gistfile1.txt

#!/usr/bin/perl
## In sort method, generated sub routine can't access to the lexical variables
## of outer scope...

use strict;
use warnings;

sub my_sort ($$) {
    my ( $a, $b ) = @_;
    my $foo = 1;
    my $code = sub {
        return $foo;
    };
    my $res = $code->() || 0;
    print STDERR ( $foo == $res ? "Match\n" : "Not Match\n" );
    return $a <=> $b;
}

print STDERR "Just call it\n";
my_sort(1,2); # prints "Match"

print STDERR "Called from sort method\n";
my @sorted = sort my_sort (1,2); # but this prints "Not Match"...