in reply to Removing CODE slot in typeglob / Reversing "use subs ...;"

I've done no real testing (my food is ready), but is this the effect you are looking for? 

#! perl -slw
use strict;
use 5.010;

sub FOO () { 'foo' }
BEGIN { undef $::{FOO} }
say defined &FOO ? 'subroutine defined' : 'subroutine undef';
say eval 'FOO if $false; 1' ? 'FOO allowed' : 'FOO not allowed';

__END__
C:\test>660264.p10
subroutine undef
FOO not allowed

[download]
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

Replies are listed 'Best First'.
Re^2: Removing CODE slot in typeglob / Reversing "use subs ...;"
by lodin (Hermit) on Jan 03, 2008 at 18:21 UTC

    Beware of the $false in there. Your eval fails because you turned on stricture, but even with my $false; it fails, so that's good. Unfortunately it works too well.

    undef $::{FOO} is the same as undef *FOO and that undefined the whole typeglob. 

    our $FOO = 'foo';
undef $::{FOO};
print defined $FOO ? 'defined' : 'undef';

__END__
undef

    [download]
    I only want to remove the CODE slot in the typeglob.

    lodin

[reply]
[d/l]
[select]

      Again, I'm only adressing the symptoms rather than thinking things through, but how's this? 

      #! perl -slw
use strict;
use 5.010;

our $FOO = 'fred';
sub FOO () { 'foo' }
BEGIN { undef $::{FOO}{CODE} }
say defined &FOO ? 'subroutine defined' : 'subroutine undef';
say eval 'FOO if $false; 1' ? 'FOO allowed' : 'FOO not allowed';
print $FOO;

__END__
C:\test>660264.p10
subroutine defined
FOO not allowed
fred

      [download]
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

        It's the $false playing tricks again.

        $::{FOO} is the typeglob for FOO in main, and a typeglob can be dereferenced as a hash, and that's exactly what $::{FOO}{CODE} does. It becomes more clear if you add the arrow: $::{FOO}->{CODE}. The reason it works without the arrow is that $::{FOO} is an element of the %:: hash, so it's no different than $foo{bar}{baz}. 

        use 5.010;

our %FOO = (CODE => 'hash value');
say $::{FOO}{CODE};

__END__
hash value

        [download]

        lodin

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom