Not quite an answer, but I wonder what problem you wish to solve? Generally, when my code starts to get complex and I have to devise something really tricky to get around it, I find that I need to revisit my design. Most of the time, in such a situation, it's a design flaw on my part (of course, it could just be that I'm a rotten programmer, too :).

Not to say that you have poorly designed code. I wouldn't know. I realize that you may simply be asking this for informational purposes.

Cheers,
Ovid

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heh. for some definitions of "poorly".

Problem:
Trying to allow lazy maintenance of multiple interface widgets, frinstance Receipt::DoubleA, Receipt::TextOnly, Receipt::BannerAds, etc

at a level above the widgets, we have an AUTOLOAD that allows us to call $ui->Receipt->build(%args), and it will use the Receipt parent class or choose the right subclass based on external criteria.

The problem is, for example, that we might have a Text subclass under Receipt, but not have one under Error.

In that case we could

• 1) mandate the creation of an "empty" subclass for every widget for each new interface, with at minimum an @ISA statement
• 2) descend into some inelegant evalling or -e testing at some level (perhaps in the parent widget class), or
• 3) see if there might be a way to check from upstream if in fact there was a Text interface for a particular widget before trying to AUTOLOAD it.
• 4) accept new and novel suggestions from perlmonks, et al.

  Ideally, without keeping a separate registry hash of available interfaces, of course ;)

  As you noted, perhaps too tricky. The extenuating circumstances of how we got here are lengthy and boring.

  {::} =D------an (sometimes the cord just doesn't quite reach)

Would UNIVERSAL::can help here at all? And perhaps understanding that when you define AUTOLOAD, you should also override can?

-- Randal L. Schwartz, Perl hacker

But I agree with ovid. If this was the answer, you've probably asked the wrong question. Back up a step.

-- Randal L. Schwartz, Perl hacker

-- Randal L. Schwartz, Perl hacker