-backs, too.
|
|
meillo@108
|
2155 Refusing to replace files requires adding a
|
|
meillo@108
|
2156 .Sw -force
|
|
meillo@108
|
2157 option.
|
|
meillo@108
|
2158 Users will likely need to invoke
|
|
meillo@108
|
2159 .Pn mhstore
|
|
meillo@108
|
2160 a second time with
|
|
meillo@159
|
2161 .Sw -force .
|
|
meillo@159
|
2162 Eventually, only the user can decide in the specific case.
|
|
meillo@108
|
2163 This requires interaction, which I like to avoid if possible.
|
|
meillo@108
|
2164 Appending a unique suffix to the filename is another bad option.
|
|
meillo@108
|
2165 For now, the behavior remains as it is.
|
|
meillo@108
|
2166 .P
|
|
meillo@108
|
2167 In mmh, only MIME parts of type message are special in
|
|
meillo@108
|
2168 .Pn mhstore 's
|
|
meillo@108
|
2169 .Sw -auto
|
|
meillo@108
|
2170 mode.
|
|
meillo@108
|
2171 Instead of storing message/rfc822 parts as files to disk,
|
|
meillo@108
|
2172 they are stored as messages into the current mail folder.
|
|
meillo@159
|
2173 The same applies to message/partial, although the parts are
|
|
meillo@159
|
2174 automatically reassembled beforehand.
|
|
meillo@159
|
2175 MIME parts of type message/external-body are not automatically retrieved
|
|
meillo@159
|
2176 anymore.
|
|
meillo@159
|
2177 Instead, information on how to retrieve them is output.
|
|
meillo@108
|
2178 Not supporting this rare case saved nearly one thousand lines of code.
|
|
meillo@108
|
2179 .Ci 55e1d8c654ee0f7c45b9361ce34617983b454c32
|
|
meillo@108
|
2180 .\" XXX mention somewhere else too: (The profile entry `nmh-access-ftp'
|
|
meillo@108
|
2181 .\" and sbr/ruserpass.c for reading ~/.netrc are gone now.)
|
|
meillo@159
|
2182 `application/octet-stream; type=tar' is not special anymore.
|
|
meillo@108
|
2183 Automatically extracting such MIME parts had been the dangerous part
|
|
meillo@108
|
2184 of the
|
|
meillo@108
|
2185 .Sw -auto
|
|
meillo@108
|
2186 mode.
|
|
meillo@108
|
2187 .Ci 94c80042eae3383c812d9552089953f9846b1bb6
|
|
meillo@108
|
2188
|
|
meillo@102
|
2189
|
|
meillo@102
|
2190
|
|
meillo@102
|
2191 .U3 "Showing MIME Messages
|
|
meillo@102
|
2192 .P
|
|
meillo@114
|
2193 The program
|
|
meillo@114
|
2194 .Pn mhshow
|
|
meillo@114
|
2195 had been written to display MIME messages.
|
|
meillo@114
|
2196 It implemented the conceptional view of the MIME RFCs.
|
|
meillo@114
|
2197 Nmh's
|
|
meillo@114
|
2198 .Pn mhshow
|
|
meillo@114
|
2199 handled each MIME part independently, presenting them separately
|
|
meillo@114
|
2200 to the user.
|
|
meillo@114
|
2201 This does not match today's understanding of email attachments,
|
|
meillo@114
|
2202 where displaying a message is seen to be a single, integrated operation.
|
|
meillo@114
|
2203 Today, email messages are expected to consist of a main text part
|
|
meillo@114
|
2204 plus possibly attachments.
|
|
meillo@114
|
2205 They are not any more seen to be arbitrary MIME hierarchies with
|
|
meillo@114
|
2206 information on how to display the individual parts.
|
|
meillo@114
|
2207 I adjusted
|
|
meillo@114
|
2208 .Pn mhshow 's
|
|
meillo@114
|
2209 behavior to the modern view on the topic.
|
|
meillo@114
|
2210 .P
|
|
meillo@159
|
2211 One should note that this section completely ignores the original
|
|
meillo@114
|
2212 .Pn show
|
|
meillo@114
|
2213 program, because it was not capable to display MIME messages
|
|
meillo@114
|
2214 and is no longer part of mmh.
|
|
meillo@114
|
2215 Although
|
|
meillo@114
|
2216 .Pn mhshow
|
|
meillo@114
|
2217 was renamed to
|
|
meillo@114
|
2218 .Pn show
|
|
meillo@114
|
2219 in mmh, this section uses the name
|
|
meillo@114
|
2220 .Pn mhshow ,
|
|
meillo@114
|
2221 in order to avoid confusion.
|
|
meillo@159
|
2222 .\" XXX ref to other section
|
|
meillo@114
|
2223 .P
|
|
meillo@114
|
2224 In mmh, the basic idea is that
|
|
meillo@114
|
2225 .Pn mhshow
|
|
meillo@114
|
2226 should display a message in one single pager session.
|
|
meillo@114
|
2227 Therefore,
|
|
meillo@114
|
2228 .Pn mhshow
|
|
meillo@114
|
2229 invokes a pager session for all its output,
|
|
meillo@114
|
2230 whenever it prints to a terminal.
|
|
meillo@114
|
2231 .Ci a4197ea6ffc5c1550e8b52d5a654bcaaaee04a4e
|
|
meillo@114
|
2232 In consequence,
|
|
meillo@114
|
2233 .Pn mhl
|
|
meillo@114
|
2234 does no more invoke a pager.
|
|
meillo@114
|
2235 .Ci 0e46503be3c855bddaeae3843e1b659279c35d70
|
|
meillo@114
|
2236 With
|
|
meillo@114
|
2237 .Pn mhshow
|
|
meillo@114
|
2238 replacing the original
|
|
meillo@114
|
2239 .Pn show ,
|
|
meillo@114
|
2240 output from
|
|
meillo@114
|
2241 .Pn mhl
|
|
meillo@114
|
2242 does not go to the terminal directly, but through
|
|
meillo@114
|
2243 .Pn mhshow .
|
|
meillo@114
|
2244 Hence,
|
|
meillo@114
|
2245 .Pn mhl
|
|
meillo@114
|
2246 does not need to invoke a pager.
|
|
meillo@114
|
2247 The one and only job of
|
|
meillo@114
|
2248 .Pn mhl
|
|
meillo@114
|
2249 is to format messages or parts of them.
|
|
meillo@114
|
2250 The only place in mmh, where a pager is invoked is
|
|
meillo@114
|
2251 .Pn mhshow .
|
|
meillo@114
|
2252 .P
|
|
meillo@114
|
2253 .Pe mhshow-show-*
|
|
meillo@114
|
2254 profile entries can be used to display MIME parts in a specific way.
|
|
meillo@114
|
2255 For instance, PDF and Postscript files could be converted to plain text
|
|
meillo@114
|
2256 to display them in the terminal.
|
|
meillo@114
|
2257 In mmh, the displaying of MIME parts will always be done serially.
|
|
meillo@114
|
2258 The request to display the MIME type `multipart/parallel' in parallel
|
|
meillo@114
|
2259 is ignored.
|
|
meillo@114
|
2260 It is simply treated as `multipart/mixed'.
|
|
meillo@114
|
2261 .Ci d0581ba306a7299113a346f9b4c46ce97bc4cef6
|
|
meillo@114
|
2262 This could already be requested with the, now removed,
|
|
meillo@114
|
2263 .Sw -serialonly
|
|
meillo@114
|
2264 switch of
|
|
meillo@114
|
2265 .Pn mhshow .
|
|
meillo@114
|
2266 As MIME parts are always processed exclusively , i.e. serially,
|
|
meillo@114
|
2267 the `%e' escape in
|
|
meillo@114
|
2268 .Pe mhshow-show-*
|
|
meillo@114
|
2269 profile entries became useless and was thus removed.
|
|
meillo@114
|
2270 .Ci a20d405db09b7ccca74d3e8c57550883da49e1ae
|
|
meillo@114
|
2271 .P
|
|
meillo@114
|
2272 In the intended setup, only text content would be displayed.
|
|
meillo@114
|
2273 Non-text content would be converted to text by appropriate
|
|
meillo@114
|
2274 .Pe mhshow-show-*
|
|
meillo@114
|
2275 profile entries before, if possible and wanted.
|
|
meillo@114
|
2276 All output would be displayed in a single pager session.
|
|
meillo@114
|
2277 Other kinds of attachments are ignored.
|
|
meillo@114
|
2278 With
|
|
meillo@114
|
2279 .Pe mhshow-show-*
|
|
meillo@114
|
2280 profile entries for them, they can be displayed serially along
|
|
meillo@114
|
2281 the message.
|
|
meillo@114
|
2282 For parallel display, the attachments need to be stored to disk first.
|
|
meillo@114
|
2283 .P
|
|
meillo@114
|
2284 To display text content in foreign charsets, they need to be converted
|
|
meillo@114
|
2285 to the native charset.
|
|
meillo@114
|
2286 Therefore,
|
|
meillo@114
|
2287 .Pe mhshow-charset-*
|
|
meillo@114
|
2288 profile entries used to be needed.
|
|
meillo@121
|
2289 In mmh, the conversion is done automatically by piping the text through
|
|
meillo@114
|
2290 the
|
|
meillo@114
|
2291 .Pn iconv
|
|
meillo@114
|
2292 command, if necessary.
|
|
meillo@114
|
2293 .Ci 2433122c20baccb10b70b49c04c6b0497b5b3b60
|
|
meillo@114
|
2294 Custom
|
|
meillo@114
|
2295 .Pe mhshow-show-*
|
|
meillo@114
|
2296 rules for textual content might need a
|
|
meillo@114
|
2297 .Cl "iconv -f %c %f |
|
|
meillo@114
|
2298 prefix to have the text converted to the native charset.
|
|
meillo@114
|
2299 .P
|
|
meillo@121
|
2300 Although the conversion of foreign charsets to the native one
|
|
meillo@114
|
2301 has improved, it is not consistent enough.
|
|
meillo@114
|
2302 Further work needs to be done and
|
|
meillo@114
|
2303 the basic concepts in this field need to be re-thought.
|
|
meillo@114
|
2304 Though, the default setup of mmh displays message in foreign charsets
|
|
meillo@114
|
2305 correctly without the need to configure anything.
|
|
meillo@114
|
2306
|
|
meillo@114
|
2307
|
|
meillo@114
|
2308 .ig
|
|
meillo@114
|
2309
|
|
meillo@114
|
2310 .P
|
|
meillo@114
|
2311 mhshow/mhstore: Removed support for retrieving message/external-body parts.
|
|
meillo@114
|
2312 These tools won't download the contents automatically anymore. Instead,
|
|
meillo@114
|
2313 they print the information needed to get the contents. If someone should
|
|
meillo@114
|
2314 really receive one of those rare message/external-body messages, he can
|
|
meillo@114
|
2315 do the job manually. We save nearly a thousand lines of code. That's worth
|
|
meillo@114
|
2316 it!
|
|
meillo@114
|
2317 (The profile entry `nmh-access-ftp' and sbr/ruserpass.c for reading
|
|
meillo@114
|
2318 ~/.netrc are gone now.)
|
|
meillo@114
|
2319 .Ci 55e1d8c654ee0f7c45b9361ce34617983b454c32
|
|
meillo@114
|
2320
|
|
meillo@114
|
2321 ..
|
|
meillo@102
|
2322
|
|
meillo@58
|
2323
|
|
meillo@58
|
2324
|
|
meillo@58
|
2325 .H2 "Digital Cryptography
|
|
meillo@22
|
2326 .P
|
|
meillo@157
|
2327 Nmh offers no direct support for digital cryptography,
|
|
meillo@157
|
2328 i.e. digital signatures and message encryption.
|
|
meillo@157
|
2329 This functionality needed to be added through third-party software.
|
|
meillo@157
|
2330 In mmh, the functionality should be included because digital
|
|
meillo@157
|
2331 cryptography is a part of modern email and likely used by users of mmh.
|
|
meillo@157
|
2332 A fresh mmh installation should support signing and encrypting
|
|
meillo@157
|
2333 out-of-the-box.
|
|
meillo@157
|
2334 Therefore, Neil Rickert's
|
|
meillo@157
|
2335 .Pn mhsign
|
|
meillo@157
|
2336 and
|
|
meillo@157
|
2337 .Pn mhpgp
|
|
meillo@157
|
2338 scripts
|
|
meillo@157
|
2339 .[
|
|
meillo@157
|
2340 neil rickert mhsign mhpgp
|
|
meillo@157
|
2341 .]
|
|
meillo@157
|
2342 were included into mmh.
|
|
meillo@157
|
2343 The scripts fit well into the mmh, because they are lightweight and
|
|
meillo@157
|
2344 of style similar to the existing tools.
|
|
meillo@157
|
2345 Additionally, no licensing difficulties appeared,
|
|
meillo@157
|
2346 as they are part of the public domain.
|
|
meillo@112
|
2347 .P
|
|
meillo@157
|
2348 The scripts were written for nmh, hence I needed to adjust them according
|
|
meillo@157
|
2349 to the differences of mmh.
|
|
meillo@157
|
2350 For instance, I removed the use of the backup prefix and dropped support
|
|
meillo@157
|
2351 for old PGP features.
|
|
meillo@157
|
2352 .P
|
|
meillo@157
|
2353 .Pn mhsign
|
|
meillo@157
|
2354 handles the signing and encrypting part.
|
|
meillo@157
|
2355 It comprises about 250 lines of shell code and interfaces between
|
|
meillo@157
|
2356 .Pn gnupg
|
|
meillo@157
|
2357 and
|
|
meillo@157
|
2358 the MH system.
|
|
meillo@157
|
2359 It was meant to be invoked at the WhatNow prompt, but in mmh,
|
|
meillo@157
|
2360 .Pn send
|
|
meillo@157
|
2361 does the job automatically.
|
|
meillo@157
|
2362 Special header fields were introduced to request the action.
|
|
meillo@157
|
2363 If a draft contains the
|
|
meillo@157
|
2364 .Hd Sign
|
|
meillo@157
|
2365 header field,
|
|
meillo@157
|
2366 .Pn send
|
|
meillo@157
|
2367 will sign it.
|
|
meillo@157
|
2368 The key to be used is either chosen automatically or specified by the
|
|
meillo@157
|
2369 .Pe Pgpkey
|
|
meillo@157
|
2370 profile entry.
|
|
meillo@157
|
2371 .Pn send
|
|
meillo@157
|
2372 always signes messages using the PGP/MIME standard, \" REF XXX
|
|
meillo@157
|
2373 but by manually invoking
|
|
meillo@157
|
2374 .Pn mhsign ,
|
|
meillo@157
|
2375 old-style non-MIME signatures can be created as well.
|
|
meillo@157
|
2376 To sign an outgoing message, the draft needs to contain a
|
|
meillo@157
|
2377 .Hd Enc
|
|
meillo@157
|
2378 header field.
|
|
meillo@157
|
2379 Public keys of all recipients are taken from the gnupg keyring or
|
|
meillo@157
|
2380 from an overrides files, called
|
|
meillo@157
|
2381 .Fn pgpkeys .
|
|
meillo@157
|
2382 Unless public keys are found for all recipients,
|
|
meillo@157
|
2383 .Pn send
|
|
meillo@157
|
2384 will refuse to encrypt and send it.
|
|
meillo@157
|
2385 Currently, messages with hidden (BCC) recipients can not be encrypted.
|
|
meillo@157
|
2386 This corner-case requires a more complex solution.
|
|
meillo@157
|
2387 Covering it is left to do.
|
|
meillo@157
|
2388 .P
|
|
meillo@157
|
2389 The integrated message signing and encrypting support is one of the
|
|
meillo@157
|
2390 most recent features in mmh.
