SPUG: Strange regex problem

[Andrew Crum]

I have 2 Linux boxes, one with Perl 5.00503 &the other with Perl 5.6.0.
So I tried your code on both boxies...
  Perl 5.00503  -- gi problem re-created.
  Perl 5.6.0    -- no problem with gi.
- Andrew

======
SPUGers,

   I'm working with a substitution regex that correctly does a
substitution, but the $1, $2, etc. that I expect are empty when I use
the //i and //g modifiers together.  I am hoping that one of you may
have seen this before and have a good explanation; why would they react
to one another?  Please ignore that the //i and //g are pointless in my
example, except for demonstrating this problem.  Here is an example of
what I'm talking about (using the ever-so-cute abc regex):

# Just using //i here
bash$ perl -e '$foo = "abcdefghijklmnopqrstuvwxyz"; $foo =~
s/(hi)(.*)(stu)/$3$2$1/i; print "$1, $3!\n$foo\n"'
hi, stu!
abcdefgstujklmnopqrhivwxyz

# //g here, and still no problems with $1, $2, and $3
bash$ perl -e '$foo = "abcdefghijklmnopqrstuvwxyz"; $foo =~
s/(hi)(.*)(stu)/$3$2$1/g; print "$1, $3!\n$foo\n"'
hi, stu!
abcdefgstujklmnopqrhivwxyz

#  Whoops!  //gi is acting fishy...
bash$ perl -e '$foo = "abcdefghijklmnopqrstuvwxyz"; $foo =~
s/(hi)(.*)(stu)/$3$2$1/gi; print "$1, $3!\n$foo\n"'
, !
abcdefgstujklmnopqrhivwxyz


Thanks for any light you can shed on this,
--
Trevor Leffler, Software Developer
PETTT, University of Washington
Box 353080, (206) 616-3406 FAX: (206) 616-2873


bash$ perl -V
Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
   Platform:
     osname=linux, osvers=2.2.5-22smp, archname=i386-linux
     uname='linux porky.devel.redhat.com 2.2.5-22smp #1 smp wed jun 2
09:11:51 edt 1999 i686 unknown '
     hint=recommended, useposix=true, d_sigaction=define
     usethreads=undef useperlio=undef d_sfio=undef
   Compiler:
     cc='cc', optimize='-O2 -m486 -fno-strength-reduce',
gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
     ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
     stdchar='char', d_stdstdio=undef, usevfork=false
     intsize=4, longsize=4, ptrsize=4, doublesize=8
     d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
     alignbytes=4, usemymalloc=n, prototype=define
   Linker and Libraries:
     ld='cc', ldflags =' -L/usr/local/lib'
     libpth=/usr/local/lib /lib /usr/lib
     libs=-lnsl -ldl -lm -lc -lposix -lcrypt
     libc=, so=so, useshrplib=false, libperl=libperl.a
   Dynamic Linking:
     dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
     cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl):
   Built under linux
   Compiled at Aug 10 2000 15:33:00
   @INC:
     /usr/lib/perl5/5.00503/i386-linux
     /usr/lib/perl5/5.00503
     /usr/lib/perl5/site_perl/5.005/i386-linux
     /usr/lib/perl5/site_perl/5.005

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