#!/usr/bin/perl -w
use strict;
use warnings;

my %xxx = (a=>5, b=>10, c=> {ca=>9, cb=>10});
my @yyy = ( [0, 1], {red=>2, blue=>3} );
my $aa = 5; my $bb=\%xxx; my $cc=\@yyy;
print "aa=", thing_to_string($aa), "\n";
print "bb=", thing_to_string($bb), "\n";
print "cc=", thing_to_string($cc), "\n";

sub thing_to_string {
    my $t = shift;
    return '???UNDEF???' if !defined $t;
    if (ref $t eq '') {
        # It's a scalar, return it's value
        return $t;
    }
    elsif (ref $t eq 'ARRAY') {
        # It's an array, turn all the elements into strings,
        # separate them with commas, and wrap 'em in '(' and ')'
        return "(".join(", ", map { thing_to_string($_) } @$t ).")";
    }
    elsif (ref $t eq 'HASH') {
        # It's a hash, turn all the elements into "key:value",
        # separate them with commas, and wrap 'em in '{' and '}'
        return "{".join(", ", map { $_."=>".thing_to_string($$t{$_}) }
                              sort keys %$t)."}";
    }
    # some other thing...
    return "...other...";
}

##</code><code>##

[10:41:17] ~
$ perl -e '$a=5; print ref($a)'

[10:41:29] ~
$

##</code><code>##

[10:41:29] ~
$ perl -e '$a=5; print ref(\$a)'
SCALAR
[10:43:19] ~
$ perl -e '@a=(1,2); print ref(\@a)'
ARRAY
[10:43:23] ~
$ perl -e '%a=(1=>0,2=>0); print ref(\%a)'
HASH
[10:43:26] ~
$