|
|
meillo@157
|
2391 Feedback from users and the experience I will gather myself
|
|
meillo@157
|
2392 will direct the further development of the facility.
|
|
meillo@157
|
2393 It is worthwhile to consider adding
|
|
meillo@157
|
2394 .Sw -[no]sign
|
|
meillo@157
|
2395 and
|
|
meillo@157
|
2396 .Sw -[no]enc
|
|
meillo@157
|
2397 switches to
|
|
meillo@157
|
2398 .Pn send ,
|
|
meillo@157
|
2399 to override the corresponding header fields.
|
|
meillo@157
|
2400 The profile entry:
|
|
meillo@157
|
2401 .VS
|
|
meillo@157
|
2402 send: -sign
|
|
meillo@157
|
2403 VE
|
|
meillo@157
|
2404 .LP
|
|
meillo@157
|
2405 would then activate signing of all outgoing messages.
|
|
meillo@157
|
2406 With the present approach, the line
|
|
meillo@157
|
2407 .VS
|
|
meillo@157
|
2408 Send:
|
|
meillo@157
|
2409 VE
|
|
meillo@157
|
2410 .LP
|
|
meillo@157
|
2411 needs to be added to all message forms to achieve the same result.
|
|
meillo@157
|
2412 Yet, the integration of
|
|
meillo@157
|
2413 .Pn mhsign
|
|
meillo@157
|
2414 into mmh is too recent to have enough experience to decide this
|
|
meillo@157
|
2415 question now.
|
|
meillo@157
|
2416 .P
|
|
meillo@157
|
2417 .Pn mhpgp
|
|
meillo@157
|
2418 is the contrary part to
|
|
meillo@157
|
2419 .Pn mhsign .
|
|
meillo@157
|
2420 It verifies signatures and decrypts messages.
|
|
meillo@157
|
2421 .P
|
|
meillo@157
|
2422 FIXME: Add it to mmh first, then write about it here.
|
|
meillo@157
|
2423 .P
|
|
meillo@157
|
2424 The integration of
|
|
meillo@157
|
2425 .Pn mhpgp
|
|
meillo@157
|
2426 into
|
|
meillo@157
|
2427 .Pn show ,
|
|
meillo@157
|
2428 to automatically verify signatures and decrypt messages as needed,
|
|
meillo@157
|
2429 is a task left open.
|
|
meillo@157
|
2430 .Pn show 's
|
|
meillo@157
|
2431 current structure does not allow such an integration on basis of
|
|
meillo@157
|
2432 the existing code.
|
|
meillo@157
|
2433 Extensive programming work is required. ... FIXME
|
|
meillo@157
|
2434
|
|
meillo@157
|
2435
|
|
meillo@58
|
2436
|
|
meillo@58
|
2437
|
|
meillo@102
|
2438
|
|
meillo@133
|
2439 .H2 "Draft and Trash Folder
|
|
meillo@131
|
2440 .P
|
|
meillo@58
|
2441
|
|
meillo@131
|
2442 .U3 "Draft Folder
|
|
meillo@154
|
2443 .Id draft-folder
|
|
meillo@131
|
2444 .P
|
|
meillo@131
|
2445 In the beginning, MH had the concept of a draft message.
|
|
meillo@131
|
2446 This is the file
|
|
meillo@131
|
2447 .Fn draft
|
|
meillo@131
|
2448 in the MH directory, which is treated special.
|
|
meillo@131
|
2449 On composing a message, this draft file was used.
|
|
meillo@131
|
2450 As the draft file was one particular file, only one draft could be
|
|
meillo@131
|
2451 managed at any time.
|
|
meillo@131
|
2452 When starting to compose another message before the former one was sent,
|
|
meillo@131
|
2453 the user had to decide among:
|
|
meillo@131
|
2454 .BU
|
|
meillo@131
|
2455 Use the old draft to finish and send it before starting with a new one.
|
|
meillo@131
|
2456 .BU
|
|
meillo@131
|
2457 Discard the old draft, replacing it with the new one.
|
|
meillo@131
|
2458 .BU
|
|
meillo@131
|
2459 Preserve the old draft by refiling it to a folder.
|
|
meillo@131
|
2460 .P
|
|
meillo@131
|
2461 This was, it was only possible to work in alternation on multiple drafts.
|
|
meillo@131
|
2462 Therefore, the current draft needed to be refiled to a folder and
|
|
meillo@131
|
2463 another one re-using for editing.
|
|
meillo@131
|
2464 Working on multiple drafts at the same time was impossible.
|
|
meillo@131
|
2465 The usual approach of switching to a different MH context did not
|
|
meillo@131
|
2466 change anything.
|
|
meillo@131
|
2467 .P
|
|
meillo@131
|
2468 The draft folder facility exists to
|
|
meillo@131
|
2469 allow true parallel editing of drafts, in a straight forward way.
|
|
meillo@131
|
2470 It was introduced by Marshall T. Rose, already in 1984.
|
|
meillo@131
|
2471 Similar to other new features, the draft folder was inactive by default.
|
|
meillo@131
|
2472 Even in nmh, the highly useful draft folder was not available
|
|
meillo@131
|
2473 out-of-the-box.
|
|
meillo@131
|
2474 At least, Richard Coleman added the man page
|
|
meillo@131
|
2475 .Mp mh-draft (5)
|
|
meillo@131
|
2476 to better document the feature.
|
|
meillo@131
|
2477 .P
|
|
meillo@131
|
2478 Not using the draft folder facility has the single advantage of having
|
|
meillo@131
|
2479 the draft file at a static location.
|
|
meillo@131
|
2480 This is simple in simple cases but the concept does not scale for more
|
|
meillo@131
|
2481 complex cases.
|
|
meillo@131
|
2482 The concept of the draft message is too limited for the problem.
|
|
meillo@131
|
2483 Therefore the draft folder was introduced.
|
|
meillo@131
|
2484 It is the more powerful and more natural concept.
|
|
meillo@131
|
2485 The draft folder is a folder like any other folder in MH.
|
|
meillo@131
|
2486 Its messages can be listed like any other messages.
|
|
meillo@131
|
2487 A draft message is no longer a special case.
|
|
meillo@131
|
2488 Tools do not need special switches to work on the draft message.
|
|
meillo@131
|
2489 Hence corner-cases were removed.
|
|
meillo@131
|
2490 .P
|
|
meillo@131
|
2491 The trivial part of the work was activating the draft folder with a
|
|
meillo@131
|
2492 default name.
|
|
meillo@131
|
2493 I chose the name
|
|
meillo@131
|
2494 .Fn +drafts
|
|
meillo@131
|
2495 for obvious reasons.
|
|
meillo@131
|
2496 In consequence, the command line switches
|
|
meillo@131
|
2497 .Sw -draftfolder
|
|
meillo@131
|
2498 and
|
|
meillo@131
|
2499 .Sw -draftmessage
|
|
meillo@131
|
2500 could be removed.
|
|
meillo@131
|
2501 More difficult but also more improving was updating the tools to the
|
|
meillo@131
|
2502 new concept.
|
|
meillo@131
|
2503 For nearly three decades, the tools needed to support two draft handling
|
|
meillo@131
|
2504 approaches.
|
|
meillo@131
|
2505 By fully switching to the draft folder, the tools could be simplified
|
|
meillo@131
|
2506 by dropping the awkward draft message handling code.
|
|
meillo@131
|
2507 .Sw -draft
|
|
meillo@131
|
2508 switches were removed because operating on a draft message is no longer
|
|
meillo@131
|
2509 special.
|
|
meillo@131
|
2510 It became indistinguishable to operating on any other message.
|
|
meillo@131
|
2511 There is no more need to query the user for draft handling.
|
|
meillo@131
|
2512 It is always possible to add another new draft.
|
|
meillo@131
|
2513 Refiling drafts is without difference to refiling other messages.
|
|
meillo@131
|
2514 All these special cases are gone.
|
|
meillo@131
|
2515 Yet, one draft-related switch remained.
|
|
meillo@131
|
2516 .Pn comp
|
|
meillo@131
|
2517 still has
|
|
meillo@131
|
2518 .Sw -[no]use
|
|
meillo@131
|
2519 for switching between two modes:
|
|
meillo@131
|
2520 .BU
|
|
meillo@131
|
2521 .Sw -use :
|
|
meillo@131
|
2522 Modify an existing draft.
|
|
meillo@131
|
2523 .BU
|
|
meillo@131
|
2524 .Sw -nouse :
|
|
meillo@131
|
2525 Compose a new draft, possibly taking some existing message as a form.
|
|
meillo@131
|
2526 .P
|
|
meillo@131
|
2527 In either case, the behavior of
|
|
meillo@131
|
2528 .Pn comp
|
|
meillo@131
|
2529 is deterministic.
|
|
meillo@131
|
2530 .P
|
|
meillo@131
|
2531 .Pn send
|
|
meillo@131
|
2532 now operates on the current message in the draft folder by default.
|
|
meillo@131
|
2533 As message and folder can both be overridden by specifying them on
|
|
meillo@131
|
2534 the command line, it is possible to send any message in the mail storage
|
|
meillo@131
|
2535 by simply specifying its number and folder.
|
|
meillo@131
|
2536 In contrast to the other tools,
|
|
meillo@131
|
2537 .Pn send
|
|
meillo@131
|
2538 takes the draft folder as its default folder.
|
|
meillo@131
|
2539 .P
|
|
meillo@131
|
2540 Dropping the draft message concept in favor for the draft folder concept,
|
|
meillo@131
|
2541 removed special cases with regular cases.
|
|
meillo@131
|
2542 This simplified the source code of the tools, as well as the concepts.
|
|
meillo@131
|
2543 In mmh, draft management does not break with the MH concepts
|
|
meillo@131
|
2544 but applies them.
|
|
meillo@133
|
2545 .Cl "scan +drafts" ,
|
|
meillo@133
|
2546 for instance, is a truly natural request.
|
|
meillo@131
|
2547 Most of the work was already done by Rose in the eighties.
|
|
meillo@133
|
2548 The original improvement of mmh is dropping the old draft message approach
|
|
meillo@133
|
2549 and thus simplifying the tools, the documentation and the system as a whole.
|
|
meillo@131
|
2550 Although my part in the draft handling improvement was small,
|
|
meillo@133
|
2551 it was an important one.
|
|
meillo@131
|
2552
|
|
meillo@131
|
2553
|
|
meillo@131
|
2554 .U3 "Trash Folder
|
|
meillo@154
|
2555 .Id trash-folder
|
|
meillo@131
|
2556 .P
|
|
meillo@131
|
2557 Similar to the situation for drafts is the situation for removed messages.
|
|
meillo@131
|
2558 Historically, a message was ``deleted'' by prepending a specific
|
|
meillo@131
|
2559 \fIbackup prefix\fP, usually the comma character,
|
|
meillo@131
|
2560 to the file name.
|
|
meillo@131
|
2561 The specific message would vanish from MH because only files with
|
|
meillo@131
|
2562 non-digit characters in their name are not treated as messages.
|
|
meillo@131
|
2563 Although files remained in the file system,
|
|
meillo@131
|
2564 the messages were no more visible in MH.
|
|
meillo@131
|
2565 To truly delete them, a maintenance job is needed.
|
|
meillo@131
|
2566 Usually a cron job is installed to delete them after a grace time.
|
|
meillo@131
|
2567 For instance:
|
|
meillo@131
|
2568 .VS
|
|
meillo@131
|
2569 find $HOME/Mail -type f -name ',*' -ctime +7 -delete
|
|
meillo@131
|
2570 VE
|
|
meillo@131
|
2571 In such a setup, the original message can be restored
|
|
meillo@131
|
2572 within the grace time interval by stripping the
|
|
meillo@131
|
2573 the backup prefix from the file name.
|
|
meillo@131
|
2574 But one can not rely on this statement.
|
|
meillo@131
|
2575 If the last message of a folder with six messages (1-6) is removed,
|
|
meillo@131
|
2576 message
|
|
meillo@131
|
2577 .Fn 6 ,
|
|
meillo@131
|
2578 becomes file
|
|
meillo@131
|
2579 .Fn ,6 .
|
|
meillo@131
|
2580 If then a new message enters the same folder, it will be given
|
|
meillo@131
|
2581 the number one higher than the highest existing message.
|
|
meillo@131
|
2582 In this case the message is named
|
|
meillo@131
|
2583 .Fn 6
|
|
meillo@131
|
2584 then.
|
|
meillo@131
|
2585 If this message is removed as well,
|
|
meillo@131
|
2586 then the backup of the former message gets overwritten.
|
|
meillo@131
|
2587 Hence, the ability to restore removed messages does not only depend on
|
|
meillo@131
|
2588 the ``sweeping cron job'' but also on the removing of further messages.
|
|
meillo@131
|
2589 It is undesirable to have such obscure and complex mechanisms.
|
|
meillo@131
|
2590 The user should be given a small set of clear assertions.
|
|
meillo@131
|
2591 ``Removed files are restorable within a seven-day grace time.''
|
|
meillo@131
|
2592 is such a clear assertion.
|
|
meillo@131
|
2593 With the addition ``... unless a message with the same name in the
|
|
meillo@131
|
2594 same folder is removed before.'' the statement becomes complex.
|
|
meillo@131
|
2595 A user will hardly be able to keep track of any removal to know
|
|
meillo@131
|
2596 if the assertion still holds true for a specific file.
|
|
meillo@131
|
2597 The the real mechanism is practically obscure to the user.
|
|
meillo@131
|
2598 The consequences of further removals are not obvious.
|
|
meillo@131
|
2599 .P
|
|
meillo@131
|
2600 Further more, the backup files are scattered within the whole mail storage.
|
|
meillo@131
|
2601 This complicates managing them.
|
|
meillo@131
|
2602 It is possible, with help of
|
|
meillo@131
|
2603 .Pn find ,
|
|
meillo@131
|
2604 but everything would be more convenient
|
|
meillo@131
|
2605 if the deleted messages would be collected in one place.
|
|
meillo@131
|
2606 .P
|
|
meillo@131
|
2607 The profile entry
|
|
meillo@131
|
2608 .Pe rmmproc
|
|
meillo@131
|
2609 (previously named
|
|
meillo@131
|
2610 .Pe Delete-Prog )
|
|
meillo@131
|
2611 was introduced very early to improve the situation.
|
|
meillo@131
|
2612 It could be set to any command, which would be executed to removed
|
|
meillo@131
|
2613 the specified messages.
|
|
meillo@131
|
2614 This would override the default action, described above.
|
|
meillo@131
|
2615 Refiling the to-be-removed files to a garbage folder is the usual example.
|
|
meillo@131
|
2616 Nmh's man page
|
|
meillo@131
|
2617 .Mp rmm (1)
|
|
meillo@131
|
2618 proposes to set the
|
|
meillo@131
|
2619 .Pe rmmproc
|
|
meillo@131
|
2620 to
|
|
meillo@131
|
2621 .Cl "refile +d
|
|
meillo@131
|
2622 to move messages to the garbage folder,
|
|
meillo@131
|
2623 .Fn +d ,
|
|
meillo@131
|
2624 instead of renaming them with the backup prefix.
|
|
meillo@131
|
2625 The man page proposes additionally the expunge command
|
|
meillo@131
|
2626 .Cl "rm `mhpath +d all`
|
|
meillo@131
|
2627 to empty the garbage folder.
|
|
meillo@131
|
2628 .P
|
|
meillo@131
|
2629 Removing messages in such a way has advantages.
|
|
meillo@131
|
2630 The mail storage is prevented from being cluttered with removed messages
|
|
meillo@131
|
2631 because they are all collected in one place.
