PATCH: Re: Bug in zsh-3.1.5 `case' pattern matching

[Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>]

I replied to this on Sunday but it looks like it didn't get to the
list, so I'm assuming it didn't get anywhere.

Martin Birgmeier wrote:
> $ echo echo "${HOSTTYPE:-$OSTYPE}:${TERM}:${TTY}"       <--- informational
> freebsd2.2.7:xterm:/dev/ttyp0
> 
> $ case "${HOSTTYPE:-$OSTYPE}:${TERM}:${TTY}" in        <--- DOES NOT WORK
> freebsd*:xterm:* | freebsd*:xterms:* )
> echo yes
> ;;
> * )
> echo no
> ;;
> esac
> no

The problem was that the pattern matcher didn't know that the `|' was
the end of the pattern, because the alternative after it was
completely separate.  The reason is that `|'s are usually buried
inside parentheses, so aren't the end of a pattern.  That was so in
the old `case' code, which just stuck an open parenthesis in front.
This makes a difference because it needs to know whether the final
part of the pattern, here `*', is forced to reach the end of the test
string.   So Bart's suggestion that there was a parse error is correct.

Luckily the same problem already turned up with `~', the exclusion
pattern, so fixing it with `|' is easy.

*** Src/glob.c.bar	Sun Nov  8 16:03:29 1998
--- Src/glob.c	Sun Nov  8 16:01:28 1998
***************
*** 594,600 ****
  		 pptr[1] && pptr[1] != Outpar && pptr[1] != Bar) ||
  		*pptr == Outpar) {
  		if (*pptr == '/' || !*pptr ||
! 		    (isset(EXTENDEDGLOB) && *pptr == Tilde &&
  		     (gflag & GF_TOPLEV)))
  		    c->stat |= C_LAST;
  		return c;
--- 594,601 ----
  		 pptr[1] && pptr[1] != Outpar && pptr[1] != Bar) ||
  		*pptr == Outpar) {
  		if (*pptr == '/' || !*pptr ||
! 		    ((*pptr == Bar ||
! 		      (isset(EXTENDEDGLOB) && *pptr == Tilde)) &&
  		     (gflag & GF_TOPLEV)))
  		    c->stat |= C_LAST;
  		return c;
***************
*** 746,752 ****
      }
      /* mark if last pattern component in path component or pattern */
      if (*pptr == '/' || !*pptr ||
! 	(isset(EXTENDEDGLOB) && *pptr == Tilde && (gflag & GF_TOPLEV)))
  	c->stat |= C_LAST;
      c->str = dupstrpfx(cstr, pptr - cstr);
      return c;
--- 747,754 ----
      }
      /* mark if last pattern component in path component or pattern */
      if (*pptr == '/' || !*pptr ||
! 	((*pptr == Bar ||
! 	 (isset(EXTENDEDGLOB) && *pptr == Tilde)) && (gflag & GF_TOPLEV)))
  	c->stat |= C_LAST;
      c->str = dupstrpfx(cstr, pptr - cstr);
      return c;

-- 
Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarotti 2, 56100 Pisa, Italy