What about a base class? Do such classes always have a declared  @ISA that is empty?

Actually I don't understand the discussion anymore, if the OP was willing to inspect a class the natural solution would be ->can.

If he wasn't inspecting a class ->can would do the job, too.

Are there pathological cases where an approach might break?

Of course, this is Perl, with high flexibility to bend internals.

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}

No, that's not true.

If they're trying to resolve a method, then ->can is correct.

If they're trying to resolve a sub, then ->can can fail

The OP is looking for a sub.

So it is as I said. You're suggesting that we use

my $sub =
   @{ get_array_by_name($pkg, 'ISA') }
      ? get_sub_by_name($pkg, $name)
      : $pkg->can($name);
[download]

my $sub = get_sub_by_name($pkg, $name);
[download]

That's ludicrous.

> You're suggesting that we use

>  my $sub = @{ get_array_by_name($pkg, 'ISA') } ? get_sub_by_name($pkg, $name) : $pkg->can($name);

No, I don't!

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}

uh, then feel free to clarify why you meant by "one can easily check @ISA".

> get_sub_by_name

which get_sub_by_name?

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}

He probably means something hypothetical...

I was actually thinking about this seriously, and I would likely do something as:

sub get_sub_by_name {
    my ($pkg, $name) = @_ ;
    no strict 'refs' ;
    if ( exists ${$pkg . '::'}{$name} ) {
        if ( ref ${$pkg . '::'}{$name} eq 'CODE' ) {
            return *{$pkg . '::' . $name} ;
        }
    } ;
}
[download]

Maybe it can be written more pretty, and I don't know if any odd-cases are trapped (e.g. what about __ANON__)

edit: Comes to think of it, maybe the line 'exists' is not even needed?

Some code that gets a reference to the sub by name. What that code is doesn't matter, though it could be as simple as \&{ $pkg . '::' . $name }.