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Postings from April 2007
On 4/3/07, Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:
> On 4/2/07, Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:
I've also found that length() is magical with numbered captures:
use re::engine::Plugin (
exec => sub {
my ($re, $sv) = @_;
$re->captures( [ "ook" ] );
1: # successful match
}
);
"str" =~ /pattern/;
warn $1; # "ook"
warn length($1); # 0
This is because Perl_magic_len gets called for $1, that function
checks rx->offs which doesn't do what's expected when $1 isn't really
stored there.
I think the best way to solve this is to have tie-like callbacks for
named captures in the regexp_engine struct (names modelled after
Tie::Scalar):
FETCH(pTHX_ const REGEXP * const rx, I32 paren, SV* usesv);
STORE(pTHX_ const REGEXP * const rx, I32 paren, SV* usesv, SV* sv);
LENGTH(pTHX_ const REGEXP * const rx, const char * const mg_ptr);
This would allow for fast length() by having the perl engine do what
it does currently in mg.c in some engine-specific function, allow for
$1 = "foo" via STORE which the perl engine would implement by calling
Perl_croak().
I'm not really sure what datatypes to use, mg_ptr which is used in
Perl_magic_len can be $1 .. $9, $&, $`, $' and also $+ and $^N.
Similarly the engine would implement a Tie::Hash-like interface for %+ and %-.
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