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[perl #54974] Strange map {} Behavior When Returning Two Values
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From:
David Wheeler
Date:
May 29, 2008 03:37
Subject:
[perl #54974] Strange map {} Behavior When Returning Two Values
Message ID:
rt-3.6.HEAD-11257-1211991743-1688.54974-75-0@perl.org
# New Ticket Created by David Wheeler
# Please include the string: [perl #54974]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=54974 >
perlbug,
This is a bug report for perl from david@kineticode.com,
generated with the help of perlbug 1.36 running under perl 5.10.0.
-----------------------------------------------------------------
When I run this code:
my @a = map { "--$_" => $_ } @ARGV;
I get this compile-time error:
Not enough arguments for map at /Users/david/bin/try line 6, near "} @ARGV"
syntax error at /Users/david/bin/try line 6, near "} @ARGV"
Execution of /Users/david/bin/try aborted due to compilation errors.
When I change the map to:
my @a = map { '--' . $_ => $_ } @ARGV;
It works. The only difference is using concatentation instead of the double-quoted string "--$_".
Curiously, I don't get the compile-time error for this code:
my @a = map { "--$_" } @ARGV;
So it seems to be something about returning two values from the map sub.
FWIW, I get a similar error with Perl 5.8.8:
syntax error at /Users/david/bin/try line 6, near "} @ARGV"
Execution of /Users/david/bin/try aborted due to compilation errors.
I'm fine to use the concatenation workaround, but it seems pretty bizarre, and so worth reporting.
Thanks!
David
-----------------------------------------------------------------
---
Flags:
category=core
severity=low
---
Site configuration information for perl 5.10.0:
Configured by david at Mon Apr 14 12:06:56 PDT 2008.
Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
Platform:
osname=darwin, osvers=9.2.2, archname=darwin-2level
uname='darwin benedict.local 9.2.2 darwin kernel version 9.2.2: tue mar 4 21:17:34 pst 2008; root:xnu-1228.4.31~1release_i386 i386 '
config_args='-des -Duseshrplib -Dperladmin=david@kineticode.com -Dcf_email=david@kineticode.com'
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='cc', ccflags ='-fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -I/usr/local/include',
optimize='-O3',
cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -I/usr/local/include'
ccversion='', gccversion='4.0.1 (Apple Inc. build 5465)', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib
libs=-ldbm -ldl -lm -lutil -lc
perllibs=-ldl -lm -lutil -lc
libc=/usr/lib/libc.dylib, so=dylib, useshrplib=true, libperl=libperl.dylib
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib'
Locally applied patches:
---
@INC for perl 5.10.0:
/usr/local/lib/perl5/5.10.0/darwin-2level
/usr/local/lib/perl5/5.10.0
/usr/local/lib/perl5/site_perl/5.10.0/darwin-2level
/usr/local/lib/perl5/site_perl/5.10.0
.
---
Environment for perl 5.10.0:
DYLD_LIBRARY_PATH (unset)
HOME=/Users/david
LANG=en_US.UTF-8
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/opt/local/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/Developer/Tools:/Users/david/bin:/usr/local/pgsql/bin:/usr/local/mysql/bin:/usr/X11/bin
PERL_BADLANG (unset)
SHELL=/bin/zsh
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