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Mar 18, 2008, 8:12 AM
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[perl #51848] Deparse interpolation in regex literal
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# New Ticket Created by Zsban Ambrus
# Please include the string: [perl #51848]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=51848 >
This is a bug report for perl from ambrus[at]math.bme.hu,
generated with the help of perlbug 1.36 running under perl 5.10.0.
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[Please enter your report here]
The following deparse command
perl -MO=Deparse -e '/${x}y/'
gives a wrong output:
/$xy/;
-e syntax OK
This is wrong, because the original script interpolates the variable $x to
the regex, whereas the deparse output interpolates the variable $xy.
Compare the following:
$ perl -MO=Deparse -e '"${x}y"'
"${x}y";
-e syntax OK
$ perl -MO=Deparse,-q -e '"${x}y"'
$x . 'y';
-e syntax OK
$ perl -MO=Deparse -e '/${x}y/'
/$xy/;
-e syntax OK
$ perl -MO=Deparse,-q -e '/${x}y/'
/$xy/;
-e syntax OK
I believe the results for regex literals should be analogous to the string
literals: an interpolated variable name should be braced if the expression
would be ambiguous otherwise. I'm not sure what the -q option should do in
the regex case.
To prove that the regex literal /${x}y/ is parsed right, so this is a
deparse bug, not a parser bug, either examine the Concise output, or
try this:
$ perl -e '$x = "m"; print qr/${x}y/, $/'
(?-xism:my)
$ perl -MO=Deparse -e '$x = "m"; print qr/${x}y/, $/'
$x = 'm';
print qr/$xy/, $/;
-e syntax OK
By the way, this seems to happen in perl 5.10.0, but not in 5.8.8.
Thanks in advance,
Ambrus
[Please do not change anything below this line]
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---
Flags:
category=library
severity=low
---
Site configuration information for perl 5.10.0:
Configured by ambrus at Tue Dec 18 19:35:54 CET 2007.
Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
Platform:
osname=linux, osvers=2.6.20.6, archname=i686-linux
uname='linux king 2.6.20.6 #3 smp tue may 29 09:42:52 cest 2007
i686 gnulinux '
config_args=''
hint=recommended, useposix=true, d_sigaction=define
useithreads=undef, usemultiplicity=undef
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=undef, use64bitall=undef, uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='gcc', ccflags ='-fno-strict-aliasing -pipe
-I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-O2',
cppflags='-fno-strict-aliasing -pipe -I/usr/local/include'
ccversion='', gccversion='4.1.1', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
alignbytes=4, prototype=define
Linker and Libraries:
ld='gcc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib /usr/lib64
libs=-lnsl -ldl -lm -lcrypt -lutil -lc
perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
libc=/lib/libc-2.3.6.so, so=so, useshrplib=false, libperl=libperl.a
gnulibc_version='2.3.6'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib'
Locally applied patches:
---
@INC for perl 5.10.0:
/usr/local/lib/perl5/5.10.0/i686-linux
/usr/local/lib/perl5/5.10.0
/usr/local/lib/perl5/site_perl/5.10.0/i686-linux
/usr/local/lib/perl5/site_perl/5.10.0
/usr/local/lib/perl5/site_perl/5.8.8
/usr/local/lib/perl5/site_perl
.
---
Environment for perl 5.10.0:
HOME=/home/ambrus
LANG (unset)
LANGUAGE=en_HU:en_US:en_GB:en
LC_CTYPE=hu_HU
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/home/ambrus/local/bin:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games
PERL_BADLANG (unset)
SHELL=/bin/bash
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