.H0 "Work Report
.P
foo
.P
bar

.H1 "Removal of Code Relicts
.P
The code base of mmh originates in the late 70s, had been extensively
worked on in the mid 80s, and had been partly reorganized and extended
in the 90s. Relicts of all those times had gathered in the code base.
My goal was to remove any ancient code parts. One part of the task was
converting obsolete code constructs to standard constructs, the other part
was dropping obsolete functions.
.P
As I'm not even thirty years old and have no more than seven years of
Unix experience, I needed to learn about the history in retroperspective.
Older people likely have used those ancient constructs themself
and have suffered from their incompatiblities and have longed for
standardization. Unfortunately, I have only read that others had done so.
This put me in a much more difficult positions when working on the old
code. I needed to recherche what other would have known by heart from
experience. All my programming experience comes from a time past ANSI C
and past POSIX. Although I knew about the times before, I took the
current state implicitely for granted most of the time.
.P
Being aware of
these facts, I rather let people with more historic experience solve the 
task of converting the ancient code constructs to standardized ones.
Luckily, Lyndon Nerenberg focused on this task at the nmh project.
He converted large parts of the code to POSIX constructs, removing
the conditionals compilation for now standardized features.
I'm thankful for this task being solved. I only pulled the changes into
mmh.
.P
The other task of dropping ancient functionality to remove old code,
I did myself, though. My position to strip mmh to the bare minimum of
frequently used features is much more revolutional than the nmh community
sees it. Without the need to justify my decisions, I was able to quickly
remove code I considered ancient. The need to discuss my decisions with
peers likely would have slowed this process down. Of course, I did research
if a particular feature really should be dropped. Having not had any
contact to this feature within my computer life was a first indicator to
drop it, but I also asked others and searched the literature for modern
usage of the feature. If it appeared to be truly ancient, I dropped it.
The reason for dropping is always part of the commit message in the
version control system. Thus, it is easy for others to check their
view on the topic with mine and possibly to argue for reinclusion.

.U2 "MMDF maildrop support
.P
I did drop any support for the MMDF maildrop format. This type of format
is conceptionally similar to the mbox format, but uses four bytes with
value 1 (\fL^A^A^A^A\fP) as message delimiter,
instead of the string ``\fLFrom\0\fP''.
Due to the similarity and mbox being the de-facto standard maildrop
format on Unix, but also due to the larger influence of Sendmail than MMDF,
the MMDF maildrop format had vanished.
.P
The simplifications within the code were only moderate. Switches could
be removed from tools like
.L packf ,
which generate packed mailboxes. Only one packed mailbox format remained:
mbox.
The most important changes affect the equally named mail parsing routine in
.L sbr/m_getfld.c .
The direct MMDF code had been removed, but as now only one packed mailbox
format is left, code structure simplifications are likely possible.
The reason why they are still outstanding is the heavily optimized code
of \fLm_getfld()\fP. Changes beyond a small local scope \(en
which restructuring in its core is \(en cause a high risk of damaging
the intricate workings of the optimized code. This problem is know
to the developers of nmh, too. They also avoid touching this minefield
if possible.

.U2 "UUCP Bang Paths
.P
More questionably than the former topic is the removal of support for the
UUCP bang path address style. However, the user may translate the bang
paths on retrieval to Internet addresses and the other way on posting
messages. The former can be done my an MDA like procmail; the latter
by a sendmail wrapper. This would ensure that any address handling would
work as expected. However, it might just work well without any
such modifications, as mmh does not touch addresses much, in general.
But I can't ensure as I have never used an environment with bang paths.
Also, the behavior might break at any point in further development.

.U2 "Hardcopy terminal support
.P
More of a funny anecdote is the remaining of a check for printing to a
hardcopy terminal until Spring 2012, when I finally removed it.
I surely would be very happy to see such a terminal in action, maybe
actually being able to work on it, but I fear my chances are null.
.P
The check only prevented a pager to be placed between the outputting
program (\fLmhl\fP) and the terminal. This could have been ensured with
the \fL-nomoreproc\fP at the command line statically, too.

.U2 "Removed support for header fields
.P
The `Encrypted' header had been introduced by RFC\^822, but already
marked legacy in RFC 2822. It was superseded by FIXME.
Mmh does no more support this header.
.P
`Content-MD5' headers were introduced by RFC\^1864. They provide only
a verification of data corruption during the transfer. By no means can
they ensure verbatim end-to-end delivery of the contents. This is clearly
stated in the RFC. The proper approach to provide verificationability
of content in an end-to-end relationship is the use of digital cryptography
(RFCs FIXME). On the other hand, transfer protocols should ensure the
integrity of the transmission. In combinations these two approaches
make the `Content-MD5' header field useless. In consequence, I removed
the support for it. By this removal, MD5 computation is not needed
anywhere in mmh. Hence, over 500 lines of code were removed by this one
change. Even if the `Content-MD5' header field is useful sometimes,
I value its usefulnes less than the improvement in maintainability, caused
by the removal.


