variable type in (?{ code }) construction

[p5pRT]

Migrated from rt.perl.org#2030 (status was 'resolved')

Searchable as RT2030$

[p5pRT]

From ishisone@sra.co.jp

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If variable interpolation takes place in a regular expression,
perl seems to consider lexical variables in (?{ code }) construct
as global variables.

The following little script exhibits the problem​:

---

#! /usr/local/bin/perl -w

use strict;
use re 'eval';

my ($a, $x, $y) = ('a', 0, 0);
$_ = 'a';

# No variable interpolation occurs in RE.
# This will print "$x=1" as expected.
/ a (?{ $x = 1 }) /xo and print "\$x=$x\n";

# A variable interpolation occurs in RE.
# This will print "$y=0, $​::y=1" which seems to be a bug.
/ $a (?{ $y = 1 }) /xo and print "\$y=$y, \$​::y=$​::y\n";

---

The output is​:

Name "main​::y" used only once​: possible typo at ./rebug.pl line 15.
$x=1 <-- seems OK
$y=0, $​::y=1 <-- seems wrong

Both $x and $y are lexical, but when evaluating the second RE,
assignment is done to the global variable $​::y.

I also checked with 5.00563, and got the same result.

---

---

This perlbug was built using Perl 5.00503 - Wed May 19 12​:05​:03 JST 1999
It is being executed now by Perl 5.00563 - Tue Jan 25 12​:05​:18 JST 2000.

Site configuration information for perl 5.00503​:

Configured by ishisone at Wed May 19 12​:05​:03 JST 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration​:
  Platform​:
  osname=freebsd, osvers=2.2.8-release, archname=i386-freebsd
  uname='freebsd srapc459.sra.co.jp 2.2.8-release freebsd 2.2.8-release #0​: fri apr 16 11​:14​:40 jst 1999 ishisone@​srapc459.sra.co.jp​:usrsrcsyscompilesrapc459_slim i386 '
  hint=previous, useposix=true, d_sigaction=define
  usethreads=undef useperlio=undef d_sfio=undef
  Compiler​:
  cc='cc', optimize='-O', gccversion=2.7.2.1
  cppflags='-I/usr/local/include'
  ccflags ='-I/usr/local/include'
  stdchar='char', d_stdstdio=undef, usevfork=true
  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='ld', ldflags =' -L/usr/local/lib'
  libpth=/usr/local/lib /usr/lib
  libs=-lm -lxpg4 -lc -lcrypt
  libc=/usr/lib/libc.so.3.1, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
  cccdlflags='-DPIC -fpic', lddlflags='-Bshareable -L/usr/local/lib'

Locally applied patches​:
 

---

@​INC for perl 5.00503​:
  /amd/a/srapc451/mnt3/home/mgr/ishisone/lib/perl5
  /usr/local/lib/perl5/5.00503/i386-freebsd
  /usr/local/lib/perl5/5.00503
  /usr/local/lib/perl5/site_perl/5.005/i386-freebsd
  /usr/local/lib/perl5/site_perl/5.005
  .

---

Environment for perl 5.00503​:
  HOME=/amd/a/srapc451/mnt3/home/mgr/ishisone
  LANG=ja_JP.EUC
  LANGUAGE (unset)
  LC_COLLATE=C
  LC_TIME=C
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/amd/a/srapc451/mnt3/home/mgr/ishisone/bin​:/amd/a/srapc451/mnt3/home/mgr/ishisone/bin/i386-freebsd2​:/usr/X11R6/bin​:/usr/local/bin​:/usr/local/sbin​:/usr/sra/bin​:/usr/local/tdoc/bin​:/usr/local/emacs/bin​:/usr/new/mh​:/usr/local/bin/mh​:/usr/local/v6/bin​:/usr/local/v6/sbin​:/usr/ucb​:/usr/bin​:/usr/new​:/bin​:/etc​:/usr/etc​:/usr/sbin​:/sbin​:/amd/a/srapc451/mnt3/home/mgr/ishisone/bin/lastresort​:
  PERL5LIB=/amd/a/srapc451/mnt3/home/mgr/ishisone/lib/perl5
  PERL_BADLANG (unset)
  SHELL=/usr/local/bin/bash

[p5pRT]

From [Unknown Contact. See original ticket]

Makoto Ishisone writes​:

If variable interpolation takes place in a regular expression,
perl seems to consider lexical variables in (?{ code }) construct
as global variables.

Thanks. This is a known problem. You pinpointed the conditions it
happens under absolutely correct. But nobody could fix it...

Ilya