|
|
meillo@131
|
2632 Existing and removed messages are thus separated more strictly.
|
|
meillo@131
|
2633 No backup files are silently overwritten.
|
|
meillo@131
|
2634 Most important is the ability to keep removed messages in the MH domain.
|
|
meillo@131
|
2635 Messages in the trash folder can be listed like those in any other folder.
|
|
meillo@131
|
2636 Deleted messages can be displayed like any other messages.
|
|
meillo@131
|
2637 Restoring a deleted messages can be done with
|
|
meillo@131
|
2638 .Pn refile .
|
|
meillo@131
|
2639 All operations on deleted files are still covered by the MH tools.
|
|
meillo@131
|
2640 The trash folder is just like any other folder in the mail storage.
|
|
meillo@131
|
2641 .P
|
|
meillo@131
|
2642 Similar to the draft folder case, I dropped the old backup prefix approach
|
|
meillo@131
|
2643 in favor for replacing it by the better suiting trash folder system.
|
|
meillo@131
|
2644 Hence,
|
|
meillo@131
|
2645 .Pn rmm
|
|
meillo@131
|
2646 calls
|
|
meillo@131
|
2647 .Pn refile
|
|
meillo@131
|
2648 to move the to-be-removed message to the trash folder,
|
|
meillo@131
|
2649 .Fn +trash
|
|
meillo@131
|
2650 by default.
|
|
meillo@131
|
2651 To sweep it clean, one can use
|
|
meillo@131
|
2652 .Cl "rmm -unlink +trash a" ,
|
|
meillo@131
|
2653 where the
|
|
meillo@131
|
2654 .Sw -unlink
|
|
meillo@131
|
2655 switch causes the files to be unlinked.
|
|
meillo@131
|
2656 .P
|
|
meillo@131
|
2657 Dropping the legacy approach and completely converting to the new approach
|
|
meillo@131
|
2658 simplified the code base.
|
|
meillo@131
|
2659 The relationship between
|
|
meillo@131
|
2660 .Pn rmm
|
|
meillo@131
|
2661 and
|
|
meillo@131
|
2662 .Pn refile
|
|
meillo@131
|
2663 was inverted.
|
|
meillo@131
|
2664 In mmh,
|
|
meillo@131
|
2665 .Pn rmm
|
|
meillo@131
|
2666 invokes
|
|
meillo@131
|
2667 .Pn refile ,
|
|
meillo@131
|
2668 which used to be the other way round.
|
|
meillo@131
|
2669 Yet, the relationship is simpler now.
|
|
meillo@131
|
2670 No more can loops, like described in nmh's man page for
|
|
meillo@131
|
2671 .Mp refile (1),
|
|
meillo@131
|
2672 occur:
|
|
meillo@131
|
2673 .QS
|
|
meillo@131
|
2674 Since
|
|
meillo@131
|
2675 .Pn refile
|
|
meillo@131
|
2676 uses your
|
|
meillo@131
|
2677 .Pe rmmproc
|
|
meillo@131
|
2678 to delete the message, the
|
|
meillo@131
|
2679 .Pe rmmproc
|
|
meillo@131
|
2680 must NOT call
|
|
meillo@131
|
2681 .Pn refile
|
|
meillo@131
|
2682 without specifying
|
|
meillo@131
|
2683 .Sw -normmproc
|
|
meillo@131
|
2684 or you will create an infinite loop.
|
|
meillo@131
|
2685 .QE
|
|
meillo@131
|
2686 .LP
|
|
meillo@131
|
2687 .Pn rmm
|
|
meillo@131
|
2688 either unlinks a message with
|
|
meillo@131
|
2689 .Fu unlink()
|
|
meillo@131
|
2690 or invokes
|
|
meillo@131
|
2691 .Pn refile
|
|
meillo@131
|
2692 to move it to the trash folder.
|
|
meillo@131
|
2693 .Pn refile
|
|
meillo@131
|
2694 does not invoke any tools.
|
|
meillo@131
|
2695 .P
|
|
meillo@136
|
2696 By generalizing the message removal in the way that it became covered
|
|
meillo@136
|
2697 by the MH concepts made the whole system more powerful.
|
|
meillo@131
|
2698
|
|
meillo@131
|
2699
|
|
meillo@131
|
2700
|
|
meillo@131
|
2701
|
|
meillo@131
|
2702
|
|
meillo@133
|
2703 .H2 "Modern Defaults
|
|
meillo@133
|
2704 .P
|
|
meillo@133
|
2705 Nmh has a bunch of convenience-improving features inactive by default,
|
|
meillo@133
|
2706 although one can expect every new user wanting to have them active.
|
|
meillo@133
|
2707 The reason they are inactive by default is the wish to stay compatible
|
|
meillo@133
|
2708 with old versions.
|
|
meillo@136
|
2709 But what is the definition for old versions?
|
|
meillo@136
|
2710 Still, the highly useful draft folder facility has not been activated
|
|
meillo@136
|
2711 by default although it was introduced over twenty-five years ago.
|
|
meillo@133
|
2712 .[
|
|
meillo@133
|
2713 rose romine real work
|
|
meillo@133
|
2714 .]
|
|
meillo@136
|
2715 The community seems not to care.
|
|
meillo@136
|
2716 This is one of several examples that require new users to first build up
|
|
meillo@136
|
2717 a profile before they can access the modern features of nmh.
|
|
meillo@136
|
2718 Without an extensive profile, the setup is hardly usable
|
|
meillo@133
|
2719 for modern emailing.
|
|
meillo@133
|
2720 The point is not the customization of the setup,
|
|
meillo@136
|
2721 but the need to activate generally useful facilities.
|
|
meillo@133
|
2722 .P
|
|
meillo@133
|
2723 Yet, the real problem lies less in enabling the features, as this is
|
|
meillo@133
|
2724 straight forward as soon as one knows what he wants.
|
|
meillo@133
|
2725 The real problem is that new users need deep insights into the project
|
|
meillo@133
|
2726 before they find out what they are missing and that nmh actually
|
|
meillo@133
|
2727 provides it already, it just was not activated.
|
|
meillo@133
|
2728 To give an example, I needed one year of using nmh
|
|
meillo@133
|
2729 before I became aware of the existence of the attachment system.
|
|
meillo@133
|
2730 One could argue that this fact disqualifies my reading of the
|
|
meillo@133
|
2731 documentation.
|
|
meillo@133
|
2732 If I would have installed nmh from source back then, I could agree.
|
|
meillo@133
|
2733 Yet, I had used a prepackaged version and had expected that it would
|
|
meillo@133
|
2734 just work.
|
|
meillo@133
|
2735 Nevertheless, I had been convinced by the concepts of MH already
|
|
meillo@133
|
2736 and I am a software developer,
|
|
meillo@133
|
2737 still I required a lot of time to discover the cool features.
|
|
meillo@133
|
2738 How can we expect users to be even more advanced than me,
|
|
meillo@133
|
2739 just to allow them use MH in a convenient and modern way?
|
|
meillo@133
|
2740 Unless they are strongly convinced of the concepts, they will fail.
|
|
meillo@133
|
2741 I have seen friends of me giving up disappointed
|
|
meillo@133
|
2742 before they truly used the system,
|
|
meillo@133
|
2743 although they had been motivated in the beginning.
|
|
meillo@133
|
2744 They suffer hard enough to get used to the toolchest approach,
|
|
meillo@133
|
2745 we should spare them further inconveniences.
|
|
meillo@133
|
2746 .P
|
|
meillo@136
|
2747 Maintaining compatibility for its own sake is bad,
|
|
meillo@136
|
2748 because the code base collects more and more compatibility code.
|
|
meillo@136
|
2749 Sticking to the compatiblity code means remaining limited;
|
|
meillo@136
|
2750 not using it renders it unnecessary.
|
|
meillo@136
|
2751 Keeping unused alternative in the code is a bad choice as they likely
|
|
meillo@136
|
2752 gather bugs, by not being well tested.
|
|
meillo@136
|
2753 Also, the increased code size and the greater number of conditions
|
|
meillo@136
|
2754 increase the maintenance costs.
|
|
meillo@133
|
2755 If any MH implementation would be the back-end of widespread
|
|
meillo@133
|
2756 email clients with large user bases, compatibility would be more
|
|
meillo@133
|
2757 important.
|
|
meillo@133
|
2758 Yet, it appears as if this is not the case.
|
|
meillo@133
|
2759 Hence, compatibility is hardly important for technical reasons.
|
|
meillo@133
|
2760 Its importance originates rather from personal reasons.
|
|
meillo@133
|
2761 Nmh's user base is small and old.
|
|
meillo@133
|
2762 Changing the interfaces would cause inconvenience to long-term users of MH.
|
|
meillo@133
|
2763 It would force them to change their many years old MH configurations.
|
|
meillo@133
|
2764 I do understand this aspect, but it keeps new users from using MH.
|
|
meillo@133
|
2765 By sticking to the old users, new users are kept away.
|
|
meillo@133
|
2766 Yet, the future lies in new users.
|
|
meillo@133
|
2767 Hence, mmh invites new users by providing a convenient and modern setup,
|
|
meillo@133
|
2768 readily usable out-of-the-box.
|
|
meillo@133
|
2769 .P
|
|
meillo@136
|
2770 In mmh, all modern features are active by default and many previous
|
|
meillo@136
|
2771 approaches are removed or only accessible in manual ways.
|
|
meillo@136
|
2772 New default features include:
|
|
meillo@133
|
2773 .BU
|
|
meillo@133
|
2774 The attachment system (\c
|
|
meillo@133
|
2775 .Hd Attach ).
|
|
meillo@133
|
2776 .Ci 8ff284ff9167eff8f5349481529332d59ed913b1
|
|
meillo@133
|
2777 .BU
|
|
meillo@133
|
2778 The draft folder facility (\c
|
|
meillo@133
|
2779 .Fn +drafts ).
|
|
meillo@133
|
2780 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@133
|
2781 .BU
|
|
meillo@133
|
2782 The unseen sequence (`u')
|
|
meillo@133
|
2783 .Ci c2360569e1d8d3678e294eb7c1354cb8bf7501c1
|
|
meillo@133
|
2784 and the sequence negation prefix (`!').
|
|
meillo@133
|
2785 .Ci db74c2bd004b2dc9bf8086a6d8bf773ac051f3cc
|
|
meillo@133
|
2786 .BU
|
|
meillo@133
|
2787 Quoting the original message in the reply.
|
|
meillo@133
|
2788 .Ci 67411b1f95d6ec987b4c732459e1ba8a8ac192c6
|
|
meillo@133
|
2789 .BU
|
|
meillo@133
|
2790 Forwarding messages using MIME.
|
|
meillo@133
|
2791 .Ci 6e271608b7b9c23771523f88d23a4d3593010cf1
|
|
meillo@136
|
2792 .P
|
|
meillo@136
|
2793 In consequence, a setup with a profile that defines only the path to the
|
|
meillo@136
|
2794 mail storage, is already convenient to use.
|
|
meillo@136
|
2795 Again, Paul Vixie's ``edginess'' appeal supports the direction I took:
|
|
meillo@136
|
2796 ``the `main branch' should just be modern''.
|
|
meillo@136
|
2797 .[
|
|
meillo@136
|
2798 paul vixie edginess nmh-workers
|
|
meillo@136
|
2799 .]
|
|
meillo@131
|
2800
|
|
meillo@133
|
2801
|
|
meillo@133
|
2802
|
|
meillo@133
|
2803
|
|
meillo@133
|
2804
|
|
meillo@133
|
2805 .\" --------------------------------------------------------------
|
|
meillo@131
|
2806 .H1 "Styling
|
|
meillo@22
|
2807 .P
|
|
meillo@118
|
2808 Kernighan and Pike have emphasized the importance of style in the
|
|
meillo@118
|
2809 preface of their book:
|
|
meillo@118
|
2810 .[ [
|
|
meillo@118
|
2811 kernighan pike practice of programming
|
|
meillo@118
|
2812 .], p. x]
|
|
meillo@118
|
2813 .QS
|
|
meillo@118
|
2814 Chapter 1 discusses programming style.
|
|
meillo@118
|
2815 Good style is so important to good programming that we have chose
|
|
meillo@118
|
2816 to cover it first.
|
|
meillo@118
|
2817 .QE
|
|
meillo@118
|
2818 This section covers changes in mmh that were motivated by the desire
|
|
meillo@118
|
2819 to improve on style.
|
|
meillo@118
|
2820 Many of them follow the rules given in the quoted book.
|
|
meillo@118
|
2821 .[
|
|
meillo@118
|
2822 kernighan pike practice of programming
|
|
meillo@118
|
2823 .]
|
|
meillo@118
|
2824
|
|
meillo@118
|
2825
|
|
meillo@127
|
2826
|
|
meillo@127
|
2827
|
|
meillo@127
|
2828 .H2 "Code Style
|
|
meillo@154
|
2829 .Id code-style
|
|
meillo@118
|
2830 .P
|
|
meillo@118
|
2831 .U3 "Indentation Style
|
|
meillo@118
|
2832 .P
|
|
meillo@118
|
2833 Indentation styles are the holy cow of programmers.
|
|
meillo@118
|
2834 Again Kernighan and Pike:
|
|
meillo@118
|
2835 .[ [
|
|
meillo@118
|
2836 kernighan pike practice of programming
|
|
meillo@118
|
2837 .], p. 10]
|
|
meillo@118
|
2838 .QS
|
|
meillo@118
|
2839 Programmers have always argued about the layout of programs,
|
|
meillo@118
|
2840 but the specific style is much less important than its consistent
|
|
meillo@118
|
2841 application.
|
|
meillo@121
|
2842 Pick one style, preferably ours, use it consistently, and don't waste
|
|
meillo@118
|
2843 time arguing.
|
|
meillo@118
|
2844 .QE
|
|
meillo@118
|
2845 .P
|
|
meillo@118
|
2846 I agree that the constant application is most important,
|
|
meillo@118
|
2847 but I believe that some styles have advantages over others.
|
|
meillo@118
|
2848 For instance the indentation with tab characters only.
|
|
meillo@118
|
2849 Tab characters directly map to the nesting level \(en
|
|
meillo@118
|
2850 one tab, one level.
|
|
meillo@118
|
2851 Tab characters are flexible because developers can adjust them to
|
|
meillo@118
|
2852 whatever width they like to have.
|
|
meillo@118
|
2853 There is no more need to run
|
|
meillo@118
|
2854 .Pn unexpand
|
|
meillo@118
|
2855 or
|
|
meillo@118
|
2856 .Pn entab
|
|
meillo@118
|
2857 programs to ensure the correct mixture of leading tabs and spaces.
|
|
meillo@118
|
2858 The simple rules are: (1) Leading whitespace must consist of tabs only.
|
|
meillo@118
|
2859 (2) Any other whitespace should consist of spaces.
|
|
meillo@121
|
2860 These two rules ensure the integrity of the visual appearance.
|
|
meillo@121
|
2861 Although reformatting existing code should be avoided, I did it.
|
|
meillo@136
|
2862 I did not waste time arguing; I just reformated the code.
|
|
meillo@118
|
2863 .Ci a485ed478abbd599d8c9aab48934e7a26733ecb1
|
|
meillo@118
|
2864
|
|
meillo@118
|
2865 .U3 "Comments
|
|
meillo@118
|
2866 .P
|
|
meillo@118
|
2867 Section 1.6 of
|
|
meillo@118
|
2868 .[ [
|
|
meillo@118
|
2869 kernighan pike practice of programming
|
|
meillo@118
|
2870 .], p. 23]
|
|
meillo@118
|
2871 demands: ``Don't belabor the obvious.''