.H1 "Draft and Trash Folders
.U2 "Draft Folder
.P
Historically, MH provided exactly one draft message, named `\fLdraft\fP' and
being located in the MH directory. When starting to compose another message
before the former one was sent, the user had been questioned wether to use,
refile or replace the old draft. Working on multiple drafts at the same time
was impossible. One could only work on them in alteration by refiling the
previous one to some directory and fetching some other one for reediting. 
This manual draft management needed to be done each time the user wanted
to switch between editing one draft to editing another.
.P
To allow true parallel editing of drafts, in a straight forward way, the
draft folder facility exists. It had been introduced already in July 1984
by Marshall T. Rose. The facility was deactivated by default.
Even in nmh, the draft folder facility remained deactivated by default.
At least, Richard Coleman added the man page \fImh-draft(5)\fP to document
the feature well.
.P
The only advantage of not using the draft folder facility is the static
name of the draft file. This could be an issue for MH frontends like mh-e.
But as they likely want to provide working on multiple drafts in parallel,
the issue is only concerning compatibility. The aim of nmh to stay compatible
prevented the default activation of the draft folder facility.
.P
On the other hand, a draft folder is the much more natural concept than
a draft message. MH's mail storage consists of folders and messages,
the messages named with ascending numbers. A draft message breaks with this
concept by introducing a message in a file named ``\fLdraft\fP''. This draft
message is special. It can not be simply listed with the available tools,
but instead requires special switches. I.e. corner-cases were
introduced. A draft folder, in contrast, does not introduce such
corner-cases. The available tools can operate on the messages within that
folder like on any messages within any mail folders. The only difference
is the fact that the default folder for \fLsend\fP is the draft folder,
instead of the current folder, like for all other tools.
.P
The trivial part of the change was activating the draft folder facility
by default and setting a default name for this folder. Obviously, I chose
the name ``\fL+drafts\fP''. This made the \fL\-draftfolder\fP and
\fL\-draftmessage\fP switches useless, and I could remove them.
The more difficult but also the part that showed the real improvement,
was updating the tools to the new concept. \fL\-draft\fP switches could
be dropped, as operating on a draft message became indistinguishable to
operating on any other message for the tools. \fLcomp\fP still has its
\fL\-use\fP switch for switching between its two modes: (1) Compose a new
draft, possibly by taking some existing message as a form. (2) Modify
an existing draft. In either case, the behavior of \fLcomp\fP is
deterministic. There is no more need to query the user. I consider this
a major improvement. By making \fLsend\fP simply operate on the current
message in the draft folder by default, with message and folder both
overridable by specifying them on the command line, it is now possible
to send a draft anywhere within the storage by simply specifying its folder
and name.
.P
All theses changes converted special cases to regular cases, thus
simplifying the tools and increasing the flexibility.

.U2 "Trash Folder
.P
Similar to the situation for drafts is the situation for removed messages.
Historically, a message was deleted by renaming. A specific
\fIbackup prefix\fP, often comma (\fL,\fP) or hash (\fL#\fP),
being prepended to the file name. Thus, MH wouldn't recognize the file
as a message anymore, as only files whose name consists of digits only
are treated as messages. The removed messages remained as files in the
same directory and needed some maintenance job to truly delete them after
some grace time. Usually, by running a command similar to
.DS
find /home/user/Mail \-ctime +7 \-name ',*' | xargs rm
.DE
in a cron job. Within the grace time interval
the original message could be restored by stripping the
the backup prefix from the file name. If however, the last message of
a folder is been removed \(en say message `\fL6\fP' becomes file
`\fL,6\fP' \(en and a new message enters the same folder, thus the same
numbered being given again \(en in our case `\fL6\fP' \(en, if that one
is removed too, then the backup of the former message gets overwritten.
Thus, the ability to restore removed messages does not only depend on
the ``sweeping cron job'' but also on the removing of further messages.
This is undesireable, because the real mechanism is hidden from the user
and the concequences of further removals are not always obvious.
Further more, the backup files are scattered within the whole mail
storage, instead of being collected at one place.
.P
To improve the situation, the profile entry \fIrmmproc\fP
(previously named \fIDelete-Prog\fP) was introduced, very early.
It could be set to any command, which would care for the mail removal
instead of taking the default action, described above.
Refiling the to-be-removed files to some wastebin folder was a common
example. Nmh's man page for \fLrmm(1)\fP proposes `\fLrefile +d\fP'
to move messages to the wastebin and `\fLrm `mhpath +d all`\fP'
the empty the wastebin.
Managing the message removal this way is a sane approach. It keeps
the removed messages in one place, makes it easy to remove the backup
files, and, most important, enables the user to use the tools of MH
itself to operate on the removed messages. One can \fLscan\fP them,
\fLshow\fP them, and restore them with \fLrefile(1)\fP. There's no more
need to use \fLmhpath\fP to switch over from MH tools to Unix tools
\(en MH can do it all itself.
.P
This apporach is matches perfect with the concepts of MH, thus making
it powerful. Hence, I made it the default. And even more, I also
removed the old backup prefix approach, as it is clearly less powerful.
Keeping unused alternative in the code is a bad choice as they likely
gather bugs, by not being constantly tested. Also, the increased code
size and more conditions crease the maintenance costs. By strictly
converting to the trash folder approach, I simplified the code base.
\fLrmm(1)\fP calls \fLrefile(1)\fP internally to move the to-be-removed
message to the trash folder (`\fL+trash\fP' by default). Messages
there can be operated on like on any other message in the storage.
The sweep clean, one can use `\fLrmm \-unlink +trash a\fP', where
the `\fL\-unlink\fP' switch causes the files to be truly unliked instead
of moved to the trash folder.


.H1 "MH Directory Split
.P



.H1 "Path Notations
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foo

.H1 "Attachments
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foo

.H1 "Blind Carbon Copies
.P
foo

.H1 "Good Defaults
.P
foo

.H1 "Modularization
.P
foo

.H1 "Code style
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foo