Hoi.
[2019-12-15 17:55] Philipp Takacs <phil...@bureaucracy.de>
>
> During that I found the Previous-Sequence again. I don't see a reason
> why we need this feature. The usecases, I see, for the feature are better
> handled with mark or the backlog of your shell. But I don't use this
> feature.
Just for reference, the section from mh-sequence(7):
The Previous Sequence
Mmh provides the ability to remember the `msgs' or `msg'
argument last given to an mmh command. The entry `Previ‐
ous-Sequence' should be defined in the mmh profile; its
value should be a sequence name or multiple sequence
names separated by spaces. If this entry is defined,
when an mmh 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
Previous-Sequence: pseq
directs any mmh command that accepts a `msg' or `msgs'
argument to define the sequence `pseq' as those messages
when it finishes.
Note: there can be a performance penalty in using the
`Previous-Sequence' facility. If it is used, all mmh
programs have to write the sequence information to the
.mh_sequences file for the folder each time they run. If
the `Previous-Sequence' profile entry is not included,
only pick and mark will write to the .mh_sequences file.
I myself don't use the previous sequence neither, yet I was
reluctant to throw it away as I wondered if I just haven't
understood it fully enough to find use for it. Also, I have the
feeling that I haven't really understood its reason for existance
well enough.
To me, it seems that it might have been introduced in times before
the shell history feature and today, the shell history covers the
usecase up fully.
The usecase I have in mind is something like:
show 16 25-29 33 34 41-l
refile pseq +foo
However, with shell history and line editing facilities, I simply
do:
Escape k cw refile
to get the second command with out the previous sequence. The
argument set doesn't get lost if you have a shell history.
The shell history covers up the case of a wrong command you like
to undo, too. E.g. I have ``mark unread'' and ``mark read''
commands (which wrap around mark(1)).
And regarding the situation apart from interactive shells with
history, in scripts you'll have the msg arguments in variables
anyways, thus you have them remembered.
This brings me to the conclusion that I don't see a relevant need
for the previous sequence in mmh. I find all the usecaes I can
think of covered otherwise (and more convenient) and I haven't
used the previous sequence myself at all.
Besides: It does introduce a lot of write accesses to the sequence
files.
Before we remove it, I just would like to know why it was
introduced in MH the first time and what possible other usecases
there could be. This means asking on the nmh-workers mailing list.
Both, out of curiosity and as a double-check in case we've not
thought on something. Do you wanna write this message or should
I?
meillo