|
|
meillo@122
|
2872 Hence, I simply removed all the comments in the following code excerpt:
|
|
meillo@118
|
2873 .VS
|
|
meillo@120
|
2874 context_replace(curfolder, folder); /* update current folder */
|
|
meillo@120
|
2875 seq_setcur(mp, mp->lowsel); /* update current message */
|
|
meillo@120
|
2876 seq_save(mp); /* synchronize message sequences */
|
|
meillo@120
|
2877 folder_free(mp); /* free folder/message structure */
|
|
meillo@120
|
2878 context_save(); /* save the context file */
|
|
meillo@120
|
2879
|
|
meillo@120
|
2880 [...]
|
|
meillo@120
|
2881
|
|
meillo@120
|
2882 int c; /* current character */
|
|
meillo@120
|
2883 char *cp; /* miscellaneous character pointer */
|
|
meillo@120
|
2884
|
|
meillo@120
|
2885 [...]
|
|
meillo@120
|
2886
|
|
meillo@120
|
2887 /* NUL-terminate the field */
|
|
meillo@120
|
2888 *cp = '\0';
|
|
meillo@118
|
2889 VE
|
|
meillo@120
|
2890 .Ci 426543622b377fc5d091455cba685e114b6df674
|
|
meillo@118
|
2891 .P
|
|
meillo@136
|
2892 The program code explains enough itself, already.
|
|
meillo@136
|
2893
|
|
meillo@118
|
2894
|
|
meillo@118
|
2895 .U3 "Names
|
|
meillo@118
|
2896 .P
|
|
meillo@118
|
2897 Kernighan and Pike suggest:
|
|
meillo@118
|
2898 ``Use active names for functions''.
|
|
meillo@118
|
2899 .[ [
|
|
meillo@118
|
2900 kernighan pike practice of programming
|
|
meillo@118
|
2901 .], p. 4]
|
|
meillo@118
|
2902 One application of this rule was the rename of
|
|
meillo@118
|
2903 .Fu check_charset()
|
|
meillo@118
|
2904 to
|
|
meillo@118
|
2905 .Fu is_native_charset() .
|
|
meillo@118
|
2906 .Ci 8d77b48284c58c135a6b2787e721597346ab056d
|
|
meillo@118
|
2907 The same change fixed a violation of ``Be accurate'' as well.
|
|
meillo@118
|
2908 The code did not match the expectation the function suggested,
|
|
meillo@118
|
2909 as it, for whatever reason, only compared the first ten characters
|
|
meillo@118
|
2910 of the charset name.
|
|
meillo@118
|
2911 .P
|
|
meillo@118
|
2912 More important than using active names is using descriptive names.
|
|
meillo@145
|
2913 .VS
|
|
meillo@145
|
2914 m_unknown(in); /* the MAGIC invocation... */
|
|
meillo@145
|
2915 VE
|
|
meillo@145
|
2916 Renaming the obscure
|
|
meillo@118
|
2917 .Fu m_unknown()
|
|
meillo@145
|
2918 function was a delightful event, although it made the code less funny.
|
|
meillo@118
|
2919 .Ci 611d68d19204d7cbf5bd585391249cb5bafca846
|
|
meillo@118
|
2920 .P
|
|
meillo@118
|
2921 Magic numbers are generally considered bad style.
|
|
meillo@118
|
2922 Obviously, Kernighan and Pike agree:
|
|
meillo@118
|
2923 ``Give names to magic numbers''.
|
|
meillo@118
|
2924 .[ [
|
|
meillo@118
|
2925 kernighan pike practice of programming
|
|
meillo@118
|
2926 .], p. 19]
|
|
meillo@118
|
2927 One such change was naming the type of input \(en mbox or mail folder \(en
|
|
meillo@118
|
2928 to be scanned:
|
|
meillo@118
|
2929 .VS
|
|
meillo@118
|
2930 #define SCN_MBOX (-1)
|
|
meillo@118
|
2931 #define SCN_FOLD 0
|
|
meillo@118
|
2932 VE
|
|
meillo@118
|
2933 .Ci 7ffb36d28e517a6f3a10272056fc127592ab1c19
|
|
meillo@118
|
2934 .P
|
|
meillo@118
|
2935 The argument
|
|
meillo@118
|
2936 .Ar outnum
|
|
meillo@118
|
2937 of the function
|
|
meillo@118
|
2938 .Fu scan()
|
|
meillo@118
|
2939 in
|
|
meillo@118
|
2940 .Fn uip/scansbr.c
|
|
meillo@118
|
2941 defines the number of the message to be created.
|
|
meillo@118
|
2942 If no message is to be created, the argument is misused to transport
|
|
meillo@118
|
2943 program logic.
|
|
meillo@118
|
2944 This lead to obscure code.
|
|
meillo@118
|
2945 I improved the clarity of the code by introducing two variables:
|
|
meillo@118
|
2946 .VS
|
|
meillo@118
|
2947 int incing = (outnum > 0);
|
|
meillo@118
|
2948 int ismbox = (outnum != 0);
|
|
meillo@118
|
2949 VE
|
|
meillo@118
|
2950 They cover the magic values and are used for conditions.
|
|
meillo@118
|
2951 The variable
|
|
meillo@118
|
2952 .Ar outnum
|
|
meillo@118
|
2953 is only used when it holds an ordinary message number.
|
|
meillo@118
|
2954 .Ci b8b075c77be7794f3ae9ff0e8cedb12b48fd139f
|
|
meillo@118
|
2955 The clarity improvement of the change showed detours in the program logic
|
|
meillo@118
|
2956 of related code parts.
|
|
meillo@118
|
2957 Having the new variables with descriptive names, a more
|
|
meillo@121
|
2958 straight forward implementation became apparent.
|
|
meillo@118
|
2959 Before the clarification was done,
|
|
meillo@118
|
2960 the possibility to improve had not be seen.
|
|
meillo@118
|
2961 .Ci aa60b0ab5e804f8befa890c0a6df0e3143ce0723
|
|
meillo@118
|
2962
|
|
meillo@133
|
2963
|
|
meillo@133
|
2964
|
|
meillo@133
|
2965 .H2 "Structural Rework
|
|
meillo@133
|
2966 .P
|
|
meillo@136
|
2967 Although the stylistic changes described up to here improve the
|
|
meillo@136
|
2968 readability of the source code, all of them are changes ``in the small''.
|
|
meillo@136
|
2969 Structural changes affect a much larger area.
|
|
meillo@136
|
2970 They are more difficult to do but lead to larger improvements,
|
|
meillo@136
|
2971 especially as they influence the outer shape of the tools as well.
|
|
meillo@118
|
2972 .P
|
|
meillo@118
|
2973 At the end of their chapter on style,
|
|
meillo@118
|
2974 Kernighan and Pike ask: ``But why worry about style?''
|
|
meillo@136
|
2975 Following are two examples of structural rework that show
|
|
meillo@136
|
2976 why style is important in the first place.
|
|
meillo@136
|
2977
|
|
meillo@136
|
2978
|
|
meillo@136
|
2979 .U3 "Rework of \f(CWanno\fP
|
|
meillo@118
|
2980 .P
|
|
meillo@120
|
2981 Until 2002,
|
|
meillo@120
|
2982 .Pn anno
|
|
meillo@120
|
2983 had six functional command line switches,
|
|
meillo@120
|
2984 .Sw -component
|
|
meillo@120
|
2985 and
|
|
meillo@120
|
2986 .Sw -text ,
|
|
meillo@120
|
2987 which took an argument each,
|
|
meillo@120
|
2988 and the two pairs of flags,
|
|
meillo@120
|
2989 .Sw -[no]date
|
|
meillo@120
|
2990 and
|
|
meillo@120
|
2991 .Sw -[no]inplace.,
|
|
meillo@120
|
2992 .Sw -component
|
|
meillo@120
|
2993 and
|
|
meillo@120
|
2994 .Sw -text ,
|
|
meillo@120
|
2995 which took an argument each,
|
|
meillo@120
|
2996 and the two pairs of flags,
|
|
meillo@120
|
2997 .Sw -[no]date
|
|
meillo@120
|
2998 and
|
|
meillo@120
|
2999 .Sw -[no]inplace .
|
|
meillo@120
|
3000 Then Jon Steinhart introduced his attachment system.
|
|
meillo@120
|
3001 In need for more advanced annotation handling, he extended
|
|
meillo@120
|
3002 .Pn anno .
|
|
meillo@120
|
3003 He added five more switches:
|
|
meillo@120
|
3004 .Sw -draft ,
|
|
meillo@120
|
3005 .Sw -list ,
|
|
meillo@120
|
3006 .Sw -delete ,
|
|
meillo@120
|
3007 .Sw -append ,
|
|
meillo@120
|
3008 and
|
|
meillo@120
|
3009 .Sw -number ,
|
|
meillo@120
|
3010 the last one taking an argument.
|
|
meillo@121
|
3011 .Ci 7480dbc14bc90f2d872d434205c0784704213252
|
|
meillo@120
|
3012 Later,
|
|
meillo@120
|
3013 .Sw -[no]preserve
|
|
meillo@120
|
3014 was added.
|
|
meillo@121
|
3015 .Ci d9b1d57351d104d7ec1a5621f090657dcce8cb7f
|
|
meillo@120
|
3016 Then, the Synopsis section of the man page
|
|
meillo@120
|
3017 .Mp anno (1)
|
|
meillo@120
|
3018 read:
|
|
meillo@120
|
3019 .VS
|
|
meillo@120
|
3020 anno [+folder] [msgs] [-component field] [-inplace | -noinplace]
|
|
meillo@120
|
3021 [-date | -nodate] [-draft] [-append] [-list] [-delete]
|
|
meillo@120
|
3022 [-number [num|all]] [-preserve | -nopreserve] [-version]
|
|
meillo@120
|
3023 [-help] [-text body]
|
|
meillo@120
|
3024 VE
|
|
meillo@120
|
3025 .LP
|
|
meillo@120
|
3026 The implementation followed the same structure.
|
|
meillo@120
|
3027 Problems became visible when
|
|
meillo@120
|
3028 .Cl "anno -list -number 42
|
|
meillo@120
|
3029 worked on the current message instead on message number 42,
|
|
meillo@120
|
3030 and
|
|
meillo@120
|
3031 .Cl "anno -list -number l:5
|
|
meillo@124
|
3032 did not work on the last five messages but failed with the mysterious
|
|
meillo@120
|
3033 error message: ``anno: missing argument to -list''.
|
|
meillo@121
|
3034 Yet, the invocation matched the specification in the man page.
|
|
meillo@120
|
3035 There, the correct use of
|
|
meillo@120
|
3036 .Sw -number
|
|
meillo@120
|
3037 was defined as being
|
|
meillo@120
|
3038 .Cl "[-number [num|all]]
|
|
meillo@120
|
3039 and the textual description for the combination with
|
|
meillo@120
|
3040 .Sw -list
|
|
meillo@120
|
3041 read:
|
|
meillo@120
|
3042 .QS
|
|
meillo@120
|
3043 The -list option produces a listing of the field bodies for
|
|
meillo@120
|
3044 header fields with names matching the specified component,
|
|
meillo@120
|
3045 one per line. The listing is numbered, starting at 1, if
|
|
meillo@120
|
3046 the -number option is also used.
|
|
meillo@120
|
3047 .QE
|
|
meillo@120
|
3048 .LP
|
|
meillo@120
|
3049 The problem was manifold.
|
|
meillo@120
|
3050 The code required a numeric argument to the
|
|
meillo@120
|
3051 .Sw -number
|
|
meillo@120
|
3052 switch.
|
|
meillo@120
|
3053 If it was missing or non-numeric,
|
|
meillo@120
|
3054 .Pn anno
|
|
meillo@120
|
3055 aborted with an error message that had an off-by-one error,
|
|
meillo@120
|
3056 printing the switch one before the failing one.
|
|
meillo@120
|
3057 Semantically, the argument to the
|
|
meillo@120
|
3058 .Sw -number
|
|
meillo@120
|
3059 switch is only necessary in combination with
|
|
meillo@120
|
3060 .Sw -delete ,
|
|
meillo@120
|
3061 but not with
|
|
meillo@120
|
3062 .Sw -list .
|
|
meillo@120
|
3063 In the former case it is even necessary.
|
|
meillo@120
|
3064 .P
|
|
meillo@120
|
3065 Trying to fix these problems on the surface would not have solved it truly.
|
|
meillo@120
|
3066 The problems discovered originate from a discrepance between the semantic
|
|
meillo@120
|
3067 structure of the problem and the structure implemented in the program.
|
|
meillo@120
|
3068 Such structural differences can not be cured on the surface.
|
|
meillo@120
|
3069 They need to be solved by adjusting the structure of the implementation
|
|
meillo@120
|
3070 to the structure of the problem.
|
|
meillo@120
|
3071 .P
|
|
meillo@120
|
3072 In 2002, the new switches
|
|
meillo@120
|
3073 .Sw -list
|
|
meillo@120
|
3074 and
|
|
meillo@120
|
3075 .Sw -delete
|
|
meillo@120
|
3076 were added in the same way, the
|
|
meillo@120
|
3077 .Sw -number
|
|
meillo@120
|
3078 switch for instance had been added.
|
|
meillo@120
|
3079 Yet, they are of structural different type.
|
|
meillo@120
|
3080 Semantically,
|
|
meillo@120
|
3081 .Sw -list
|
|
meillo@120
|
3082 and
|
|
meillo@120
|
3083 .Sw -delete
|
|
meillo@120
|
3084 introduce modes of operation.
|
|
meillo@120
|
3085 Historically,
|
|
meillo@120
|
3086 .Pn anno
|
|
meillo@120
|
3087 had only one operation mode: adding header fields.
|
|
meillo@120
|
3088 With the extension, it got two moder modes:
|
|
meillo@120
|
3089 listing and deleting header fields.
|
|
meillo@120
|
3090 The structure of the code changes did not pay respect to this
|
|
meillo@120
|
3091 fundamental change to
|
|
meillo@120
|
3092 .Pn anno 's
|
|
meillo@120
|
3093 behavior.
|
|
meillo@120
|
3094 Neither the implementation nor the documentation did clearly
|
|
meillo@120
|
3095 define them as being exclusive modes of operation.
|
|
meillo@120
|
3096 Having identified the problem, I solved it by putting structure into
|
|
meillo@120
|
3097 .Pn anno
|
|
meillo@120
|
3098 and its documentation.
|
|
meillo@120
|
3099 .Ci d54c8db8bdf01e8381890f7729bc0ef4a055ea11
|
|
meillo@120
|
3100 .P
|
|
meillo@120
|
3101 The difference is visible in both, the code and the documentation.
|
|
meillo@121
|
3102 The following code excerpt:
|
|
meillo@120
|
3103 .VS
|
|
meillo@120
|
3104 int delete = -2; /* delete header element if set */
|
|
meillo@120
|
3105 int list = 0; /* list header elements if set */
|
|
meillo@120
|
3106 [...]
|
|
meillo@121
|
3107 case DELETESW: /* delete annotations */
|
|
meillo@121
|
3108 delete = 0;
|
|
meillo@121
|
3109 continue;
|
|
meillo@121
|
3110 case LISTSW: /* produce a listing */
|
|
meillo@121
|
3111 list = 1;
|
|
meillo@121
|
3112 continue;
|
|
meillo@120
|
3113 VE
|
|
meillo@121
|
3114 .LP
|
|
meillo@121
|
3115 was replaced by:
|
|
meillo@120
|
3116 .VS
|
|
meillo@120
|
3117 static enum { MODE_ADD, MODE_DEL, MODE_LIST } mode = MODE_ADD;
|
|
meillo@120
|
3118 [...]
