From @ikegami

Created by @ikegami

perlsyn indicates that "when (/REGEX/)" is treated as "when ($_ =~ /REGEX/)"
instead of "when ($_ ~~ /REGEX/)". Why? It seems to me the latter would be
more useful.

------ BEGIN EXAMPLE -----
use 5.010; # say, switch
use strict;
use warnings;

my @​a = qw(abc def);

if (@​a ~~ /abc/ ) { say '/abc/'; } # Matches
if (@​a ~~ qr/abc/) { say 'qr/abc/'; } # Matches
if (@​a ~~ /ARRAY/) { say '/ARRAY/'; } # Doesn't match

say '--';

given (@​a) {
  when (/abc/ ) { say '/abc/'; continue; } # Doesn't match!!!
  when (qr/abc/) { say 'qr/abc/'; continue; } # Matches
  when (/ARRAY/) { say '/ARRAY/'; continue; } # Matches!!!
}

say '--';

given ($a[0]) {
  when (/abc/ ) { say '/abc/'; continue; } # Matches
  when (qr/abc/) { say 'qr/abc/'; continue; } # Matches
}
------ END EXAMPLE -----

------ BEGIN OUTPUT -----
/abc/
qr/abc/
--
qr/abc/
/ARRAY/
--
/abc/
qr/abc/
------ END OUTPUT -----

Flags:
    category=core
    severity=low

Site configuration information for perl 5.12.0:

Configured by eric at Tue May  4 17:51:08 EDT 2010.

Summary of my perl5 (revision 5 version 12 subversion 0) configuration:

  Platform:
    osname=linux, osvers=2.6.26-2-686, archname=i686-linux
    uname='linux fmdev10 2.6.26-2-686 #1 smp tue mar 9 17:35:51 utc 2010
i686 gnulinux '
    config_args='-de -Dprefix=/home/eric/usr/perlbrew/perls/perl-5.12.0'
    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-strict-aliasing -pipe -fstack-protector
-I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-fno-strict-aliasing -pipe -fstack-protector
-I/usr/local/include'
    ccversion='', gccversion='4.3.2', 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='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -ldl -lm -lcrypt -lutil -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.7.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.7'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib
-fstack-protector'

Locally applied patches:



@INC for perl 5.12.0:

/home/eric/usr/perlbrew/perls/perl-5.12.0/lib/site_perl/5.12.0/i686-linux
    /home/eric/usr/perlbrew/perls/perl-5.12.0/lib/site_perl/5.12.0
    /home/eric/usr/perlbrew/perls/perl-5.12.0/lib/5.12.0/i686-linux
    /home/eric/usr/perlbrew/perls/perl-5.12.0/lib/5.12.0
    .


Environment for perl 5.12.0:
    HOME=/home/eric
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)

PATH=/home/eric/usr/perlbrew/bin:/home/eric/usr/perlbrew/perls/current/bin:.:/home/eric/bin:/usr/local/bin:/usr/bin:/bin:/usr/games
    PERLBREW_ROOT=/home/eric/usr/perlbrew
    PERL_BADLANG (unset)
    SHELL=/bin/bash

From @obra

Confirmed as giving the same output on 5.12.1

The RT System itself - Status changed from 'new' to 'open'

From @cpansprout

On Thu Jul 22 09​:14​:47 2010, ikegami@​adaelis.com wrote​:

given (@​a) {
when (/abc/ ) { say '/abc/'; continue; } # Doesn't match!!!
when (qr/abc/) { say 'qr/abc/'; continue; } # Matches
when (/ARRAY/) { say '/ARRAY/'; continue; } # Matches!!!
}

Under the new scheme, given($array_ref) won’t be particularly
meaningful, will it?

So should given(@​a) continue to turn automagically into given(\@​a)?

--

Father Chrysostomos

From @doy

On Tue, Sep 11, 2012 at 10​:34​:14PM -0700, Father Chrysostomos via RT wrote​:

On Thu Jul 22 09​:14​:47 2010, ikegami@​adaelis.com wrote​:

given (@​a) {
when (/abc/ ) { say '/abc/'; continue; } # Doesn't match!!!
when (qr/abc/) { say 'qr/abc/'; continue; } # Matches
when (/ARRAY/) { say '/ARRAY/'; continue; } # Matches!!!
}

Under the new scheme, given($array_ref) won’t be particularly
meaningful, will it?

So should given(@​a) continue to turn automagically into given(\@​a)?

Oh, so it's not just when(), but given also has weird syntax special
cases? )​:

In my opinion, as long as we're fixing everything else, given(@​a) should
just be interpreted as given(scalar(@​a)).

-doy

From @cpansprout

On Tue Sep 11 22​:37​:30 2012, doy@​tozt.net wrote​:

On Tue, Sep 11, 2012 at 10​:34​:14PM -0700, Father Chrysostomos via RT
wrote​:

On Thu Jul 22 09​:14​:47 2010, ikegami@​adaelis.com wrote​:

given (@​a) {
when (/abc/ ) { say '/abc/'; continue; } # Doesn't match!!!
when (qr/abc/) { say 'qr/abc/'; continue; } # Matches
when (/ARRAY/) { say '/ARRAY/'; continue; } # Matches!!!
}

Under the new scheme, given($array_ref) won’t be particularly
meaningful, will it?

So should given(@​a) continue to turn automagically into given(\@​a)?

Oh, so it's not just when(), but given also has weird syntax special
cases? )​:

In my opinion, as long as we're fixing everything else, given(@​a) should
just be interpreted as given(scalar(@​a)).

This is probably getting off-topic for this ticket, but newWHENOP is
part of the API, yet its parameter list is not sufficient to distinguish
when() from when{}, and its unused on CPAN.

Is this something that can change? (I.e., if we are going to break Perl
code [probably just one module], is it OK to break XS at the same time
[probably none].)

--

Father Chrysostomos