Re: check if message is in a particular sequence?

[Ralph Corderoy]

Hi Paul,

> > >     $ mark -list 2-6    <-- previously behaved as "mark -list", above
> > >     odd: 3 5
> > >     even: 2 4 6
> > 
> > I would have expected an extra line,
> > 
> >     $ mark -list 2-6
> >  +  cur: 
> >     odd: 3 5
> >     even: 2 4 6
> > 
> > because the messages given are being intersected with the normal
> > ‘mark -list’ output you showed at the start above.
>
> The current behavior matches my requirements, and the (new)
> description in the man page describes it.

Naturally.  :-)

> I wasn't thinking of it as an intersection, but a membership listing:
>
>    "If msgs are specified, then only the sequence memberships for the
>     given messages are shown, either for all sequences, or just for
>     those named by -sequence switches."
>
> > IOW, if no messages are given then the default is ‘all’.  This seems
> > more orthogonal to me and means a script can give multiple sequences
> > and expect one line for each in the output in the order the
> > sequences were stated; there's no need to parse the ‘foo:’ or ‘bar
> > (private):’ to identify the sequence involved.
>
> I understand your need.  How about if adding "-zero" caused sequences
> in which the named messages aren't members to be listed as well?
> I.e., "include sequences with 'zero' results", The -zero switch is
> already overused by delete (to mean, "invert"), so I don't think this
> is too big a leap.  New (additional) man description:
>
>    "Normally sequences in which none of the given msgs are members are
>     suppressed in the output.  The -zero switch will cause all
>     sequences mentioned on the command line to be listed, whether or
>     not they include any of the specified messages."

My suggested behaviour:

- Using -list shows sequences and the messages in them.
- If any -sequences are given then only those sequences are listed
  rather than all sequences.
- If any messages are given then only those messages will be shown
  rather than all messages.

I don't need to describe the interaction of those two cases because they
combine in the natural manner; they're orthogonal to each other.
(The code may well echo that lack of intertwining.)

You're suggesting not listing sequences with zero messages.  The
existing -zero/-nozero option's default is -nozero but mark's existing
behaviour is to list sequences with zero messages so the meaning doesn't
match.  (And the overloading of -zero for -delete's use has always
seemed confusing and non-obvious to me.  :-)

A new -empty/-noempty could state whether to list empty sequences.
Default -empty to keep the existing behaviour.

> > An example not given here would be empty sequences, i.e. ones which
> > don't exist.  Currently:
> > 
> >     $ mark -l -s cur -s foo -s bar -s xyzzy
> >     cur: 96894
> >     foo: 
> >     bar: 97036
> >     xyzzy: 
>
> Is this actually the desired behavior?  Shouldn't mark instead complain
> with "mark: no such sequence as xyzzy"?

That would be annoying if I want to know which sequences are empty.
Would mark(1) state that on stderr and stop or keep going on stdout for
non-empty sequences?  Does stderr get just the first one which doesn't
exist, or all of them?  Just the first means a script would have to
adjust and re-run until stderr is empty as well as capturing both stdout
and stderr.

(It's an annoying artefact of MH's implementation that an empty sequence
is deleted and thus indistinguishable from a typo'd sequence.  It's like
not having the number zero.)

> I hadn't realized that mark was currently silent about this, and my
> patch is not silent like that, when messages are provided:
>
>     $ mark -l -s odd -s xyzzy 
>     odd: 1 3 5 7 9
>     xyzzy: 
>     $ mark -l -s odd -s xyzzy 1
>     odd: 1
>     mark: no such sequence as xyzzy
>
> The behaviors should clearly match.

Yes.

> I think I'd prefer the error, but you can try to convince me..

You'd be changing existing behaviour.

>  > BTW, ‘first’, etc., aren't sequences, as we know.
>  > 
>  >     $ p -seq first 42
>  >     pick: sequence name is reserved: first
>  > 
>  > Yet,
>  > 
>  >     $ mark -l -s first -s cur -s last -s foo -s bar -s xyzzy
>  >     first: 
>  >     cur: 96894
>  >     last: 
>  >     foo: 
>  >     bar: 97036
>  >     xyzzy: 
>  >     $ 
>  > 
>  > mark(1) doesn't complain and I'd expect it to as pick does.
>
> I agree that it should be an error.  And again, it seems that if
> "first" is in error, then "xyzzy" should also be considered an error.

I don't think so because ‘first’ is a reserved word, as the error says,
whereas ‘xyzzy’ isn't.  (Though surely we can think of some meaning and
make is so.  :-)

-- 
Cheers, Ralph.