[mmh] / man / mh-sequence.man7

.\"
.\" %nmhwarning%
.\"
.TH MH-SEQUENCE %manext7% "%nmhdate%" MH.6.8 [%nmhversion%]
.SH NAME
mh-sequence \- sequence specification for nmh message system
.SH SYNOPSIS
most
.B nmh
commands
.SH DESCRIPTION
A sequence (or sequence set) is a symbolic name representing a
message or collection of messages.
.B nmh
has several internally
defined sequences, as well as allowing users to define their own
sequences.

.SS "Message Specification and Pre\-Defined Message Sequences"
Most
.B nmh
commands accept a `msg' or `msgs' specification, where
`msg' indicates one message and `msgs' indicates one or more messages.
To designate a message, you may use either its number (e.g., 1, 10, 234)
or one of these \*(lqreserved\*(rq message names:
.PP
.RS 5
.nf
.ta +\w'\fIName\fP      'u
.I Name Description
first   the first message in the folder
last    the last message in the folder
cur     the most recently accessed message
prev    the message numerically preceding \*(lqcur\*(rq
next    the message numerically following \*(lqcur\*(rq
.fi
.RE
.PP
In commands that take a `msg' argument, the default is \*(lqcur\*(rq.
As a shorthand, \*(lq\&.\*(rq is equivalent to \*(lqcur\*(rq.
.PP
For example: In a folder containing five messages numbered 5, 10, 94, 177
and 325, \*(lqfirst\*(rq is 5 and \*(lqlast\*(rq is 325.  If \*(lqcur\*(rq
is 94, then \*(lqprev\*(rq is 10 and \*(lqnext\*(rq is 177.
.PP
The word `msgs' indicates that one or more messages may be specified.
Such a specification consists of one message designation or of several
message designations separated by spaces.  A message designation consists
either of a message name as defined above, or a message range.
.PP
A message range is specified as \*(lqname1\-name2\*(rq or
\*(lqname:n\*(rq, where `name', `name1' and `name2' are message names,
and `n' is an integer.
.PP
The specification \*(lqname1\-name2\*(rq designates all currently existing
messages from `name1' to `name2' inclusive.  The \*(lqreserved\*(rq
message name \*(lqall\*(rq is a shorthand for the message range
\*(lqfirst\-last\*(rq.
.PP
The specification \*(lqname:n\*(rq designates up to `n' messages.
These messages start with `name' if `name' is a message number or one of
the reserved names \*(lqfirst\*(rq \*(lqcur\*(rq, or \*(lqnext\*(rq, The
messages end with `name' if `name' is \*(lqprev\*(rq or \*(lqlast\*(rq.
The interpretation of `n' may be overridden by preceding `n' with a
plus or minus sign; `+n' always means up to `n' messages starting with
`name', and `\-n' always means up to `n' messages ending with `name'.
.PP
In commands which accept a `msgs' argument, the default is either
\*(lqcur\*(rq or \*(lqall\*(rq, depending on which makes more sense
for each command (see the individual man pages for details).  Repeated
specifications of the same message have the same effect as a single
specification of the message.
.PP
There is also a special \*(lqreserved\*(rq message name \*(lqnew\*(rq
which is used by the
.B mhpath
command.

.SS "User\-Defined Message Sequences"
In addition to the \*(lqreserved\*(rq (pre-defined) message names given
above,
.B nmh
supports user-defined sequence names.  User-defined
sequences allow the
.B nmh
user a tremendous amount of power in dealing
with groups of messages in the same folder by allowing the user to bind
a group of messages to a meaningful symbolic name.
.PP
The name used to denote a message sequence must consist of an alphabetic
character followed by zero or more alphanumeric characters, and can not
be one of the \*(lqreserved\*(rq message names above.  After defining a
sequence, it can be used wherever an
.B nmh
command expects a `msg' or
`msgs' argument.
.PP
Some forms of message ranges are allowed with user-defined sequences.
The specification \*(lqname:n\*(rq may be used, and it designates up
to the first `n' messages (or last `n' messages for `\-n') which are
elements of the user-defined sequence `name'.
.PP
The specifications \*(lqname:next\*(rq and \*(lqname:prev\*(rq may also
be used, and they designate the next or previous message (relative to the
current message) which is an element of the user-defined sequence `name'.
The specifications \*(lqname:first\*(rq and \*(lqname:last\*(rq are
equivalent to \*(lqname:1\*(rq and \*(lqname:\-1\*(rq, respectively.  The
specification \*(lqname:cur\*(rq is not allowed (use just \*(lqcur\*(rq
instead).  The syntax of these message range specifications is subject
to change in the future.
.PP
User-defined sequence names are specific to each folder.  They are
defined using the
.B pick
and
.B mark
commands.
.PP
.SS "Public and Private User-Defined Sequences"
There are two varieties of user-defined sequences:
public and private.  Public sequences of a folder are accessible to any
.B nmh
user that can read that folder.  They are kept in each folder
in the file determined by the \*(lqMh\-Sequences\*(rq profile entry
(default is
.IR \&.mh_sequences ).
Private sequences are accessible
only to the
.B nmh
user that defined those sequences and are kept in
the user's
.B nmh
context file.
.PP
In general, the commands that create sequences (such as
.B pick
and
.BR mark )
will create public sequences if the folder for which
the sequences are being defined is writable by the
.B nmh
user.
For most commands, this can be overridden by using the switches
.B \-public
and
.BR \-private .
But if the folder is read\-only, or if
the \*(lqMh\-Sequences\*(rq profile entry is defined but empty, then
\fIprivate\fR sequences will be created instead.

