On 2/21/25 10:13 AM, Robert Elz wrote:
Date: Fri, 21 Feb 2025 09:08:13 -0500 From: Chet Ramey <chet.ra...@case.edu> Message-ID: <59a1d1d0-b6eb-4652-9e77-1fc4c5992...@case.edu>| Given the following, which POSIX says is unspecified: | | printf '%s %3$s %s\n' A B C D | | ksh93-u+m prints "A D", which is just wrong. It actually prints "A D \n" (the \n is obvious, and unimportant, but the extra space makes a big difference). | No matter how you mix numbered | and unnumbered specifications, or whether you implement numbered | specifications at all, you can't just drop it. It isn't, and while bizarre indeed, that's a defensible operation. As you say, this is all unspecified in POSIX, which means anything is acceptable - here it looks as of the "%3$" is counting the args after args used already for unnumbered conversions have already been removed, since the A has already been consumed, the remaining args areB C D, so the third is D.
That is bizarre and indefensible. There is no user who would think that using a numbered conversion specifier is not an absolute position in the original argument list. ksh93 seems to be alone in its interpretation.
I abandoned my plans on implementing the numbered conversions when POSIX insisted that even in the presence of numbered arg conversions, if all the args aren't consumed by the format, the format string needs to be repeated, the same as is done when there are no numbered conversions.
It's worse -- even if a format string using only numbered conversions
doesn't consume all the arguments, as long as it consumes the last one,
the format string doesn't get reused. It all depends on whatever peculiar
definition of "satisfy" you use.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
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