#/usr/bin/perl -w
use strict;
use constant {
  Undefined => 0,
  Page => 1,
  Index => 2,
};

my %map = (
  Page => 'mypage',
  Index => 'myindex',
);

foreach my $k (keys %map) {
  printf "key=%s, val=%s\n", $k, $map{$k};
}