Re: defined &{ $pkg . '::foo' } vs. $pkg->can( 'foo' )

$ perl -w
sub foo;
sub AUTOLOAD { print "called $AUTOLOAD" }
print "is foo defined? ",0+defined &foo, " does foo exist? ", 0+exists
+ &foo, "\n";
foo();
__END__
is foo defined? 0 does foo exist? 1
called main::foo
[download]

You almost always want to use exists &subname rather than defined &subname; there's no advantage in excluding declared-but-not-defined subs.

Comment on Re: defined &{ $pkg . '::foo' } vs. $pkg->can( 'foo' ) Download Code

Replies are listed 'Best First'.
Re^2: defined &{ $pkg . '::foo' } vs. $pkg->can( 'foo' ) by tlm (Prior) on Jul 15, 2005 at 12:56 UTC
You almost always want to use exists &subname rather than defined &subname; there's no advantage in excluding declared-but-not-defined subs. Hmmm... I don't see how including declared-but-not-defined subs could be a good idea either for the particular application I had in mind or for the one I cited. the lowliest monk	[reply]
Re^3: defined &{ $pkg . '::foo' } vs. $pkg->can( 'foo' ) by ysth (Canon) on Jul 15, 2005 at 20:26 UTC
I don't see why. Pre-declaring subs is the responsible way to use AUTOLOAD. Why would you want to disallow it in your delegatees? Anyway, this qualifies as a difference between ->can and defined&.	[reply]
Re^4: defined &{ $pkg . '::foo' } vs. $pkg->can( 'foo' ) by tlm (Prior) on Jul 15, 2005 at 20:48 UTC
Pre-declaring subs is the responsible way to use AUTOLOAD. I wasn't aware of this convention. Good to know. Thanks. the lowliest monk	[reply]