If you use the pseudo-two-dimensional index (using a comma):
 $hash{'a', 'b'}

[download]
you only get a single key, that is, "a\034b" (unless you change $; ). This is like AWK's simulation of multi-dimensional arrays/hashes, right down to the use of SUBSEP ("\034") as a delimiter. Look at the following with Data::Dumper (I changed $; so you could see it):
use strict;
use Tie::Hash;
package Tie::HashNKeys;
use base 'Tie::StdHash';

sub TIEHASH {
my $class = shift;
bless {}, $class;
}

sub STORE {
 $_[0]->{ join $;, sort split /$;/, $_[1] } = $_[2];
}

sub FETCH {
$_[0]->{ join $;, sort split /$;/, $_[1] };
}

package main;
use Data::Dumper;

$; = '~'; # so it can be seen
tie my %hash, 'Tie::HashNKeys';
$hash{'csUsers','csGroups'} = 'foo';
print $hash{'csGroups','csUsers'};   ## prints 'foo'
print Dumper(\%hash);

[download]

In reply to Re: Tied Hash to emulate double-key hash only accepts one key by bikeNomad
in thread Tied Hash to emulate double-key hash only accepts one key by AidanLee

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.