.SS "Sequence Negation"
.B Nmh
provides the ability to select all messages not elements of a
user-defined sequence.  To do this, the user should define the entry
\*(lqSequence\-Negation\*(rq in the
.B nmh
profile file; its value
may be any string.  This string is then used to preface an existing
user-defined sequence name.  This specification then refers to those
messages not elements of the specified sequence name.  For example, if
the profile entry is:
.PP
.RS 5
Sequence\-Negation: not
.RE
.PP
then anytime an
.B nmh
command is given \*(lqnotfoo\*(rq as a `msg' or
`msgs' argument, it would substitute all messages that are not elements
of the sequence \*(lqfoo\*(rq.
.PP
Obviously, the user should beware of defining sequences with names that
begin with the value of the \*(lqSequence\-Negation\*(rq profile entry.

.SS "The Previous Sequence"
.B Nmh
provides the ability to remember the `msgs' or `msg' argument
last given to an
.B nmh
command.  The entry \*(lqPrevious\-Sequence\*(rq
should be defined in the
.B nmh
profile; its value should be a sequence
name or multiple sequence names separated by spaces.  If this entry
is defined, when an
.B nmh
command finishes, it will define the
sequence(s) named in the value of this entry to be those messages that
were specified to the command.  Hence, a profile entry of
.PP
.RS 5
Previous\-Sequence: pseq
.RE
.PP
directs any
.B nmh
command that accepts a `msg' or `msgs' argument to
define the sequence \*(lqpseq\*(rq as those messages when it finishes.
.PP
.BR Note :
there can be a performance penalty in using the
\*(lqPrevious\-Sequence\*(rq facility.  If it is used,
.B all
.B nmh
programs have to write the sequence information to the
.I \&.mh_sequences
file for the folder each time they run.  If the
\*(lqPrevious\-Sequence\*(rq profile entry is not included, only
.B pick
and
.B mark
will write to the
.B \&.mh_sequences
file.

.SS "The Unseen Sequence"
Finally, the unseen sequence indicates which messages have not been
previously seen by the user.
The commands
.BR inc ,
.BR rcvstore ,
.BR show ,
.BR mhshow ,
and
.B flist
honor the sequence.
Whenever new messages are placed in a folder (using
.B inc
or
.BR rcvstore ),
the new messages will also be added to the unseen sequence.
.RE
.PP
.BR inc ,
for example,
adds new messages to the unseen sequence.
Unlike the behavior of the previous sequence, however,
the unseen sequence will
.B not
be zeroed by
.BR inc .
.PP
Similarly, whenever
.BR show ,
.BR mhshow ,
.BR next ,
or
.B prev
display a message, that message will be removed from
the unseen sequence.
.PP
The default unseen sequence is named `u'.
To change, define a \*(lqUnseen\-Sequence\*(rq entry in your profile.
It may also contain multiple sequence names, separated by spaces.
In this case, anything that applied to a single unseen sequence,
applies to multiple ones, too.
.PP
The unseen sequence mechanism is automatically activated.
To deactivate it, define the \*(lqUnseen\-Sequence\*(rq entry
in your profile with an empty value.


.SH FILES
.fc ^ ~
.nf
.ta \w'%etcdir%/ExtraBigFileName  'u
^$HOME/.mmh/profile~^The user profile
^$HOME/.mmh/context~^The user context
^<folder>/\&.mh_sequences~^File for public sequences
.fi

.SH "PROFILE COMPONENTS"
.fc ^ ~
.nf
.ta 2.4i
.ta \w'ExtraBigProfileName  'u
^Mh-Sequences:~^Name of file to store public sequences
^Sequence\-Negation:~^To designate messages not in a sequence
^Previous\-Sequence:~^The last message specification given
^Unseen\-Sequence:~^Those messages not yet seen by the user
.fi

.SH "SEE ALSO"
flist(1), mark(1), pick(1), mh-profile(5)

.SH DEFAULTS
None