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Re: How to de-reference a coderef? (B tricks)

by ysth (Canon)
on Dec 10, 2004 at 10:35 UTC ( [id://413799]=note: print w/replies, xml ) Need Help??


in reply to How to de-reference a coderef?

Unlike e.g. array refs, every code ref has a backreference to its glob (so that when you call it, caller can know the sub name). This is fairly easily accessible with the B module (which provides introspection facilities for perl thingies): 
use B;
sub coderef2name {
   eval {
      my $obj = B::svref_2object( shift() );
      $obj->GV->STASH->NAME . "::" . $obj->GV->NAME;
   } || undef;
}

[download]
Returns something like pkgname::__ANON__ for anonymous subs, or undef if something goes wrong (like being passed an array ref instead of a code ref).

Updated to use GV->STASH->NAME, not STASH->NAME. Thanks, betterworld

Replies are listed 'Best First'.
Re^2: How to de-reference a coderef? (B tricks)
by Anonymous Monk on Aug 24, 2011 at 01:14 UTC
    How do you do this in XS? Given a CV how do you get the name for the corresponding named sub?
[reply]
      use strict;
use warnings;
use feature qw( say );

use Inline C => <<'__EOI__';

SV* coderef2name(CV* cv) {
   const GV *   const gv        = CvGV(cv);
   const HV *   const stash     = GvSTASH(gv);
   const char * const pkg_name  = HvNAME(stash);
   const char * const func_name = GvNAME(gv);
   SV *         const fqn       = newSVpvn("", 0);

   sv_catpv(fqn, pkg_name);
   sv_catpv(fqn, "::");
   sv_catpv(fqn, func_name);

   return fqn;  // Mortalised by Inline
}

__EOI__

sub f {}

say coderef2name(\&f);

      [download]
[reply]
[d/l]
      You call coderef2name from XS, that is how you do it
[reply]

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