|
|
meillo@121
|
3119 case DELETESW: /* delete annotations */
|
|
meillo@121
|
3120 mode = MODE_DEL;
|
|
meillo@121
|
3121 continue;
|
|
meillo@121
|
3122 case LISTSW: /* produce a listing */
|
|
meillo@121
|
3123 mode = MODE_LIST;
|
|
meillo@121
|
3124 continue;
|
|
meillo@120
|
3125 VE
|
|
meillo@120
|
3126 .LP
|
|
meillo@121
|
3127 The replacement code does not only reflect the problem's structure better,
|
|
meillo@121
|
3128 it is easier to understand as well.
|
|
meillo@121
|
3129 The same applies to the documentation.
|
|
meillo@120
|
3130 The man page was completely reorganized to propagate the same structure.
|
|
meillo@121
|
3131 This is visible in the Synopsis section:
|
|
meillo@120
|
3132 .VS
|
|
meillo@120
|
3133 anno [+folder] [msgs] [-component field] [-text body]
|
|
meillo@120
|
3134 [-append] [-date | -nodate] [-preserve | -nopreserve]
|
|
meillo@120
|
3135 [-Version] [-help]
|
|
meillo@120
|
3136
|
|
meillo@120
|
3137 anno -delete [+folder] [msgs] [-component field] [-text
|
|
meillo@120
|
3138 body] [-number num | all ] [-preserve | -nopreserve]
|
|
meillo@120
|
3139 [-Version] [-help]
|
|
meillo@120
|
3140
|
|
meillo@120
|
3141 anno -list [+folder] [msgs] [-component field] [-number]
|
|
meillo@120
|
3142 [-Version] [-help]
|
|
meillo@120
|
3143 VE
|
|
meillo@121
|
3144 .\" XXX think about explaining the -preserve rework?
|
|
meillo@118
|
3145
|
|
meillo@58
|
3146
|
|
meillo@58
|
3147
|
|
meillo@133
|
3148 .U3 "Path Conversion
|
|
meillo@133
|
3149 .P
|
|
meillo@134
|
3150 Four kinds of path names can appear in MH:
|
|
meillo@134
|
3151 .IP (1)
|
|
meillo@134
|
3152 Absolute Unix directory paths, like
|
|
meillo@134
|
3153 .Fn /etc/passwd .
|
|
meillo@134
|
3154 .IP (2)
|
|
meillo@134
|
3155 Relative Unix directory paths, like
|
|
meillo@134
|
3156 .Fn ./foo/bar .
|
|
meillo@134
|
3157 .IP (3)
|
|
meillo@134
|
3158 Absolute MH folder paths, like
|
|
meillo@134
|
3159 .Fn +friends/phil .
|
|
meillo@134
|
3160 .IP (4)
|
|
meillo@134
|
3161 Relative MH folder paths, like
|
|
meillo@134
|
3162 .Fn @subfolder .
|
|
meillo@134
|
3163 .P
|
|
meillo@134
|
3164 The last type, relative MH folder paths, are hardly documented.
|
|
meillo@134
|
3165 Nonetheless, they are useful for large mail storages.
|
|
meillo@134
|
3166 The current mail folder is specified as `\c
|
|
meillo@134
|
3167 .Fn @ ',
|
|
meillo@134
|
3168 just like the current directory is specified as `\c
|
|
meillo@134
|
3169 .Fn . '.
|
|
meillo@134
|
3170 .P
|
|
meillo@134
|
3171 To allow MH tools to understand all four notations,
|
|
meillo@134
|
3172 they need to convert between them.
|
|
meillo@134
|
3173 In nmh, these path name conversion functions were located in the files
|
|
meillo@134
|
3174 .Fn sbr/path.c
|
|
meillo@134
|
3175 (``return a pathname'') and
|
|
meillo@134
|
3176 .Fn sbr/m_maildir.c
|
|
meillo@134
|
3177 (``get the path for the mail directory'').
|
|
meillo@134
|
3178 The seven functions in the two files were documented with no more
|
|
meillo@134
|
3179 than two comments, which described obvious information.
|
|
meillo@134
|
3180 The function signatures were neither explaining:
|
|
meillo@134
|
3181 .VS
|
|
meillo@134
|
3182 char *path(char *, int);
|
|
meillo@134
|
3183 char *pluspath(char *);
|
|
meillo@134
|
3184 char *m_mailpath(char *);
|
|
meillo@134
|
3185 char *m_maildir(char *);
|
|
meillo@134
|
3186 VE
|
|
meillo@134
|
3187 .P
|
|
meillo@134
|
3188 My investigation provides the following description:
|
|
meillo@134
|
3189 .BU
|
|
meillo@134
|
3190 The second parameter of
|
|
meillo@134
|
3191 .Fu path()
|
|
meillo@134
|
3192 defines the type of path given as first parameter.
|
|
meillo@134
|
3193 Directory paths are converted to absolute directory paths.
|
|
meillo@134
|
3194 Folder paths are converted to absolute folder paths.
|
|
meillo@134
|
3195 Folder paths must not include a leading `@' character.
|
|
meillo@134
|
3196 Leading plus characters are preserved.
|
|
meillo@134
|
3197 The result is a pointer to newly allocated memory.
|
|
meillo@134
|
3198 .BU
|
|
meillo@134
|
3199 .Fu pluspath()
|
|
meillo@134
|
3200 is a convenience-wrapper to
|
|
meillo@134
|
3201 .Fu path() ,
|
|
meillo@134
|
3202 to convert folder paths only.
|
|
meillo@134
|
3203 This function can not be used for directory paths.
|
|
meillo@134
|
3204 An empty string parameter causes a buffer overflow.
|
|
meillo@134
|
3205 .BU
|
|
meillo@134
|
3206 .Fu m_mailpath()
|
|
meillo@134
|
3207 converts directory paths to absolute directory paths.
|
|
meillo@134
|
3208 The characters `+' or `@' at the beginning of the path name are
|
|
meillo@134
|
3209 treated literal, i.e. as the first character of a relative directory path.
|
|
meillo@134
|
3210 Hence, this function can not be used for folder paths.
|
|
meillo@134
|
3211 In any case, the result is an absolute directory path.
|
|
meillo@134
|
3212 The result is a pointer to newly allocated memory.
|
|
meillo@134
|
3213 .BU
|
|
meillo@134
|
3214 .Fu m_maildir()
|
|
meillo@134
|
3215 returns the parameter unchanged if it is an absolute directory path
|
|
meillo@134
|
3216 or begins with the entry `.' or `..'.
|
|
meillo@134
|
3217 All other strings are prepended with the current working directory.
|
|
meillo@134
|
3218 Hence, this functions can not be used for folder paths.
|
|
meillo@134
|
3219 The result is either an absolute directory path or a relative
|
|
meillo@134
|
3220 directory path, starting with a dot.
|
|
meillo@134
|
3221 In contrast to the other functions, the result is a pointer to
|
|
meillo@134
|
3222 static memory.
|
|
meillo@134
|
3223 .P
|
|
meillo@134
|
3224 The situation was obscure, irritating, error-prone, and non-orthogonal.
|
|
meillo@134
|
3225 No clear terminology was used to name the different kinds of path names.
|
|
meillo@134
|
3226 The first argument of
|
|
meillo@134
|
3227 .Fu m_mailpath() ,
|
|
meillo@134
|
3228 for instance, was named
|
|
meillo@134
|
3229 .Ar folder ,
|
|
meillo@134
|
3230 though
|
|
meillo@134
|
3231 .Fu m_mailpath()
|
|
meillo@134
|
3232 can not be used for MH folders.
|
|
meillo@134
|
3233 .P
|
|
meillo@134
|
3234 I reworked the path name conversion completely, introducing clarity.
|
|
meillo@134
|
3235 First of all, the terminology needed to be defined.
|
|
meillo@134
|
3236 A path name is either in the Unix domain, then it is called
|
|
meillo@134
|
3237 \fIdirectory path\fP, `dirpath' for short, or it is in the MH domain,
|
|
meillo@134
|
3238 then it is called \fIfolder path\fP, `folpath' for short.
|
|
meillo@134
|
3239 The two terms need to be used with strict distinction.
|
|
meillo@134
|
3240 Having a clear terminology is often an indicator of having understood
|
|
meillo@134
|
3241 the problem itself.
|
|
meillo@134
|
3242 Second, I exploited the concept of path type indicators.
|
|
meillo@134
|
3243 By requesting every path name to start with a clear type identifier,
|
|
meillo@134
|
3244 conversion between the types can be fully automated.
|
|
meillo@134
|
3245 Thus the tools can accept paths of any type from the user.
|
|
meillo@134
|
3246 Therefore, it was necessary to require relative directory paths to be
|
|
meillo@134
|
3247 prefixed with a dot character.
|
|
meillo@134
|
3248 In consequence, the dot character could no longer be an alias for the
|
|
meillo@134
|
3249 current message.
|
|
meillo@134
|
3250 .Ci cff0e16925e7edbd25b8b9d6d4fbdf03e0e60c01
|
|
meillo@134
|
3251 Third, I created three new functions to replace the previous mess:
|
|
meillo@134
|
3252 .BU
|
|
meillo@134
|
3253 .Fu expandfol()
|
|
meillo@134
|
3254 converts folder paths to absolute folder paths,
|
|
meillo@134
|
3255 without the leading plus character.
|
|
meillo@134
|
3256 Directory paths are simply passed through.
|
|
meillo@134
|
3257 This function is to be used for folder paths only, thus the name.
|
|
meillo@134
|
3258 The result is a pointer to static memory.
|
|
meillo@134
|
3259 .BU
|
|
meillo@134
|
3260 .Fu expanddir()
|
|
meillo@134
|
3261 converts directory paths to absolute directory paths.
|
|
meillo@134
|
3262 Folder paths are treated as relative directory paths.
|
|
meillo@134
|
3263 This function is to be used for directory paths only, thus the name.
|
|
meillo@134
|
3264 The result is a pointer to static memory.
|
|
meillo@134
|
3265 .BU
|
|
meillo@134
|
3266 .Fu toabsdir()
|
|
meillo@134
|
3267 converts any type of path to an absolute directory path.
|
|
meillo@134
|
3268 This is the function of choice for path conversion.
|
|
meillo@134
|
3269 Absolute directory paths are the most general representation of a
|
|
meillo@134
|
3270 path name.
|
|
meillo@134
|
3271 The result is a pointer to static memory.
|
|
meillo@134
|
3272 .P
|
|
meillo@134
|
3273 The new functions have names that indicate their use.
|
|
meillo@134
|
3274 Two of the functions convert relative to absolute path names of the
|
|
meillo@134
|
3275 same type.
|
|
meillo@134
|
3276 The third function converts any path name type to the most general one,
|
|
meillo@134
|
3277 the absolute directory path.
|
|
meillo@134
|
3278 All of the functions return pointers to static memory.
|
|
meillo@134
|
3279 All three functions are implemented in
|
|
meillo@134
|
3280 .Fn sbr/path.c .
|
|
meillo@134
|
3281 .Fn sbr/m_maildir.c
|
|
meillo@134
|
3282 is removed.
|
|
meillo@134
|
3283 .P
|
|
meillo@134
|
3284 Along with the path conversion rework, I also replaced
|
|
meillo@134
|
3285 .Fu getfolder(FDEF)
|
|
meillo@134
|
3286 with
|
|
meillo@134
|
3287 .Fu getdeffol()
|
|
meillo@134
|
3288 and
|
|
meillo@134
|
3289 .Fu getfolder(FCUR)
|
|
meillo@134
|
3290 with
|
|
meillo@134
|
3291 .Fu getcurfol() ,
|
|
meillo@134
|
3292 which is only a convenience wrapper for
|
|
meillo@134
|
3293 .Fu expandfol("@") .
|
|
meillo@134
|
3294 This code was moved from
|
|
meillo@134
|
3295 .Fn sbr/getfolder.c
|
|
meillo@134
|
3296 to
|
|
meillo@134
|
3297 .Fn sbr/path.c .
|
|
meillo@134
|
3298 .P
|
|
meillo@134
|
3299 The related function
|
|
meillo@134
|
3300 .Fu etcpath()
|
|
meillo@134
|
3301 was moved to
|
|
meillo@134
|
3302 .Fn sbr/path.c ,
|
|
meillo@134
|
3303 too.
|
|
meillo@134
|
3304 Previously, it had been located in
|
|
meillo@134
|
3305 .Fn config/config.c ,
|
|
meillo@134
|
3306 for whatever reasons.
|
|
meillo@134
|
3307 .P
|
|
meillo@134
|
3308 .Fn sbr/path.c
|
|
meillo@134
|
3309 now contains all path handling code.
|
|
meillo@134
|
3310 Only 173 lines of code were needed to replace the previous 252 lines.
|
|
meillo@134
|
3311 The readability of the code is highly improved.
|
|
meillo@134
|
3312 Additionally, each of the six exported and one static functions
|
|
meillo@134
|
3313 is introduced by an explaining comment.
|
|
meillo@134
|
3314 .Ci d39e2c447b0d163a5a63f480b23d06edb7a73aa0
|
|
meillo@133
|
3315
|
|
meillo@133
|
3316
|
|
meillo@133
|
3317
|
|
meillo@133
|
3318
|
|
meillo@133
|
3319 .H2 "Profile Reading
|
|
meillo@133
|
3320 .P
|
|
meillo@138
|
3321 The MH profile contains the configuration for the user-specific MH setup.
|
|
meillo@138
|
3322 MH tools read the profile right after starting up,
|
|
meillo@138
|
3323 as it contains the location of the user's mail storage
|
|
meillo@138
|
3324 and similar settings that influence the whole setup.
|
|
meillo@138
|
3325 Further more, the profile contains the default switches for the tools,
|
|
meillo@138
|
3326 hence, it must be read before the command line switches are processed.
|
|
meillo@138
|
3327 .P
|
|
meillo@138
|
3328 For historic reasons, some MH tools did not read the profile and context.
|
|
meillo@138
|
3329 Among them were
|
|
meillo@138
|
3330 .Pn post /\c
|
|
meillo@138
|
3331 .Pn spost ,
|
|
meillo@138
|
3332 .Pn mhmail ,
|
|
meillo@138
|
3333 and
|
|
meillo@138
|
3334 .Pn slocal .
|
|
meillo@138
|
3335 The reason why these tools ignored the profile were not clearly stated.
|
|
meillo@138
|
3336 During the discussion on the nmh-workers mailing list,
|
|
meillo@138
|
3337 .[
|
|
meillo@138
|
3338 nmh-workers levine post profile
|
|
meillo@138
|
3339 .]
|
|
meillo@138
|
3340 David Levine posted an explanation, quoting John Romine:
|
|
meillo@138
|
3341 .QS
|
|
meillo@138
|
3342 I asked John Romine and here's what he had to say, which
|
|
meillo@138
|
3343 agrees and provides an example that convinces me:
|
|
meillo@138
|
3344 .QS
|
|
meillo@138
|
3345 My take on this is that post should not be called by
|
|
meillo@138
|
3346 users directly, and it doesn't read the .mh_profile
|
|
meillo@138
|
3347 (only front-end UI programs read the profile).
|
|
meillo@138
|
3348 .QP
|
|
meillo@138
|
3349 For example, there can be contexts where post is called
|
|
meillo@138
|
3350 by a helper program (like 'mhmail') which may be run by
|
|
meillo@138
|
3351 a non-MH user. We don't want this to prompt the user
|
|
meillo@138
|
3352 to create an MH profile, etc.
|
|
meillo@138
|
3353 .QP
|
|
meillo@138
|
3354 My suggestion would be to have send pass a (hidden)
|
|
meillo@138
|
3355 `\-fileproc proc' option to post if needed. You could also
|
|
meillo@138
|
3356 use an environment variable (I think send/whatnow do
|
|
meillo@138
|
3357 this).
