#!/usr/bin/perl -w

use strict;


sub map_recursive {
    my ($structure, $predicate) = @_;
    my @result;
    if (UNIVERSAL::isa($structure, 'ARRAY')) {
        for (@{$structure}) {
            push @result, map_recursive($_, 
                                        $predicate);
        }
    } elsif (UNIVERSAL::isa($structure, 'HASH')) {
        for (keys %{$structure}) {
            push @result, map_recursive($structure->{$_}, 
                                        $predicate);
        }
    } else {
        push @result, $predicate->($structure);
    }
    return @result;
}


my $scalar = 2;
my @list = (1, 3, 8, 10);
my %hash = (a => 1, b => 2, c => 3);

my $oddp = sub { (((shift) % 2) == 1) ? 1 : 0 };


print "#1: ", join(",", map_recursive($scalar, $oddp)), "\n";
print "#1: ", join(",", map_recursive(\@list, $oddp)), "\n";
print "#1: ", join(",", map_recursive(\%hash, $oddp)), "\n";