[bug? 5.6.0] \G in split pattern #3029

p5pRT · 2000-12-23T08:12:51Z

Migrated from rt.perl.org#5004 (status was 'open')

Searchable as RT5004$

p5pRT · 2000-12-23T08:12:51Z

From @hvds

Created by @hvds

[fixed misassigned from/created after github migration]

Not sure if this is a bug, but I thought it worth mentioning for
consideration.

crypt% ./perl -wle 'print join "*", split /\G(an|.)/, shift' banana
*b*anana
crypt%

I had hoped it would print something like "*b**an**an**a*". Result
is the same under bleadperl.

Perl Info


Flags:
    ack=no
    category=core
    severity=low

Site configuration information for perl v5.6.0:

Configured by hv at Thu Mar 23 11:41:17 GMT 2000.

Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.2.5-16, archname=i686-linux-64int
    uname='linux crypt.compulink.co.uk 2.2.5-16 #1 sun may 30 23:00:18 bst 1999 i686 unknown '
    config_args='-des -Doptimize=-g -O6 -Dprefix=/opt/perl-5.6.0.64bit -Duse64bitint'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=define 
    use64bitint=define use64bitall=undef uselongdouble=undef usesocks=undef
  Compiler:
    cc='cc', optimize='-g -O6', gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
    cppflags='-DDEBUGGING -fno-strict-aliasing'
    ccflags ='-DDEBUGGING -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    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 -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt
    libc=/lib/libc-2.1.1.so, 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'

Locally applied patches:
    


@INC for perl v5.6.0:
    /opt/perl-5.6.0.64bit/lib/5.6.0/i686-linux-64int
    /opt/perl-5.6.0.64bit/lib/5.6.0
    /opt/perl-5.6.0.64bit/lib/site_perl/5.6.0/i686-linux-64int
    /opt/perl-5.6.0.64bit/lib/site_perl/5.6.0
    /opt/perl-5.6.0.64bit/lib/site_perl
    .


Environment for perl v5.6.0:
    HOME=/home/hv
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/hv/bin:/usr/bin:/usr/local/bin:/bin:/usr/X11R6/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

p5pRT · 2010-04-28T20:44:15Z

From @chorny

Same result on 5.12.0.

On Sat Dec 23 00:12:51 2000, hv@crypt.compulink.co.uk wrote:

Not sure if this is a bug, but I thought it worth mentioning for
consideration.

crypt% ./perl -wle 'print join "*", split /\G(an|.)/, shift' banana
*b*anana
crypt%

I had hoped it would print something like "*b**an**an**a*". Result
is the same under bleadperl.

--
Alexandr Ciornii, http://chorny.net

p5pRT · 2010-04-28T20:44:15Z

From [Unknown Contact. See original ticket]

Same result on 5.12.0.

On Sat Dec 23 00:12:51 2000, hv@crypt.compulink.co.uk wrote:

Not sure if this is a bug, but I thought it worth mentioning for
consideration.

crypt% ./perl -wle 'print join "*", split /\G(an|.)/, shift' banana
*b*anana
crypt%

I had hoped it would print something like "*b**an**an**a*". Result
is the same under bleadperl.

--
Alexandr Ciornii, http://chorny.net

p5pRT · 2016-07-04T03:30:46Z

From @dcollinsn

Is \G intended to be meaningful in an argument to split? Instrumenting two variations tells me that \G and pos() do not work within split//:

dcollins@nightshade64:~/toolchain/perl/t$ ./perl -Dr -le 'print join("*", split(/(?{print "POS: " . pos() . "\n";})\G(.)/, "banana"))'
Compiling REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)"
Final program:
1: EVAL (4)
4: GPOS (5)
5: OPEN1 (7)
7: REG_ANY (8)
8: CLOSE1 (10)
10: END (0)
anchored(GPOS) GPOS:0 minlen 1 with eval
Enabling $` $& $' support (0x7).

EXECUTING...

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "banana"
0 <> <banana> | 0| 1:EVAL(4)
POS: 0

0 <> <banana> | 0| 4:GPOS(5)
0 <> <banana> | 0| 5:OPEN1(7)
0 <> <banana> | 0| 7:REG_ANY(8)
1 <anana> | 0| 8:CLOSE1(10)
1 <anana> | 0| 10:END(0)
Match successful!
Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "anana"
0 <> <banana> | 0| 1:EVAL(4)
POS: 0

0 <> <banana> | 0| 4:GPOS(5)
0 <> <banana> | 0| 5:OPEN1(7)
0 <> <banana> | 0| 7:REG_ANY(8)
1 <anana> | 0| 8:CLOSE1(10)
1 <anana> | 0| 10:END(0)
Match possible, but length=1 is smaller than requested=2, failing!
Match failed
*b*anana

dcollins@nightshade64:~/toolchain/perl/t$ ./perl -Dr -le 'while ("banana" =~ /(?{print "POS: " . pos() . "\n";})\G(.)/g) {print "$&\n";}'
Compiling REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)"
Final program:
1: EVAL (4)
4: GPOS (5)
5: OPEN1 (7)
7: REG_ANY (8)
8: CLOSE1 (10)
10: END (0)
anchored(GPOS) GPOS:0 minlen 1 with eval
Enabling $` $& $' support (0x7).