|
|
meillo@138
|
3358 .QE
|
|
meillo@138
|
3359 I think that's the way to go. My personal preference is to use a command line option, not an environment variable.
|
|
meillo@138
|
3360 .QE
|
|
meillo@138
|
3361 .P
|
|
meillo@138
|
3362 To solve the problem of
|
|
meillo@138
|
3363 .Pn post
|
|
meillo@138
|
3364 not honoring the
|
|
meillo@138
|
3365 .Pe fileproc
|
|
meillo@138
|
3366 profile entry,
|
|
meillo@138
|
3367 the community roughly agreed that a switch
|
|
meillo@138
|
3368 .Sw -fileproc
|
|
meillo@138
|
3369 should be added to
|
|
meillo@138
|
3370 .Pn post
|
|
meillo@138
|
3371 to be able to pass a different fileproc.
|
|
meillo@138
|
3372 I strongly disagree with this approach because it does not solve
|
|
meillo@138
|
3373 the problem; it only removes a single symptom.
|
|
meillo@138
|
3374 The problem is that
|
|
meillo@138
|
3375 .Pn post
|
|
meillo@138
|
3376 does not behave as expected.
|
|
meillo@138
|
3377 But all programs should behave as expected.
|
|
meillo@138
|
3378 Clear and simple concepts are a precondition for this.
|
|
meillo@138
|
3379 Hence, the real solution is having all MH tools read the profile.
|
|
meillo@138
|
3380 .P
|
|
meillo@138
|
3381 Yet, the problem has a further aspect.
|
|
meillo@138
|
3382 It mainly originates in
|
|
meillo@138
|
3383 .Pn mhmail .
|
|
meillo@138
|
3384 .Pn mhmail
|
|
meillo@138
|
3385 was intended to be a replacement for
|
|
meillo@138
|
3386 .Pn mailx
|
|
meillo@138
|
3387 on systems with MH installations.
|
|
meillo@138
|
3388 .Pn mhmail
|
|
meillo@138
|
3389 should have been able to use just like
|
|
meillo@138
|
3390 .Pn mailx ,
|
|
meillo@138
|
3391 but sending the message via MH's
|
|
meillo@138
|
3392 .Pn post
|
|
meillo@138
|
3393 instead of
|
|
meillo@138
|
3394 .Pn sendmail .
|
|
meillo@138
|
3395 Using
|
|
meillo@138
|
3396 .Pn mhmail
|
|
meillo@138
|
3397 should not be influenced by the question whether the user had
|
|
meillo@138
|
3398 MH set up for himself or not.
|
|
meillo@138
|
3399 .Pn mhmail
|
|
meillo@138
|
3400 did not read the profile as this requests the user to set up MH
|
|
meillo@138
|
3401 if not done yet.
|
|
meillo@138
|
3402 As
|
|
meillo@138
|
3403 .Pn mhmail
|
|
meillo@138
|
3404 used
|
|
meillo@138
|
3405 .Pn post ,
|
|
meillo@138
|
3406 .Pn post
|
|
meillo@138
|
3407 could not read the profile neither.
|
|
meillo@138
|
3408 This is the reason why
|
|
meillo@138
|
3409 .Pn post
|
|
meillo@138
|
3410 does not read the profile.
|
|
meillo@138
|
3411 This is the reason for the actual problem.
|
|
meillo@138
|
3412 It was not much of a problem because
|
|
meillo@138
|
3413 .Pn post
|
|
meillo@138
|
3414 was not intended to be used by users directly.
|
|
meillo@138
|
3415 .Pn send
|
|
meillo@138
|
3416 is the interactive front-end to
|
|
meillo@138
|
3417 .Pn post .
|
|
meillo@138
|
3418 .Pn send
|
|
meillo@138
|
3419 read the profile and passed all relevant values on the command line to
|
|
meillo@138
|
3420 .Pn post
|
|
meillo@138
|
3421 \(en an awkward solution.
|
|
meillo@138
|
3422 .P
|
|
meillo@138
|
3423 The important insight is that
|
|
meillo@138
|
3424 .Pn mhmail
|
|
meillo@138
|
3425 is no true MH tool.
|
|
meillo@138
|
3426 The concepts broke because this outlandish tool was treated as any other
|
|
meillo@138
|
3427 MH tool.
|
|
meillo@138
|
3428 Instead it should have been treated accordingly to its foreign style.
|
|
meillo@138
|
3429 The solution is not to prevent the tools reading the profile but
|
|
meillo@138
|
3430 to instruct them reading a different profile.
|
|
meillo@138
|
3431 .Pn mhmail
|
|
meillo@138
|
3432 could have set up a well-defined profile and caused all MH tools
|
|
meillo@138
|
3433 in the session use it by exporting an environment variable.
|
|
meillo@138
|
3434 With this approach, no special cases would have been introduced,
|
|
meillo@138
|
3435 no surprises would have been caused.
|
|
meillo@138
|
3436 By writing a clean-profile-wrapper, the concept could have been
|
|
meillo@138
|
3437 generalized orthogonally to the whole MH toolchest.
|
|
meillo@138
|
3438 Then Rose's motivation behind the decision that
|
|
meillo@138
|
3439 .Pn post
|
|
meillo@138
|
3440 ignores the profile, as quoted by Jeffrey Honig,
|
|
meillo@138
|
3441 .[
|
|
meillo@138
|
3442 nmh-workers post profile
|
|
meillo@138
|
3443 .]
|
|
meillo@138
|
3444 would have become possible:
|
|
meillo@138
|
3445 .QS
|
|
meillo@138
|
3446 when you run mh commands in a script, you want all the defaults to be
|
|
meillo@138
|
3447 what the man page says.
|
|
meillo@138
|
3448 when you run a command by hand, then you want your own defaults...
|
|
meillo@138
|
3449 .QE
|
|
meillo@138
|
3450 .LP
|
|
meillo@138
|
3451 Yet, I consider this explanation short-sighted.
|
|
meillo@138
|
3452 We should rather regard theses two cases as just two different MH setups,
|
|
meillo@138
|
3453 based on two different profiles.
|
|
meillo@138
|
3454 Mapping such problems on the concepts of switching between different
|
|
meillo@138
|
3455 profiles, solves them once for all.
|
|
meillo@138
|
3456 .P
|
|
meillo@138
|
3457 In mmh, the wish to have
|
|
meillo@138
|
3458 .Pn mhmail
|
|
meillo@138
|
3459 as as replacement for
|
|
meillo@138
|
3460 .Pn mailx
|
|
meillo@138
|
3461 is considered obsolete.
|
|
meillo@138
|
3462 Mmh's
|
|
meillo@138
|
3463 .Pn mhmail
|
|
meillo@138
|
3464 does no longer cover this use-case.
|
|
meillo@138
|
3465 Currently,
|
|
meillo@138
|
3466 .Pn mhmail
|
|
meillo@138
|
3467 is in a transition state.
|
|
meillo@138
|
3468 .Ci 32d4f9daaa70519be3072479232ff7be0500d009
|
|
meillo@138
|
3469 It may become a front-end to
|
|
meillo@138
|
3470 .Pn comp ,
|
|
meillo@138
|
3471 which provides an interface more convenient in some cases.
|
|
meillo@138
|
3472 In this case,
|
|
meillo@138
|
3473 .Pn mhmail
|
|
meillo@138
|
3474 will become an ordinary MH tool, reading the profile.
|
|
meillo@138
|
3475 If, however, this idea will not convince, then
|
|
meillo@138
|
3476 .Pn mhmail
|
|
meillo@138
|
3477 will be removed.
|
|
meillo@138
|
3478 .P
|
|
meillo@138
|
3479 Every program in the mmh toolchest reads the profile.
|
|
meillo@138
|
3480 The only exception is
|
|
meillo@138
|
3481 .Pn slocal ,
|
|
meillo@138
|
3482 which is not considered part of the mmh toolchest.
|
|
meillo@138
|
3483 This MDA is only distributed with mmh, currently.
|
|
meillo@138
|
3484 Mmh has no
|
|
meillo@138
|
3485 .Pn post
|
|
meillo@138
|
3486 program, but
|
|
meillo@138
|
3487 .Pn spost ,
|
|
meillo@138
|
3488 which now reads the profile.
|
|
meillo@138
|
3489 .Ci 3e017a7abbdf69bf0dff7a4073275961eda1ded8
|
|
meillo@138
|
3490 With this change,
|
|
meillo@138
|
3491 .Pn send
|
|
meillo@138
|
3492 and
|
|
meillo@138
|
3493 .Pn spost
|
|
meillo@138
|
3494 can be considered to be merged.
|
|
meillo@138
|
3495 Direct invocations of
|
|
meillo@138
|
3496 .Pn spost
|
|
meillo@138
|
3497 are only done by the to-be-changed
|
|
meillo@138
|
3498 .Pn mhmail
|
|
meillo@138
|
3499 implementation and by
|
|
meillo@138
|
3500 .Pn rcvdist ,
|
|
meillo@138
|
3501 which will require rework.
|
|
meillo@138
|
3502 .P
|
|
meillo@138
|
3503 The
|
|
meillo@138
|
3504 .Fu context_foil()
|
|
meillo@138
|
3505 function to pretend to have read an empty profile was removed.
|
|
meillo@138
|
3506 .Ci 68af8da96bea87a5541988870130b6209ce396f6
|
|
meillo@138
|
3507 All mmh tools read the profile.
|
|
meillo@133
|
3508
|
|
meillo@133
|
3509
|
|
meillo@127
|
3510
|
|
meillo@121
|
3511 .H2 "Standard Libraries
|
|
meillo@22
|
3512 .P
|
|
meillo@121
|
3513 MH is one decade older than the POSIX and ANSI C standards.
|
|
meillo@121
|
3514 Hence, MH included own implementations of functions
|
|
meillo@121
|
3515 that are standardized and thus widely available today,
|
|
meillo@121
|
3516 but were not back then.
|
|
meillo@121
|
3517 Today, twenty years after the POSIX and ANSI C were published,
|
|
meillo@121
|
3518 developers can expect system to comply with these standards.
|
|
meillo@121
|
3519 In consequence, MH-specific replacements for standard functions
|
|
meillo@121
|
3520 can and should be dropped.
|
|
meillo@121
|
3521 Kernighan and Pike advise: ``Use standard libraries.''
|
|
meillo@121
|
3522 .[ [
|
|
meillo@121
|
3523 kernighan pike practice of programming
|
|
meillo@121
|
3524 .], p. 196]
|
|
meillo@121
|
3525 Actually, MH had followed this advice in history,
|
|
meillo@121
|
3526 but it had not adjusted to the changes in this field.
|
|
meillo@121
|
3527 The
|
|
meillo@121
|
3528 .Fu snprintf()
|
|
meillo@121
|
3529 function, for instance, was standardized with C99 and is available
|
|
meillo@121
|
3530 almost everywhere because of its high usefulness.
|
|
meillo@123
|
3531 In project's own implementation of
|
|
meillo@121
|
3532 .Fu snprintf()
|
|
meillo@123
|
3533 was dropped in March 2012 in favor for using the one of the
|
|
meillo@123
|
3534 standard library.
|
|
meillo@123
|
3535 .Ci 0052f1024deb0a0a2fc2e5bacf93d45a5a9c9b32
|
|
meillo@123
|
3536 Such decisions limit the portability of mmh
|
|
meillo@121
|
3537 if systems don't support these standardized and widespread functions.
|
|
meillo@123
|
3538 This compromise is made because mmh focuses on the future.
|
|
meillo@121
|
3539 .P
|
|
meillo@123
|
3540 I am not yet thirty years old and my C and Unix experience comprises
|
|
meillo@123
|
3541 only half a dozen years.
|
|
meillo@121
|
3542 Hence, I need to learn about the history in retrospective.
|
|
meillo@121
|
3543 I have not used those ancient constructs myself.
|
|
meillo@121
|
3544 I have not suffered from their incompatibilities.
|
|
meillo@121
|
3545 I have not longed for standardization.
|
|
meillo@121
|
3546 All my programming experience is from a time when ANSI C and POSIX
|
|
meillo@121
|
3547 were well established already.
|
|
meillo@121
|
3548 I have only read a lot of books about the (good) old times.
|
|
meillo@121
|
3549 This puts me in a difficult positions when working with old code.
|
|
meillo@123
|
3550 I need to freshly acquire knowledge about old code constructs and ancient
|
|
meillo@123
|
3551 programming styles, whereas older programmers know these things by
|
|
meillo@123
|
3552 heart from their own experience.
|
|
meillo@121
|
3553 .P
|
|
meillo@123
|
3554 Being aware of the situation, I rather let people with more historic
|
|
meillo@123
|
3555 experience replace ancient code constructs with standardized ones.
|
|
meillo@121
|
3556 Lyndon Nerenberg covered large parts of this task for the nmh project.
|
|
meillo@121
|
3557 He converted project-specific functions to POSIX replacements,
|
|
meillo@121
|
3558 also removing the conditionals compilation of now standardized features.
|
|
meillo@123
|
3559 Ken Hornstein and David Levine had their part in the work, too.
|
|
meillo@121
|
3560 Often, I only needed to pull over changes from nmh into mmh.
|
|
meillo@121
|
3561 These changes include many commits; these are among them:
|
|
meillo@121
|
3562 .Ci 768b5edd9623b7238e12ec8dfc409b82a1ed9e2d
|
|
meillo@121
|
3563 .Ci 0052f1024deb0a0a2fc2e5bacf93d45a5a9c9b32 .
|
|
meillo@102
|
3564 .P
|
|
meillo@123
|
3565 During my own work, I tidied up the \fIMH standard library\fP,
|
|
meillo@123
|
3566 .Fn libmh.a ,
|
|
meillo@123
|
3567 which is located in the
|
|
meillo@123
|
3568 .Fn sbr
|
|
meillo@123
|
3569 (``subroutines'') directory in the source tree.
|
|
meillo@123
|
3570 The MH library includes functions that mmh tools usually need.
|
|
meillo@123
|
3571 Among them are MH-specific functions for profile, context, sequence,
|
|
meillo@123
|
3572 and folder handling, but as well
|
|
meillo@123
|
3573 MH-independent functions, such as auxiliary string functions,
|
|
meillo@123
|
3574 portability interfaces and error-checking wrappers for critical
|
|
meillo@123
|
3575 functions of the standard library.
|
|
meillo@123
|
3576 .P
|
|
meillo@123
|
3577 I have replaced the
|
|
meillo@121
|
3578 .Fu atooi()
|
|
meillo@121
|
3579 function with calls to
|
|
meillo@123
|
3580 .Fu strtoul()
|
|
meillo@139
|
3581 with the third parameter, the base, set to eight.
|
|
meillo@121
|
3582 .Fu strtoul()
|
|
meillo@123
|
3583 is part of C89 and thus considered safe to use.
|
|
meillo@121
|
3584 .Ci c490c51b3c0f8871b6953bd0c74551404f840a74
|
|
meillo@102
|
3585 .P
|
|
meillo@121
|
3586 I did remove project-included fallback implementations of
|
|
meillo@121
|
3587 .Fu memmove()
|
|
meillo@121
|
3588 and
|
|
meillo@121
|
3589 .Fu strerror() ,
|
|
meillo@121
|
3590 although Peter Maydell had re-included them into nmh in 2008
|
|
meillo@121
|
3591 to support SunOS 4.
|
|
meillo@121
|
3592 Nevertheless, these functions are part of ANSI C.
|
|
meillo@121
|
3593 Systems that do not even provide full ANSI C support should not
|
|
meillo@121
|
3594 put a load on mmh.
