Date: Sun, 16 Mar 2025 02:35:12 +0100
From: Steffen Nurpmeso <stef...@sdaoden.eu>
Message-ID: <20250316013512.2aC3SIyk@steffen%sdaoden.eu>
| The problem is not an empty field.
Your problem might not be, but it all derives from that.
| The problem is that ":a:" has to be splitted to ""+a by itself, not to
| ""+a+"", as the second : only delimits the "a".
Sure, and if that was the input, that would be what happens. But it
isn't that ":a:" is an apparent internal implementation artifact, and
what happens with that isn't specified anywhere.
As I said in another message, I could explain (at least what happens
in the NetBSD sh, not what happens in bash necessarily, that might be
quite different) but I doubt it would help, and it certainly wouldn't
be appropriate for bug-bash.
| But say, isn't ksh88 the template for POSIX,
It was, but ksh88 is so seldom seen any more that its influence
has waned.
| and if so, is the above standard saying now ksh88 and all the
| shells deviate,
No, the standards writer noticed that shells did different things in
this area, and as they couldn't convince everyone to change, they
simply made the behaviour (semi-)unspecified (not really, as there
aren't arbitrary choices allowed, just to drop an empty field or not).
| or is the above one of those not "sooo" seldom
| occasions where application behaviour was not hundred percent
| correctly taken over to the initial standard document?
I haven't looked back to see what the first SUS said about this
(if I even have access to an early enough version), but that's
ancient now, and no longer of any real relevance to anything.
| In the latter case there should be an issue.
Issue related to what? There are LOTS of places (in the shell, and
elsewhere) where variant behaviour exists, and is documented as existing.
Another (which happened to just come up in an entirely unrelated context,
earlier this morning (here)) is that the pre and post decrement C arith
operators aren't required to be implemented in $(( )) expansions. They
can be, or they can be omitted. There are shells that do each.
There's nothing odd here, except perhaps that the one standard is attempting
to both specify what users can expect to work in existing (conforming)
implementations, and what new implementations should implement, and sometimes
can't quite work out which of those is more important.
| This was, if i recall correctly, about the "empty fields *may* be
| discarded".
Yes.
| And that is not the issue here.
But it is, you've just ventured so far down the rabbit hole that you're
not seeing that.
| at least real Spring is only three to four days ahead!!
Here we have about a month to go before the middle of summer (or
maybe the start of summer is in a few days, perhaps, the hottest
period will be in about a month.) I doubt that will affect $*
expansions though.
kre
