Perl6::Rules oddity?

supergiantrobot has asked for the wisdom of the Perl Monks concerning the following question:

P6R is fun, but a little maddening, too. I see that I am going to have to learn Perl 6 more! Anyway, I am stumped why $0 doesn't contain three hash keys in the code below. The input looks like this:

hEAD: one

DeCK: two

By: three

four I<five six>

BiO: seven
[download]

Shouldn't $0 have hash keys foo and deck?

use strict;
use Perl6::Rules -debug;

rule head    :i { HEAD <COLON> }
rule deck    :i { DECK <COLON> }
rule byline :i { BY <COLON> }
rule bio     :i { BIO <COLON> }
rule body     :w { <para> [<blankline> <para>]* }
rule para     :w { <line>+ }
rule figure :i { }
rule line     { <word>+? \v }
rule word    { <italics> | <[\S+]>? }
rule italics :w { I <LANGLE> ([<word>|\v]+) <RANGLE> }
rule blankline    { ^^$$ }
rule COLON            { \: }

"abcd" =~ m/a  $?foo:=(..)  d/;
print "yes" if ($0->{foo} eq "bc");
$0->dump();

#
# get all input
my @line = <>; my $line = join('', @line);

if ($line =~
    m:words/
        <head> $?foo:=(<line>)
        <deck> $?deck:=(<line>)    
        [<byline> $?by:=(<line>)]?    
    /)
{
    $0->dump();
}
[download]

Comment on Perl6::Rules oddity? Select or Download Code

Replies are listed 'Best First'.
Re: Perl6::Rules oddity? by TheDamian (Vicar) on May 03, 2004 at 22:22 UTC
Definitely a bug. I'm working on a fix (in my CFT). Damian	[reply]
Re: Re: Perl6::Rules oddity? by supergiantrobot (Acolyte) on May 04, 2004 at 04:06 UTC
Thanks for the reply, DC. Do I get some camel poo as a token of my obfuscation? :-)	[reply]
Re: Re: Re: Perl6::Rules oddity? by TheDamian (Vicar) on May 04, 2004 at 21:10 UTC
Sorry, we reserve camel dung for our Special Friends who ask questions that are already answered in TFM. `;-)`	[reply]
Re: Perl6::Rules oddity? by hossman (Prior) on May 04, 2004 at 06:32 UTC
Ya know, as someone still running 5.6, I've never really taken a good look at Perl6::Rules. It never occured to me that the Damain's perl5 implementation would acctually set $0. That must make for some interesting "ps" output while doing lots of parsing.	[reply]
Re: Re: Perl6::Rules oddity? by broquaint (Abbot) on May 04, 2004 at 16:26 UTC
While `$0` is used to neat effect its associated perl5 `MAGIC` is not used, and I quoth from the source `# Turn off special $0 magic 0 = \ my $zero;` [download] After that `$0` will loose it's magical behaviour e.g `shell> perl -MDevel::Peek - Dump $0; 0 = \ my $zero; Dump $0; ^D SV = PVMG(0x99900b0) at 0x999410c REFCNT = 1 FLAGS = (GMG,SMG,pPOK) IV = 0 NV = 0 PV = 0x99950e8 "-"\0 CUR = 1 LEN = 2 MAGIC = 0x99950f8 MG_VIRTUAL = &PL_vtbl_sv MG_TYPE = PERL_MAGIC_sv(\0) MG_OBJ = 0x9994100 MG_LEN = 1 MG_PTR = 0x9995118 "0" SV = NULL(0x0) at 0x9997828 REFCNT = 2 FLAGS = (PADBUSY,PADMY)` [download] Although leaving `$0` scrubbing out could certainly lead to some interesting debugging facilities in conjunction with `top` ;) HTH `_________ broquaint`	[reply] [d/l] [select]