|
|
meillo@121
|
3595 .Ci b067ff5c465a5d243ce5a19e562085a9a1a97215
|
|
meillo@121
|
3596 .P
|
|
meillo@121
|
3597 The
|
|
meillo@121
|
3598 .Fu copy()
|
|
meillo@121
|
3599 function copies the string in argument one to the location in two.
|
|
meillo@121
|
3600 In contrast to
|
|
meillo@121
|
3601 .Fu strcpy() ,
|
|
meillo@121
|
3602 it returns a pointer to the terminating null-byte in the destination area.
|
|
meillo@123
|
3603 The code was adjusted to replace
|
|
meillo@121
|
3604 .Fu copy()
|
|
meillo@123
|
3605 with
|
|
meillo@121
|
3606 .Fu strcpy() ,
|
|
meillo@121
|
3607 except within
|
|
meillo@121
|
3608 .Fu concat() ,
|
|
meillo@121
|
3609 where
|
|
meillo@121
|
3610 .Fu copy()
|
|
meillo@123
|
3611 was more convenient.
|
|
meillo@123
|
3612 Therefore, the definition of
|
|
meillo@121
|
3613 .Fu copy()
|
|
meillo@123
|
3614 was moved into the source file of
|
|
meillo@121
|
3615 .Fu concat()
|
|
meillo@123
|
3616 and its visibility is now limited to it.
|
|
meillo@121
|
3617 .Ci 552fd7253e5ee9e554c5c7a8248a6322aa4363bb
|
|
meillo@121
|
3618 .P
|
|
meillo@121
|
3619 The function
|
|
meillo@121
|
3620 .Fu r1bindex()
|
|
meillo@121
|
3621 had been a generalized version of
|
|
meillo@121
|
3622 .Fu basename()
|
|
meillo@121
|
3623 with minor differences.
|
|
meillo@121
|
3624 As all calls to
|
|
meillo@121
|
3625 .Fu r1bindex()
|
|
meillo@121
|
3626 had the slash (`/') as delimiter anyway,
|
|
meillo@121
|
3627 replacing
|
|
meillo@121
|
3628 .Fu r1bindex()
|
|
meillo@121
|
3629 with the more specific and better-named function
|
|
meillo@121
|
3630 .Fu basename()
|
|
meillo@121
|
3631 became desirable.
|
|
meillo@121
|
3632 Unfortunately, many of the 54 calls to
|
|
meillo@121
|
3633 .Fu r1bindex()
|
|
meillo@123
|
3634 depended on a special behavior,
|
|
meillo@121
|
3635 which differed from the POSIX specification for
|
|
meillo@121
|
3636 .Fu basename() .
|
|
meillo@121
|
3637 Hence,
|
|
meillo@121
|
3638 .Fu r1bindex()
|
|
meillo@121
|
3639 was kept but renamed to
|
|
meillo@123
|
3640 .Fu mhbasename() ,
|
|
meillo@123
|
3641 fixing the delimiter to the slash.
|
|
meillo@121
|
3642 .Ci 240013872c392fe644bd4f79382d9f5314b4ea60
|
|
meillo@121
|
3643 For possible uses of
|
|
meillo@121
|
3644 .Fu r1bindex()
|
|
meillo@121
|
3645 with a different delimiter,
|
|
meillo@121
|
3646 the ANSI C function
|
|
meillo@121
|
3647 .Fu strrchr()
|
|
meillo@121
|
3648 provides the core functionality.
|
|
meillo@121
|
3649 .P
|
|
meillo@121
|
3650 The
|
|
meillo@121
|
3651 .Fu ssequal()
|
|
meillo@121
|
3652 function \(en apparently for ``substring equal'' \(en
|
|
meillo@121
|
3653 was renamed to
|
|
meillo@121
|
3654 .Fu isprefix() ,
|
|
meillo@121
|
3655 because this is what it actually checks.
|
|
meillo@121
|
3656 .Ci c20b4fa14515c7ab388ce35411d89a7a92300711
|
|
meillo@121
|
3657 Its source file had included the following comments, no joke.
|
|
meillo@121
|
3658 .VS
|
|
meillo@121
|
3659 /*
|
|
meillo@121
|
3660 * THIS CODE DOES NOT WORK AS ADVERTISED.
|
|
meillo@121
|
3661 * It is actually checking if s1 is a PREFIX of s2.
|
|
meillo@121
|
3662 * All calls to this function need to be checked to see
|
|
meillo@121
|
3663 * if that needs to be changed. Prefix checking is cheaper, so
|
|
meillo@121
|
3664 * should be kept if it's sufficient.
|
|
meillo@121
|
3665 */
|
|
meillo@121
|
3666
|
|
meillo@121
|
3667 /*
|
|
meillo@121
|
3668 * Check if s1 is a substring of s2.
|
|
meillo@121
|
3669 * If yes, then return 1, else return 0.
|
|
meillo@121
|
3670 */
|
|
meillo@121
|
3671 VE
|
|
meillo@123
|
3672 Two months later, it was completely removed by replacing it with
|
|
meillo@123
|
3673 .Fu strncmp() .
|
|
meillo@123
|
3674 .Ci b0b1dd37ff515578cf7cba51625189eb34a196cb
|
|
meillo@121
|
3675
|
|
meillo@102
|
3676
|
|
meillo@102
|
3677
|
|
meillo@102
|
3678
|
|
meillo@133
|
3679
|
|
meillo@133
|
3680 .H2 "User Data Locations
|
|
meillo@133
|
3681 .P
|
|
meillo@133
|
3682 In nmh, a personal setup consists of the MH profile and the MH directory.
|
|
meillo@133
|
3683 The profile is a file named
|
|
meillo@133
|
3684 .Fn \&.mh_profile
|
|
meillo@133
|
3685 in the user's home directory.
|
|
meillo@133
|
3686 It contains the static configuration.
|
|
meillo@133
|
3687 It also contains the location of the MH directory in the profile entry
|
|
meillo@133
|
3688 .Pe Path .
|
|
meillo@133
|
3689 The MH directory contains the mail storage and is the first
|
|
meillo@133
|
3690 place to search for personal forms, scan formats, and similar
|
|
meillo@133
|
3691 configuration files.
|
|
meillo@133
|
3692 The location of the MH directory can be chosen freely by the user.
|
|
meillo@133
|
3693 The default and usual name is a directory named
|
|
meillo@133
|
3694 .Fn Mail
|
|
meillo@133
|
3695 in the home directory.
|
|
meillo@133
|
3696 .P
|
|
meillo@133
|
3697 The way MH data is splitted between profile and MH directory is a legacy.
|
|
meillo@133
|
3698 It is only sensible in a situation where the profile is the only
|
|
meillo@133
|
3699 configuration file.
|
|
meillo@133
|
3700 Why else should the mail storage and the configuration files be intermixed?
|
|
meillo@133
|
3701 They are different kinds of data:
|
|
meillo@133
|
3702 The data to be operated on and the configuration to change how
|
|
meillo@133
|
3703 tools operate.
|
|
meillo@133
|
3704 Splitting the configuration between the profile and the MH directory
|
|
meillo@133
|
3705 is bad.
|
|
meillo@133
|
3706 Merging the mail storage and the configuration in one directory is bad
|
|
meillo@133
|
3707 as well.
|
|
meillo@133
|
3708 As the mail storage and the configuration were not separated sensibly
|
|
meillo@133
|
3709 in the first place, I did it now.
|
|
meillo@133
|
3710 .P
|
|
meillo@133
|
3711 Personal mmh data is grouped by type, resulting in two distinct parts:
|
|
meillo@133
|
3712 The mail storage and the configuration.
|
|
meillo@133
|
3713 In mmh, the mail storage directory still contains all the messages,
|
|
meillo@133
|
3714 but, in exception of public sequences files, nothing else.
|
|
meillo@133
|
3715 In difference to nmh, the auxiliary configuration files are no longer
|
|
meillo@133
|
3716 located there.
|
|
meillo@133
|
3717 Therefore, the directory is no longer called the user's \fIMH directory\fP
|
|
meillo@133
|
3718 but his \fImail storage\fP.
|
|
meillo@133
|
3719 Its location is still user-chosen, with the default name
|
|
meillo@133
|
3720 .Fn Mail ,
|
|
meillo@133
|
3721 in the user's home directory.
|
|
meillo@133
|
3722 In mmh, the configuration is grouped together in
|
|
meillo@133
|
3723 the hidden directory
|
|
meillo@133
|
3724 .Fn \&.mmh
|
|
meillo@133
|
3725 in the user's home directory.
|
|
meillo@133
|
3726 This \fImmh directory\fP contains the context file, personal forms,
|
|
meillo@133
|
3727 scan formats, and the like, but also the user's profile, now named
|
|
meillo@133
|
3728 .Fn profile .
|
|
meillo@133
|
3729 The location of the profile is no longer fixed to
|
|
meillo@133
|
3730 .Fn $HOME/.mh_profile
|
|
meillo@133
|
3731 but to
|
|
meillo@133
|
3732 .Fn $HOME/.mmh/profile .
|
|
meillo@133
|
3733 Having both, the file
|
|
meillo@133
|
3734 .Fn $HOME/.mh_profile
|
|
meillo@133
|
3735 and the configuration directory
|
|
meillo@133
|
3736 .Fn $HOME/.mmh
|
|
meillo@133
|
3737 appeared to be inconsistent.
|
|
meillo@133
|
3738 The approach chosen for mmh is consistent, simple, and familiar to
|
|
meillo@133
|
3739 Unix users.
|
|
meillo@133
|
3740 .P
|
|
meillo@133
|
3741 MH allows users to have multiiple MH setups.
|
|
meillo@133
|
3742 Therefore, it is necessary to select a different profile.
|
|
meillo@133
|
3743 The profile is the single entry point to access the rest of a
|
|
meillo@133
|
3744 personal MH setup.
|
|
meillo@133
|
3745 In nmh, the environment variable
|
|
meillo@133
|
3746 .Ev MH
|
|
meillo@133
|
3747 could be used to specifiy a different profile.
|
|
meillo@133
|
3748 To operate in the same MH setup with a separate context,
|
|
meillo@133
|
3749 the
|
|
meillo@133
|
3750 .Ev MHCONTEXT
|
|
meillo@133
|
3751 environment variable could be used.
|
|
meillo@133
|
3752 This allows having own current folders and current messages in
|
|
meillo@133
|
3753 each terminal, for instance.
|
|
meillo@133
|
3754 In mmh, three environment variables are used.
|
|
meillo@133
|
3755 .Ev MMH
|
|
meillo@133
|
3756 overrides the default location of the mmh directory (\c
|
|
meillo@133
|
3757 .Fn .mmh ).
|
|
meillo@133
|
3758 .Ev MMHP
|
|
meillo@133
|
3759 and
|
|
meillo@133
|
3760 .Ev MMHC
|
|
meillo@133
|
3761 override the paths to the profile and context files, respectively.
|
|
meillo@133
|
3762 This approach allows the set of personal configuration files to be chosen
|
|
meillo@133
|
3763 independently from the profile, context, and mail storage.
|
|
meillo@133
|
3764 .P
|
|
meillo@133
|
3765 The separation of the files by type is sensible and convenient.
|
|
meillo@133
|
3766 The new approach has no functional disadvantages,
|
|
meillo@133
|
3767 as every setup I can imagine can be implemented with both approaches,
|
|
meillo@133
|
3768 possibly even easier with the new approach.
|
|
meillo@133
|
3769 The main achievement of the change is the clear and sensible split
|
|
meillo@133
|
3770 between mail storage and configuration.
|
|
meillo@133
|
3771
|
|
meillo@133
|
3772
|
|
meillo@133
|
3773
|
|
meillo@133
|
3774
|
|
meillo@133
|
3775
|
|
meillo@118
|
3776 .H2 "Modularization
|
|
meillo@118
|
3777 .P
|
|
meillo@123
|
3778 The source code of the mmh tools is located in the
|
|
meillo@122
|
3779 .Fn uip
|
|
meillo@123
|
3780 (``user interface programs'') directory.
|
|
meillo@123
|
3781 Each tools has a source file with the same name.
|
|
meillo@122
|
3782 For example,
|
|
meillo@122
|
3783 .Pn rmm
|
|
meillo@122
|
3784 is built from
|
|
meillo@122
|
3785 .Fn uip/rmm.c .
|
|
meillo@123
|
3786 Some source files are used for multiple programs.
|
|
meillo@122
|
3787 For example
|
|
meillo@122
|
3788 .Fn uip/scansbr.c
|
|
meillo@123
|
3789 is used for both,
|
|
meillo@122
|
3790 .Pn scan
|
|
meillo@122
|
3791 and
|
|
meillo@122
|
3792 .Pn inc .
|
|
meillo@122
|
3793 In nmh, 49 tools were built from 76 source files.
|
|
meillo@123
|
3794 This is a ratio of 1.6 source files per program.
|
|
meillo@123
|
3795 32 programs depended on multiple source files;
|
|
meillo@123
|
3796 17 programs depended on one source file only.
|
|
meillo@122
|
3797 In mmh, 39 tools are built from 51 source files.
|
|
meillo@123
|
3798 This is a ratio of 1.3 source files per program.
|
|
meillo@123
|
3799 18 programs depend on multiple source files;
|
|
meillo@123
|
3800 21 programs depend on one source file only.
|
|
meillo@123
|
3801 (These numbers and the ones in the following text ignore the MH library
|
|
meillo@123
|
3802 as well as shell scripts and multiple names for the same program.)
|
|
meillo@122
|
3803 .P
|
|
meillo@123
|
3804 Splitting the source code of a large program into multiple files can
|
|
meillo@122
|
3805 increase the readability of its source code.
|
|
meillo@124
|
3806 Most of the mmh tools, however, are simple and straight-forward programs.
|
|
meillo@122
|
3807 With the exception of the MIME handling tools,
|
|
meillo@122
|
3808 .Pn pick
|
|
meillo@122
|
3809 is the largest tools.
|
|
meillo@122
|
3810 It contains 1\|037 lines of source code (measured with
|
|
meillo@122
|
3811 .Pn sloccount ), excluding the MH library.
|
|
meillo@122
|
3812 Only the MIME handling tools (\c
|
|
meillo@122
|
3813 .Pn mhbuild ,
|
|
meillo@122
|
3814 .Pn mhstore ,
|
|
meillo@122
|
3815 .Pn show ,
|
|
meillo@122
|
3816 etc.)
|
|
meillo@122
|
3817 are larger.
|
|
meillo@122
|
3818 Splitting programs with less than 1\|000 lines of code into multiple
|
|
meillo@123
|
3819 source files seldom leads to better readability.
|
|
meillo@123
|
3820 For such tools, splitting makes sense
|
|
meillo@122
|
3821 when parts of the code are reused in other programs,
|
|
meillo@122
|
3822 and the reused code fragment is not general enough
|
|
meillo@122
|
3823 for including it in the MH library,
|
|
meillo@124
|
3824 or, if the code has dependencies on a library that only few programs need.
|
|
meillo@122
|
3825 .Fn uip/packsbr.c ,
|
|
meillo@122
|
3826 for instance, provides the core program logic for the
|
|
meillo@122
|
3827 .Pn packf
|
|
meillo@122
|
3828 and
|
|
meillo@122
|
3829 .Pn rcvpack
|
|
meillo@122
|
3830 programs.
|
|
meillo@122
|
3831 .Fn uip/packf.c
|
|
meillo@122
|
3832 and
|
|
meillo@122
|
3833 .Fn uip/rcvpack.c
|
|
meillo@122
|
3834 mainly wrap the core function appropriately.
|
|
meillo@122
|
3835 No other tools use the folder packing functions.
|
|
meillo@123
|
3836 As another example,
|
|
meillo@123
|
3837 .Fn uip/termsbr.c
|
|
meillo@123
|
3838 provides termcap support, which requires linking with a termcap or
|
|
meillo@123
|
3839 curses library.
