[ID 20000420.007] weird matching in while //g

This is a bug report for perl from cristi@obs-us.com,
generated with the help of perlbug 1.26 running under perl 5.00502.


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[Please enter your report here]

Hello perl porters,

I am trying to match in a string (file buffer) and as I like to write
code in as little characters as possible I had the matching expression
in one line like:

	function while match;

But I wasn't getting the right result so I tryed couple of different tests
till I realized what happens. I enclosed a little example program that
shows what I might stumbled upon. I don't know if this is realy a bug, but I 
consider it so since I didn't find any explanation in the man page about 
a possible feature or limitation. Anyhow I didn't search thorougly as I went
many times over the man page and books and I would've remembered such thing.


cheers,
cristi

P.S. Same thing on 5.6.0 on WinNT




#!/usr/local/bin/perl5

$a = "AA\r\nBB";
$b = "A\r\n";

$da = $a;
$db = $b;

$da =~ s/\r/\\r/g; $da =~ s/\n/\\n/g;
$db =~ s/\r/\\r/g; $db =~ s/\n/\\n/g;

print "a: $da\n";
print "b: $db\n";

print "OK match follows\n";

while ( $a =~ /$b/g )
{
        $p = $`;
        $m = $&;
        $n = $';

        $p =~ s/\r/\\r/g; $p =~ s/\n/\\n/g;
        $m =~ s/\r/\\r/g; $m =~ s/\n/\\n/g;
        $n =~ s/\r/\\r/g; $n =~ s/\n/\\n/g;

        print "MATCH p:$p\n";
        print "MATCH m:$m\n";
        print "MATCH n:$n\n";
}

print "WRONG match follows\n";

do {
        $p = $`;
        $m = $&;
        $n = $';

        $p =~ s/\r/\\r/g; $p =~ s/\n/\\n/g;
        $m =~ s/\r/\\r/g; $m =~ s/\n/\\n/g;
        $n =~ s/\r/\\r/g; $n =~ s/\n/\\n/g;

        print "MATCH p:$p\n";
        print "MATCH m:$m\n";
        print "MATCH n:$n\n";
}
while $a =~ /$b/g;


1;


Produces:


a: AA\r\nBB
b: A\r\n

OK matching follows
MATCH p:A
MATCH m:A\r\n
MATCH n:BB

WRONG matching follows
MATCH p:A\r
MATCH m:\n
MATCH n:
MATCH p:A
MATCH m:A\r\n
MATCH n:BB




[Please do not change anything below this line]
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---
Site configuration information for perl 5.00502:

Configured by storm at Mon Mar  8 16:58:30 EST 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 2) configuration:
  Platform:
    osname=solaris, osvers=2.7, archname=sun4-solaris-thread
    uname='sunos salvages 5.7 generic sun4u sparc sunw,ultra-5_10 '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='-O', gccversion=2.8.1
    cppflags='-D_REENTRANT -I/usr/local/include'
    ccflags ='-D_REENTRANT -I/usr/local/include'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    alignbytes=8, usemymalloc=y, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib
    libs=-lsocket -lnsl -ldl -lm -lposix4 -lpthread -lc -lcrypt
    libc=/lib/libc.so, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-fPIC', lddlflags='-G -L/usr/local/lib'

Locally applied patches:
    

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@INC for perl 5.00502:
    /usr/local/lib/perl5/5.00502/sun4-solaris-thread
    /usr/local/lib/perl5/5.00502
    /usr/local/lib/perl5/site_perl/5.005/sun4-solaris-thread
    /usr/local/lib/perl5/site_perl/5.005
    .

---
Environment for perl 5.00502:
    HOME=/export/home/systems/tech/cristi
    LANG (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/ucb:/usr/gnu/bin:/bin:/usr/bin:/usr/ucb:/usr/bin/X11:/usr/local/bin:/usr/local/bin:/usr/local/bin:/usr/sbin:/usr/bin:/usr/local/bin:/bin:/usr/xpg4/bin:/opt/RICHPse/examples:/usr/ccs/bin:/usr/openwin/bin:.
    PERL_BADLANG (unset)
    SHELL=/usr/local/bin/bash

• [ID 20000420.007] weird matching in while //g by Cristi
• Re: [ID 20000420.007] weird matching in while //g by Ronald J Kimball