EXECUTING...

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "banana"
0 <> <banana> | 0| 1:EVAL(4)
POS: 0

0 <> <banana> | 0| 4:GPOS(5)
0 <> <banana> | 0| 5:OPEN1(7)
0 <> <banana> | 0| 7:REG_ANY(8)
1 <anana> | 0| 8:CLOSE1(10)
1 <anana> | 0| 10:END(0)
Match successful!
b

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "anana"
1 <anana> | 0| 1:EVAL(4)
POS: 1

1 <anana> | 0| 4:GPOS(5)
1 <anana> | 0| 5:OPEN1(7)
1 <anana> | 0| 7:REG_ANY(8)
2 <ba> <nana> | 0| 8:CLOSE1(10)
2 <ba> <nana> | 0| 10:END(0)
Match successful!
a

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "nana"
2 <ba> <nana> | 0| 1:EVAL(4)
POS: 2

2 <ba> <nana> | 0| 4:GPOS(5)
2 <ba> <nana> | 0| 5:OPEN1(7)
2 <ba> <nana> | 0| 7:REG_ANY(8)
3 <ban> <ana> | 0| 8:CLOSE1(10)
3 <ban> <ana> | 0| 10:END(0)
Match successful!
n

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "ana"
3 <ban> <ana> | 0| 1:EVAL(4)
POS: 3

3 <ban> <ana> | 0| 4:GPOS(5)
3 <ban> <ana> | 0| 5:OPEN1(7)
3 <ban> <ana> | 0| 7:REG_ANY(8)
4 <bana> <na> | 0| 8:CLOSE1(10)
4 <bana> <na> | 0| 10:END(0)
Match successful!
a

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "na"
4 <bana> <na> | 0| 1:EVAL(4)
POS: 4

4 <bana> <na> | 0| 4:GPOS(5)
4 <bana> <na> | 0| 5:OPEN1(7)
4 <bana> <na> | 0| 7:REG_ANY(8)
5 <banan> <a> | 0| 8:CLOSE1(10)
5 <banan> <a> | 0| 10:END(0)
Match successful!
n

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against "a"
5 <banan> <a> | 0| 1:EVAL(4)
POS: 5

5 <banan> <a> | 0| 4:GPOS(5)
5 <banan> <a> | 0| 5:OPEN1(7)
5 <banan> <a> | 0| 7:REG_ANY(8)
6 <banana> <> | 0| 8:CLOSE1(10)
6 <banana> <> | 0| 10:END(0)
Match successful!
a

Matching REx "(?{print %"POS: %" . pos() . %"\n%";})\G(.)" against ""
Regex match can't succeed, so not even tried

Is this /supposed/ to work? is pos() or \G in any way a feature that is useful in split//?

demerphq · 2023-02-10T05:54:45Z

/g is not allowed on a split argument, which i think might fix this. I am torn about whether we should fix this TBH.

p5pRT added Severity Low distro-Linux type-library labels Oct 18, 2019

xenu removed affects-5.6 labels Nov 19, 2021

xenu removed the Severity Low label Dec 29, 2021

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[bug? 5.6.0] \G in split pattern #3029

[bug? 5.6.0] \G in split pattern #3029

p5pRT commented Dec 23, 2000

p5pRT commented Dec 23, 2000 •

edited by hvds

p5pRT commented Apr 28, 2010

p5pRT commented Apr 28, 2010

p5pRT commented Jul 4, 2016

demerphq commented Feb 10, 2023

[bug? 5.6.0] \G in split pattern #3029

[bug? 5.6.0] \G in split pattern #3029

Comments

p5pRT commented Dec 23, 2000

p5pRT commented Dec 23, 2000 • edited by hvds

From @hvds

Created by @hvds

p5pRT commented Apr 28, 2010

From @chorny

p5pRT commented Apr 28, 2010

From [Unknown Contact. See original ticket]

p5pRT commented Jul 4, 2016

From @dcollinsn

demerphq commented Feb 10, 2023

p5pRT commented Dec 23, 2000 •

edited by hvds