in reply to Creating stub methods

update: Remember my vars::i, how about a subs::i, which would go something like 
=head1 NAME

subs - Perl pragma to declare sub names and initialize them?

=head1 SYNOPSIS

   use subs::i start_html => \&AUTOLOAD;

=cut

package subs::i;
sub import {
    my $callpack = caller;
    my $pack = shift;
    my %imports = @_;
    foreach $sym (keys %imports) {
    *{"${callpack}::$sym"} = $imports{$sym};
    }
};

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Re: Re: Creating stub methods
by Ovid (Cardinal) on Dec 29, 2003 at 18:18 UTC

    Actually, I think the "use subs" declaration solves the problem I was looking at, though I kind of like your "subs::i" idea. And you're right that it would be nice if CGI.pm provided a "can" method, but so many people use UNIVERSAL::can() directly that I think simply predeclaring the subs would be easier.

    Update: What I think is really nifty about the subs pragma is the line:

    *{"${callpack}::$sym"} = \&{"${callpack}::$sym"};

    We create the slot in the typeglob, but assign an undefined value. $module->can($method) works because we have the slot, but AUTOLOAD still gets called because there is no actual subroutine or method there. Nifty!

    Cheers,
    Ovid

    New address of my CGI Course.

[reply]
[d/l]
      In fact it's not undefined in the full sense of the word. If you take a reference to a named sub which isn't yet defined, that reference magically becomes defined and valid as soon as that sub is defined. Observe: 
      $_ = \&x;
*x = sub { print "Oh my\n" };
$_->();

      [download]
      This does print "Oh my". Perl is devious like that.

      Makeshifts last the longest.

[reply]
[d/l]

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