#!/usr/bin/perl

use strict;
use warnings;

my $beholder_default = 'beholder';
my $param = get_param();

my %monster_lookup = (
  'beholder' => {
    book => 'Monstrous Manual',
    beholder => 1,
    page => 21,
  },
  'death kiss' => {
    book => 'Monstrous Manual',
    beholder => 0,
    page => 21,
  },
);

# this saves duplicating data in your code
my @monsters = keys %monster_lookup;


my $monster;
if ($param){
  $monster = $beholder_default;
}
else{
  my $rand = int rand @monsters;
  $monster = $monsters[$rand];
}

my $book     = $monster_lookup{$monster}{book};
my $page     = $monster_lookup{$monster}{page};
my $beholder = $monster_lookup{$monster}{beholder};

if (not $beholder){
  print "$monster ";
}
print "beholder ($book, pg $page)\n";

sub get_param {
  # get your input from somewhere
  my $param = 0;
  return $param;
}
[download]

Here is the hash as I would like it with the "default" book as a scalar, and used in the hash. I hope that works.

my $MM = "Monstrous Manual"
my %monster_lookup = (
'beholder' => {
  book => $MM,
  beholder => 1,
  page => 21,
},
'death kiss' => {
  book => $MM,
  beholder => 0,
  page => 21,
},
'eye of the deep' => {
  book => $MM,
  beholder => 0,
  page => 21,
},
'gauth' => {
  book => $MM,
  beholder => 0,
  page => 21,
},
'spectator' => {
  book => $MM,
  beholder => 0,
  page => 21,
},
'undead' => {
  book => $MM,
  beholder => 0,
  page => 21,
},
'hive mother' => {
  book => $MM,
  beholder => 0,
  page => 25,
},
'director' => {
  book => $MM,
  beholder => 0,
  page => 25,
},
'examiner' => {
  book => $MM,
  beholder => 0,
  page => 25,
},
'lensman' => {
  book => $MM,
  beholder => 0,
  page => 25,
},
'overseer' => {
  book => $MM,
  beholder => 0,
  page => 25,
},
'watcher' => {
  book => $MM,
  beholder => 0,
  page => 25,
},
);
[download]

Would Perl be okay with the following?

my $MM = "Monstrous Manual"
my %monster_lookup = (
'beholder' => {book => $MM,beholder => 1,page => 21,},
'death kiss' => {book => $MM,beholder => 0,page => 21,},
'eye of the deep' => {book => $MM,beholder => 0,page => 21,},
'gauth' => {book => $MM,beholder => 0,page => 21,},
'spectator' => {book => $MM,beholder => 0,page => 21,},
'undead' => {book => $MM,beholder => 0,page => 21,},
'hive mother' => {book => $MM,beholder => 0,page => 25,},
'director' => {book => $MM,beholder => 0,page => 25,},
'examiner' => {book => $MM,beholder => 0,page => 25,},
'lensman' => {book => $MM,beholder => 0,page => 25,},
'overseer' => {book => $MM,beholder => 0,page => 25,},
'watcher' => {book => $MM,beholder => 0,page => 25,},
);
[download]

What I really want with the book key is that if it is empty, then the default book, else what is in the book in the key.

The argument between using package or lexical variables can continue at a later time.

Corrections:

• quoting
• hash item without keys.
• copy/paste errors

Update

• 2nd bit of code without the whitespace

If you are obsessed with saving space, you could do something like:

# In case you want to access the array mnemonically.
# Depending on your version of perl, you might need to
# declare one constant at a time.
use constant {
  BOOK => 0, BEHOLDER => 1, PAGE => 2
};

my $MM = "Monstrous Manual";

my %monster_lookup = (
'beholder' => [$MM, 1, 21],
'death kiss' => [$MM, 0, 21],
'eye of the deep' => [$MM, 0, 21],
#etc...
);

my $monster_type = 'beholder';
my $monster = $monster_lookup{$monster_type};

printf "Monster: %s Book: %s Beholder: %s Page: %s\n", $monster_type, 
+@$monster;

# E.g. accessing one attribute at a time
print "$monster->[BOOK]\n";
[download]