# HG changeset patch
# User markus schnalke <meillo@marmaro.de>
# Date 1335283328 -7200
# Node ID ab5253e48c7483ca17f5fc937488d8decccb751f
# Parent  db3567c9cc3f6e053306dc8e9918e5f4646e7c1b
Wrote about the directory split.
style: New macro for env vars.

diff -r db3567c9cc3f -r ab5253e48c74 ch03.roff
--- a/ch03.roff	Tue Apr 24 16:52:25 2012 +0200
+++ b/ch03.roff	Tue Apr 24 18:02:08 2012 +0200
@@ -291,8 +291,94 @@
 
 .H1 "MH Directory Split
 .P
-Historically, a personal MH setup had consisted of two things:
-the 
+In MH and nmh, a personal setup had consisted of two parts:
+The MH profile, named
+.Fn \&.mh_profile
+and being located directly in the user's home directory.
+And the MH directory, where all his mail messages and also his personal
+forms, scan formats, other configuration files are stored. The location
+of this directory could be user-chosen. The default was to name it
+.Fn Mail
+and have it directly in the home directory.
+.P
+I've never liked the data storage and the configuration to be intermixed.
+They are different kinds of data. One part, are the messages,
+which are the data to operate on. The other part, are the personal
+configuration files, which are able to change the behavior of the operations.
+The actual operations are defined in the profile, however.
+.P
+When storing data, one should try to group data by its type.
+There's sense in the Unix file system hierarchy, where configuration
+file are stored separate (\c
+.Fn /etc )
+to the programs (\c
+.Fn /bin
+and
+.Fn /usr/bin )
+to their sources (\c
+.Fn /usr/src ).
+Such separation eases the backup management, for instance.
+.P
+In mmh, I've reorganized the file locations.
+Still there are two places:
+There's the mail storage directory, which, like in MH, contains all the
+messages, but, unlike in MH, nothing else.
+Its location still is user-chosen, with the default name
+.Fn Mail ,
+in the user's home directory. This is much similar to the case in nmh.
+The configuration files, however, are grouped together in the new directory
+.Fn \&.mmh
+in the user's home directory.
+The user's profile now is a file, named
+.Fn profile ,
+in this mmh directory.
+Consistently, the context file and all the personal forms, scan formats,
+and the like, are also there.
+.P
+The naming changed with the relocation.
+The directory where everything, except the profile, had been stored (\c
+.Fn $HOME/Mail ),
+used to be called \fIMH directory\fP. Now, this directory is called the
+user's \fImail storage\fP. The name \fImmh directory\fP is now given to
+the new directory
+(\c
+.Fn $HOME/.mmh ),
+containing all the personal configuration files.
+.P
+The separation of the files by type of content is logical and convenient.
+There are no functional differences as any possible setup known to me
+can be implemented with both approaches, although likely a bit easier
+with the new approach. The main goal of the change had been to provide
+sensible storage locations for any type of personal mmh file.
+.P
+In order for one user to have multiple MH setups, he can use the
+environment variable
+.Ev MH
+the point to a different profile file.
+The MH directory (mail storage plus personal configuration files) is
+defined by the
+.Pe Path
+profile entry.
+The context file could be defined by the
+.Pe context
+profile entry or by the
+.Ev MHCONTEXT
+environment variable.
+The latter is useful to have a distinct context (e.g. current folders)
+in each terminal window, for instance.
+In mmh, there are three environment variables now.
+.Ev MMH
+may be used to change the location of the mmh directory.
+.Ev MMHP
+and
+.Ev MMHC
+change the profile and context files, respectively.
+Besides providing a more consistent feel (which simply is the result
+of being designed anew), the set of personal configuration files can
+be chosen independently from the profile (including mail storage location)
+and context, now. Being it relevant for practical use or not, it
+de-facto is an improvement. However, the main achievement is the
+split between mail storage and personal configuration files.
 
 
 .H1 "Path Notations
diff -r db3567c9cc3f -r ab5253e48c74 style
--- a/style	Tue Apr 24 16:52:25 2012 +0200
+++ b/style	Tue Apr 24 18:02:08 2012 +0200
@@ -231,6 +231,9 @@
 .de Fu  \" function
 .CW "\\$1" "\\$2
 ..
+.de Ev  \" env variable
+.CW "\\$1" "\\$2
+..
 .de Cl  \" command line
 `\c
 .CW "\\$1" "'\\$2