use Perl

• Recursive closures (Score:2)

  by TorgoX (1933)

  I think I use a bunch of recursive closures in HTML::Element. The trick is that (unless you use a Y-operator, which is fiendish) once you define this:

  my $x; $x = sub { ... $x->(...) ... };

  ...you've just defined a circular data structure. So once you're finished with the whole excursion of calling $x, you have to undef $x or the sub-object doesn't get destroyed -- at least last I checked.
  • Re:Recursive closures (Score:1)

    by koschei (147)

    Do you happen to have an example of the use of one of these fiendish Y operators in Perl? (If you don't, don't feel compelled to write one if you don't want to, I'm mostly only curious for curiosity's sake.)

    --
      ---ict / Spoon
    • Y Operator in Perl (Score:2)

      by TorgoX (1933) <sburkeNO@SPAMcpan.org> on 2002.05.25 18:26 (#8839) Homepage Journal

      http://www.speech.cs.cmu.edu/~sburke/pub/y_operator.pl [cmu.edu]

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      • Re: Y Operator in Perl (Score:1)

        by robin (1821)

        That reminds me of a staggering bit of obfuscated Haskell programming [willamette.edu].