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NOTE: use Perl; is on undef hiatus. You can read content, but you can't post it. More info will be forthcoming forthcomingly.

All the Perl that's Practical to Extract and Report

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  • So it can serialize closures without losing information?
    • Yep. Eg:

      D:\Development>perl -MDDS -e"my $closure=do{ my $x=100; sub { $x++ } }; Dump $closure"

      my ($x);
      $x = 100;
      $CODE1 = sub {
                            $x++;
                        };
      • The following code crashes.
        #! /usr/bin/perl
        use strict;
        use Data::Dump::Streamer;

        Dump [
          map {
            my $x;
            my $x_eclipse_1;
            sub {$x}, sub {$x_eclipse_1};
          } 1, 2
        ];
        I thought about trying to solve this with intelligent mangling, but there is always a boundary case. For instance if you mangle anything with $x_eclipse_1 in some way (eg make it $x__eclipse_1), what if there is a global variable $x_eclipse_1? Now you've changed semantics or else get a crash.

        After some thinking, the only strategy that looks like it would work perfectly is to go to a nested data structure in the event of collisions. You could do that like this. Suppose that you had multiple closures pointed at $foo. Then make $foo an anonymous array of scalars and make the closures each point at $foo->[$i] where $i is an index. In the case of @foo you can make it @{$foo[$i]} instead. In the case of %foo you can make it %{$foo{$i}}. In each case the eclipsing is done without accessing any other variable name that might also be accessed.

        • The following code crashes.

          Shoot. Yep. It does. And it highlights what I forgot to document: the subs being dumped shouldn't mix the use of dynamics and lexicals with the same name, and that its is unwise to use variables matching /_eclipse_\d+$/. (Which personally I think is not such a terrible restriction, albeit not at all ideal.)

          Dealing with the former is actually very tricky, and probably wont ever be solved properly. A good example is

          my $a=sub { $a++ };

          The second issue regarding eclipsed