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[ID 20010827.004] qw// documentation says a list is created
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From:
Ren Maddox
Date:
August 27, 2001 08:32
Subject:
[ID 20010827.004] qw// documentation says a list is created
Message ID:
200108271529.f7RFTkw24601@dhcp9-161.support.tivoli.com
This is a bug report for perl from ren@tivoli.com,
generated with the help of perlbug 1.33 running under perl v5.6.1.
-----------------------------------------------------------------
The documentation of qw// states that a list is created. It needs
to be reworded in terms of context. Here's one attempt:
qw/STRING/
Evaluates to a sequence of comma-separated,
single-quoted sub-strings extracted out of STRING,
using embedded whitespace as the delimiters.
In list context, it can be understood as being roughly
equivalent to:
split(' ', q/STRING/, -1);
the difference being that it happens at compile time.
In scalar context, it evaluates to the final sub-string
of the sequence.
So this expression:
qw(foo bar baz)
is semantically equivalent to this one:
('foo', 'bar', 'baz')
in both list and scalar contexts (evaluating to a list
of the three elements in list context and 'baz' in
scalar context).
Some frequently seen examples:
use POSIX qw( setlocale localeconv )
@EXPORT = qw( foo bar baz );
A common mistake is to try to separate the words
with comma or to put comments into a multi-line
"qw"-string. For this reason, the "use warnings"
pragma and the -w switch (that is, the "$^W" vari
able) produces warnings if the STRING contains the
"," or the "#" character.
-----------------------------------------------------------------
---
Flags:
category=docs
severity=medium
---
Site configuration information for perl v5.6.1:
Configured by daves at Wed Jul 4 15:34:35 PDT 2001.
Summary of my perl5 (revision 5.0 version 6 subversion 1) configuration:
Platform:
osname=linux, osvers=2.2.12-20smp, archname=i686-linux-thread-multi
uname='linux molotok 2.2.12-20smp #1 smp mon sep 27 10:34:45 edt 1999 i686 unknown '
config_args='-des -Dcc=gcc -Dcf_by=ActiveState -Dcf_email=ActivePerl@ActiveState.com -Uinstallusrbinperl -Dusethreads -Duseithreads -Dinc_version_list=5.6.0/$archname 5.6.0 -Dprefix=/usr/local/ActivePerl-5.6'
hint=recommended, useposix=true, d_sigaction=define
usethreads=define use5005threads=undef useithreads=define usemultiplicity=define
useperlio=undef d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
Compiler:
cc='gcc', ccflags ='-D_REENTRANT -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-O2',
cppflags='-D_REENTRANT -fno-strict-aliasing -I/usr/local/include'
ccversion='', gccversion='egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)', 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, usemymalloc=n, prototype=define
Linker and Libraries:
ld='gcc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib
libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lpthread -lc -lposix -lcrypt -lutil
perllibs=-lnsl -ldl -lm -lpthread -lc -lposix -lcrypt -lutil
libc=/lib/libc-2.1.2.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:
ACTIVEPERL_LOCAL_PATCHES_ENTRY
---
@INC for perl v5.6.1:
/usr/local/ActivePerl-5.6/lib/5.6.1/i686-linux-thread-multi
/usr/local/ActivePerl-5.6/lib/5.6.1
/usr/local/ActivePerl-5.6/lib/site_perl/5.6.1/i686-linux-thread-multi
/usr/local/ActivePerl-5.6/lib/site_perl/5.6.1
/usr/local/ActivePerl-5.6/lib/site_perl/5.6.0/i686-linux-thread-multi
/usr/local/ActivePerl-5.6/lib/site_perl/5.6.0
/usr/local/ActivePerl-5.6/lib/site_perl
.
---
Environment for perl v5.6.1:
HOME=/home/ren
LANG=en_US
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/usr/local/ActivePerl-5.6/bin:/home/ren/bin:/home/ren/perl:/home/ren/scripts:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/X11R6/bin:/usr/local/office52:/home/ren/bin:/usr/lpp/cmvc/bin:/net/snapper/opt/AusTextTools:.
PERL_BADLANG (unset)
SHELL=/bin/zsh
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[ID 20010827.004] qw// documentation says a list is created
by Ren Maddox