|
|
meillo@123
|
3840 Including
|
|
meillo@123
|
3841 .Fn uip/termsbr.c
|
|
meillo@123
|
3842 into the MH library would require every program to be linked with
|
|
meillo@123
|
3843 termcap or curses, although only few of the programs require it.
|
|
meillo@122
|
3844 .P
|
|
meillo@122
|
3845 The task of MIME handling is complex enough that splitting its code
|
|
meillo@122
|
3846 into multiple source files improves the readability.
|
|
meillo@122
|
3847 The program
|
|
meillo@122
|
3848 .Pn mhstore ,
|
|
meillo@122
|
3849 for instance, is compiled out of seven source files with 2\|500
|
|
meillo@122
|
3850 lines of code in summary.
|
|
meillo@122
|
3851 The main code file
|
|
meillo@122
|
3852 .Fn uip/mhstore.c
|
|
meillo@123
|
3853 consists of 800 lines; the other 1\|700 lines of code are reused in
|
|
meillo@123
|
3854 other MIME handling tools.
|
|
meillo@123
|
3855 It seems to be worthwhile to bundle the generic MIME handling code into
|
|
meillo@123
|
3856 a MH-MIME library, as a companion to the MH standard library.
|
|
meillo@122
|
3857 This is left open for the future.
|
|
meillo@122
|
3858 .P
|
|
meillo@123
|
3859 The work already done, focussed on the non-MIME tools.
|
|
meillo@122
|
3860 The amount of code compiled into each program was reduced.
|
|
meillo@123
|
3861 This eases the understanding of the code base.
|
|
meillo@122
|
3862 In nmh,
|
|
meillo@122
|
3863 .Pn comp
|
|
meillo@122
|
3864 was built from six source files:
|
|
meillo@122
|
3865 .Fn comp.c ,
|
|
meillo@122
|
3866 .Fn whatnowproc.c ,
|
|
meillo@122
|
3867 .Fn whatnowsbr.c ,
|
|
meillo@122
|
3868 .Fn sendsbr.c ,
|
|
meillo@122
|
3869 .Fn annosbr.c ,
|
|
meillo@122
|
3870 and
|
|
meillo@122
|
3871 .Fn distsbr.c .
|
|
meillo@122
|
3872 In mmh, it builds from only two:
|
|
meillo@122
|
3873 .Fn comp.c
|
|
meillo@122
|
3874 and
|
|
meillo@122
|
3875 .Fn whatnowproc.c .
|
|
meillo@123
|
3876 In nmh's
|
|
meillo@123
|
3877 .Pn comp ,
|
|
meillo@123
|
3878 the core function of
|
|
meillo@122
|
3879 .Pn whatnow ,
|
|
meillo@122
|
3880 .Pn send ,
|
|
meillo@122
|
3881 and
|
|
meillo@122
|
3882 .Pn anno
|
|
meillo@123
|
3883 were compiled into
|
|
meillo@122
|
3884 .Pn comp .
|
|
meillo@123
|
3885 This saved the need to execute these programs with
|
|
meillo@122
|
3886 .Fu fork()
|
|
meillo@122
|
3887 and
|
|
meillo@122
|
3888 .Fu exec() ,
|
|
meillo@122
|
3889 two expensive system calls.
|
|
meillo@122
|
3890 Whereis this approach improved the time performance,
|
|
meillo@122
|
3891 it interweaved the source code.
|
|
meillo@122
|
3892 Core functionalities were not encapsulated into programs but into
|
|
meillo@122
|
3893 function, which were then wrapped by programs.
|
|
meillo@122
|
3894 For example,
|
|
meillo@122
|
3895 .Fn uip/annosbr.c
|
|
meillo@122
|
3896 included the function
|
|
meillo@122
|
3897 .Fu annotate() .
|
|
meillo@122
|
3898 Each program that wanted to annotate messages, included the source file
|
|
meillo@123
|
3899 .Fn uip/annosbr.c
|
|
meillo@123
|
3900 and called
|
|
meillo@123
|
3901 .Fu annotate() .
|
|
meillo@123
|
3902 Because the function
|
|
meillo@123
|
3903 .Fu annotate()
|
|
meillo@123
|
3904 was used like the tool
|
|
meillo@123
|
3905 .Pn anno ,
|
|
meillo@123
|
3906 it had seven parameters, reflecting the command line switches of the tool.
|
|
meillo@122
|
3907 When another pair of command line switches was added to
|
|
meillo@122
|
3908 .Pn anno ,
|
|
meillo@122
|
3909 a rather ugly hack was implemented to avoid adding another parameter
|
|
meillo@122
|
3910 to the function.
|
|
meillo@122
|
3911 .Ci d9b1d57351d104d7ec1a5621f090657dcce8cb7f
|
|
meillo@122
|
3912 .P
|
|
meillo@122
|
3913 Separation simplifies the understanding of program code
|
|
meillo@122
|
3914 because the area influenced by any particular statement is smaller.
|
|
meillo@122
|
3915 The separating on the program-level is more strict than the separation
|
|
meillo@122
|
3916 on the function level.
|
|
meillo@122
|
3917 In mmh, the relevant code of
|
|
meillo@122
|
3918 .Pn comp
|
|
meillo@122
|
3919 comprises the two files
|
|
meillo@122
|
3920 .Fn uip/comp.c
|
|
meillo@122
|
3921 and
|
|
meillo@122
|
3922 .Fn uip/whatnowproc.c ,
|
|
meillo@123
|
3923 together 210 lines of code.
|
|
meillo@122
|
3924 In nmh,
|
|
meillo@122
|
3925 .Pn comp
|
|
meillo@122
|
3926 comprises six files with 2\|450 lines.
|
|
meillo@123
|
3927 Not all of the code in these six files was actually used by
|
|
meillo@122
|
3928 .Pn comp ,
|
|
meillo@123
|
3929 but the code reader needed to read all of the code first to know which
|
|
meillo@123
|
3930 parts were used.
|
|
meillo@122
|
3931 .P
|
|
meillo@123
|
3932 As I have read a lot in the code base during the last two years,
|
|
meillo@123
|
3933 I learned about the easy and the difficult parts.
|
|
meillo@123
|
3934 Code is easy to understand if:
|
|
meillo@123
|
3935 .BU
|
|
meillo@139
|
3936 The influenced code area is small.
|
|
meillo@123
|
3937 .BU
|
|
meillo@139
|
3938 The boundaries are strictly defined.
|
|
meillo@123
|
3939 .BU
|
|
meillo@139
|
3940 The code is written straight-forward.
|
|
meillo@123
|
3941 .P
|
|
meillo@123
|
3942 .\" XXX move this paragraph somewhere else?
|
|
meillo@123
|
3943 Reading
|
|
meillo@122
|
3944 .Pn rmm 's
|
|
meillo@122
|
3945 source code in
|
|
meillo@122
|
3946 .Fn uip/rmm.c
|
|
meillo@122
|
3947 is my recommendation for a beginner's entry point into the code base of nmh.
|
|
meillo@122
|
3948 The reasons are that the task of
|
|
meillo@122
|
3949 .Pn rmm
|
|
meillo@122
|
3950 is straight forward and it consists of one small source code file only,
|
|
meillo@122
|
3951 yet its source includes code constructs typical for MH tools.
|
|
meillo@122
|
3952 With the introduction of the trash folder in mmh,
|
|
meillo@122
|
3953 .Pn rmm
|
|
meillo@122
|
3954 became a bit more complex, because it invokes
|
|
meillo@122
|
3955 .Pn refile .
|
|
meillo@122
|
3956 Still, it is a good example for a simple tool with clear sources.
|
|
meillo@122
|
3957 .P
|
|
meillo@122
|
3958 Understanding
|
|
meillo@122
|
3959 .Pn comp
|
|
meillo@122
|
3960 requires to read 210 lines of code in mmh, but ten times as much in nmh.
|
|
meillo@123
|
3961 Due to the aforementioned hack in
|
|
meillo@122
|
3962 .Pn anno
|
|
meillo@122
|
3963 to save the additional parameter, information passed through the program's
|
|
meillo@122
|
3964 source base in obscure ways.
|
|
meillo@123
|
3965 Thus, understanding
|
|
meillo@122
|
3966 .Pn comp ,
|
|
meillo@123
|
3967 required understanding the inner workings of
|
|
meillo@122
|
3968 .Fn uip/annosbr.c
|
|
meillo@122
|
3969 first.
|
|
meillo@123
|
3970 To be sure to fully understand a program, its whole source code needs
|
|
meillo@122
|
3971 to be examined.
|
|
meillo@123
|
3972 Not doing so is a leap of faith, assuming that the developers
|
|
meillo@122
|
3973 have avoided obscure programming techniques.
|
|
meillo@122
|
3974 By separating the tools on the program-level, the boundaries are
|
|
meillo@122
|
3975 clearly visible and technically enforced.
|
|
meillo@122
|
3976 The interfaces are calls to
|
|
meillo@122
|
3977 .Fu exec()
|
|
meillo@122
|
3978 rather than arbitrary function calls.
|
|
meillo@123
|
3979 .P
|
|
meillo@123
|
3980 But the real problem is another:
|
|
meillo@123
|
3981 Nmh violates the golden ``one tool, one job'' rule of the Unix philosophy.
|
|
meillo@123
|
3982 Understanding
|
|
meillo@122
|
3983 .Pn comp
|
|
meillo@123
|
3984 requires understanding
|
|
meillo@123
|
3985 .Fn uip/annosbr.c
|
|
meillo@123
|
3986 and
|
|
meillo@123
|
3987 .Fn uip/sendsbr.c
|
|
meillo@123
|
3988 because
|
|
meillo@123
|
3989 .Pn comp
|
|
meillo@123
|
3990 does annotate and send messages.
|
|
meillo@123
|
3991 In nmh, there surely exists the tool
|
|
meillo@122
|
3992 .Pn send ,
|
|
meillo@123
|
3993 which does (almost) only send messages.
|
|
meillo@123
|
3994 But
|
|
meillo@122
|
3995 .Pn comp
|
|
meillo@123
|
3996 and
|
|
meillo@122
|
3997 .Pn repl
|
|
meillo@122
|
3998 and
|
|
meillo@122
|
3999 .Pn forw
|
|
meillo@122
|
4000 and
|
|
meillo@122
|
4001 .Pn dist
|
|
meillo@122
|
4002 and
|
|
meillo@122
|
4003 .Pn whatnow
|
|
meillo@122
|
4004 and
|
|
meillo@123
|
4005 .Pn viamail ,
|
|
meillo@123
|
4006 they all (!) have the same message sending function included, too.
|
|
meillo@123
|
4007 In result,
|
|
meillo@123
|
4008 .Pn comp
|
|
meillo@123
|
4009 sends messages without using
|
|
meillo@123
|
4010 .Pn send .
|
|
meillo@123
|
4011 The situation is the same as if
|
|
meillo@123
|
4012 .Pn grep
|
|
meillo@123
|
4013 would page without
|
|
meillo@123
|
4014 .Pn more
|
|
meillo@123
|
4015 just because both programs are part of the same code base.
|
|
meillo@123
|
4016 .P
|
|
meillo@122
|
4017 The clear separation on the surface \(en the toolchest approach \(en
|
|
meillo@123
|
4018 is violated on the level below.
|
|
meillo@122
|
4019 This violation is for the sake of time performance.
|
|
meillo@122
|
4020 On systems where
|
|
meillo@122
|
4021 .Fu fork()
|
|
meillo@122
|
4022 and
|
|
meillo@122
|
4023 .Fu exec()
|
|
meillo@122
|
4024 are expensive, the quicker response might be noticable.
|
|
meillo@124
|
4025 In the old times, sacrificing readability and conceptional beauty for
|
|
meillo@124
|
4026 speed might even have been a must to prevent MH from being unusably slow.
|
|
meillo@122
|
4027 Whatever the reasons had been, today they are gone.
|
|
meillo@123
|
4028 No longer should we sacrifice readability or conceptional beauty.
|
|
meillo@122
|
4029 No longer should we violate the Unix philosophy's ``one tool, one job''
|
|
meillo@122
|
4030 guideline.
|
|
meillo@123
|
4031 No longer should we keep speed improvements that became unnecessary.
|
|
meillo@122
|
4032 .P
|
|
meillo@123
|
4033 Therefore, mmh's
|
|
meillo@123
|
4034 .Pn comp
|
|
meillo@123
|
4035 does no longer send messages.
|
|
meillo@123
|
4036 In mmh, different jobs are divided among separate programs that
|
|
meillo@122
|
4037 invoke each other as needed.
|
|
meillo@123
|
4038 In consequence,
|
|
meillo@123
|
4039 .Pn comp
|
|
meillo@123
|
4040 invokes
|
|
meillo@123
|
4041 .Pn whatnow
|
|
meillo@123
|
4042 which thereafter invokes
|
|
meillo@123
|
4043 .Pn send .
|
|
meillo@123
|
4044 The clear separation on the surface is maintained on the level below.
|
|
meillo@123
|
4045 Human users and the tools use the same interface \(en
|
|
meillo@123
|
4046 annotations, for example, are made by invoking
|
|
meillo@123
|
4047 .Pn anno ,
|
|
meillo@123
|
4048 no matter if requested by programs or by human beings.
|
|
meillo@123
|
4049 The decrease of tools built from multiple source files and thus
|
|
meillo@123
|
4050 the decrease of
|
|
meillo@123
|
4051 .Fn uip/*sbr.c
|
|
meillo@123
|
4052 files confirm the improvement.
|
|
meillo@123
|
4053 .P
|
|
meillo@145
|
4054 .\" XXX move this paragraph up somewhere
|
|
meillo@123
|
4055 One disadvantage needs to be taken with this change:
|
|
meillo@123
|
4056 The compiler can no longer check the integrity of the interfaces.
|
|
meillo@123
|
4057 By changing the command line interfaces of tools, it is
|
|
meillo@123
|
4058 the developer's job to adjust the invocations of these tools as well.
|
|
meillo@123
|
4059 As this is a manual task and regression tests, which could detect such
|
|
meillo@124
|
4060 problems, are not available yet, it is prone to errors.
|
|
meillo@123
|
4061 These errors will not be detected at compile time but at run time.
|
|
meillo@123
|
4062 Installing regression tests is a task left to do.
|
|
meillo@123
|
4063 In the best case, a uniform way of invoking tools from other tools
|
|
meillo@123
|
4064 can be developed to allow automated testing at compile time.
|
|
meillo@145
|
4065
|
|
meillo@145
|
4066
|
|
meillo@145
|
4067 .ig
|
|
meillo@145
|
4068 XXX consider writing about mhl vs. mhlproc
|
|
meillo@145
|
4069
|
|
meillo@145
|
4070 sbr/showfile.c
|
|
meillo@145
|
4071
|
|
meillo@145
|
4072 23 /*
|
|
meillo@145
|
4073 24 ** If you have your lproc listed as "mhl",
|
|
meillo@145
|
4074 25 ** then really invoked the mhlproc instead
|
|
meillo@145
|
4075 26 ** (which is usually mhl anyway).
|
|
meillo@145
|
4076 27 */
|
|
meillo@145
|
4077
|
|
meillo@145
|
4078 Sat Nov 24 19:09:14 1984 /mtr (agent: Marshall Rose) <uci@udel-dewey>
|
|
meillo@145
|
4079
|
|
meillo@145
|
4080 sbr/showfile.c: if lproc is "mhl", use mhlproc for consistency
|
|
meillo@145
|
4081 (Actually, user should use "lproc: show", "showproc: mhl".)
|
|
meillo@145
|
4082 ..
|
