-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 According to Eric Blake on 3/17/2009 8:43 AM: > Thanks for the report. I would like to verify these claims before > applying any patches, but agree that they are probably worth mentioning. > >> 1. sed behaves entirely unpredictable on lines that are not newline-terminated. > > Confirmed. POSIX states that sed is only required to operate on text > files, and also that a file without a trailing newline is not a text file. This has actually already been done: http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=b2bde72 >> 2. On HP-UX 11.23, regexp matching with expr does not allow multiple sub- >> expressions: > >> bash-3.1$ expr 'Xfoo' : 'X\(f\(oo\)*\)$' >> expr: More than one '\(' was used. > > Ouch. I don't have access to HP-UX to verify, but this means we need to > audit autoconf source to make sure we don't violate this restriction. > >> 3. On GNU/Linux the regexp "$", when used with older versions of expr, >> matches newlines embedded in the match string: > >> bash-3.1$ baz='foo >> > bar' >> bash-3.1$ expr "X$baz" : 'X\(foo\)$' || echo baz >> foo > > I'm assuming this was from an older version of coreutils? Can someone > determine 'expr --version' in the broken case, to see when it was fixed? Both expr issues are mentioned in this patch, now applied: - -- Don't work too hard, make some time for fun as well! Eric Blake ebb9@xxxxxxx -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAknAT7QACgkQ84KuGfSFAYCb8ACfdcGsMmGLQ/QKlXoBbclnhVAr X6oAoMP2yNoZyxlxLP7eqWzbZqWch0K1 =16+4 -----END PGP SIGNATURE-----
>From abee382683d1b977f2ab4a91121b4277045e6d5a Mon Sep 17 00:00:00 2001 From: Eric Blake <ebb9@xxxxxxx> Date: Tue, 17 Mar 2009 19:33:08 -0600 Subject: [PATCH] Manual: mention more expr pitfalls. * doc/autoconf.texi (Limitations of Usual Tools) <expr (:)>: Mention HP-UX limitation, and $ ambiguity. * THANKS: Update. Reported by Jens Schmidt, in http://bugs.debian.org/466990. Signed-off-by: Eric Blake <ebb9@xxxxxxx> --- ChangeLog | 8 ++++++++ THANKS | 1 + doc/autoconf.texi | 23 +++++++++++++++++++++++ 3 files changed, 32 insertions(+), 0 deletions(-) diff --git a/ChangeLog b/ChangeLog index 259004e..3829924 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2009-03-18 Eric Blake <ebb9@xxxxxxx> + + Manual: mention more expr pitfalls. + * doc/autoconf.texi (Limitations of Usual Tools) <expr (:)>: + Mention HP-UX limitation, and $ ambiguity. + * THANKS: Update. + Reported by Jens Schmidt, in http://bugs.debian.org/466990. + 2009-03-17 Jim Meyering <meyering@xxxxxxxxxx> Manual: fix a typo. diff --git a/THANKS b/THANKS index c3e19a2..8d8bb37 100644 --- a/THANKS +++ b/THANKS diff --git a/doc/autoconf.texi b/doc/autoconf.texi index a0a19b8..a4cb0d1 100644 --- a/doc/autoconf.texi +++ b/doc/autoconf.texi @@ -16642,6 +16642,21 @@ Limitations of Usual Tools @samp{^}. Patterns are automatically anchored so leading @samp{^} is not needed anyway. +On the other hand, the behavior of the @samp{$} anchor is not portable +on multi-line strings. Posix is ambiguous whether the anchor applies to +each line, as was done in older versions of @acronym{GNU} Coreutils, or +whether it applies only to the end of the overall string, as in +Coreutils 6.0 and most other implementations. + +@example +$ @kbd{baz='foo} +> @kbd{bar'} +$ @kbd{expr "X$baz" : 'X\(foo\)$'} + +$ @kbd{expr-5.97 "X$baz" : 'X\(foo\)$'} +foo +@end example + The Posix standard is ambiguous as to whether @samp{expr 'a' : '\(b\)'} outputs @samp{0} or the empty string. In practice, it outputs the empty string on most platforms, but portable @@ -16718,6 +16733,14 @@ Limitations of Usual Tools 1 @end example +On @acronym{HP-UX} 11, @command{expr} only supports a single +sub-expression. + +@example +$ @kbd{expr 'Xfoo' : 'X\(f\(oo\)*\)$'} +expr: More than one '\(' was used. +@end example + @item @command{fgrep} @c ------------------ -- 1.6.1.2
_______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
