Re: [Nmh-workers] Relative Message Numbers

[Paul Fox]

ken wrote:
 > >A while back, there was a discussion about
 > >relative message numbers. For example,
 > >http://lists.nongnu.org/archive/html/nmh-workers/2012-10/msg00048.html.
 > >But I don't believe there was a resolution. Was there?
 > >
 > >If foobar is a message sequence then something like foobar+3, for the
 > >third message of foobar, would make my life a bit easier.
 > 
 > I think Paul Fox accurately summed up the consensus view on that
 > thread:
 > 
 >   but i admit:  i've thought about this quite a bit in the past, and
 >   have never come up with syntax that was backward compatible,
 >   meaningful, and enough faster to type than the digits themselves to be
 >   useful.
 > 
 > I don't think the situation has changed.  Right now anything with a
 > "-" in it counts as a range, so there's that to think about.

so, i was using 'dc' the other day (is there anything else?), and for
the first time in a while, i had to enter a negative number.  HP
solved this problem on their calculators with a "CHS" (change sign")
button, but the dc authors opted to require the use of the '_' to
introduce a negative number.

in the face of that long-established and well-recognized precedent :-),
how would people feel about this change:

   The  specification  “name+n”  designates  a  single message, namely the
   `n'th message after `name' (or the last message, if not enough messages
   exist).  One might expect the `n'th message prior to `name' to be spec‐
   ified by “name-n”, but that syntax denotes  a  range.   Therefore,  the
   character  `_'  is used instead:  “name_n” designates the `n'th message
   before `name' (or the first message if not enough messages exist).

i've implemented the above, to see how it "feels" (which is "okay"). 
i can make the corresponding changes for "foobar+3" and "foobar_2" if
folks think it's reasonable.

paul
----------------------
 paul fox, address@hidden (arlington, ma, where it's 50.2 degrees)