#!/usr/bin/perl -w

use strict;
use warnings;

# Set empty strings/arrays
my $typed_command = my $cmd_verb = my $cmd_noun = my $action = "";
my @cmd_list = ();

# Define subroutines
sub misunderstood {print "I don't understand `@cmd_list'\n";}
sub go_north {print "You go north\n";}
sub go_south {print "You go south\n";}
sub go_west {print "You go west\n";}
sub go_east {print "You go east\n";}
sub get {print "You take the $cmd_noun\n";}
sub jump {print "Boing! Boing!\n";}
sub quit {print "See you later.\n"; exit;}

# Declare valid commands hash table
# Pair up the commands with the subroutines that will execute them.
# The verb is used as a key in the hash table for quick selection.
# This will avoid a whole string of if statements later and keep the
# definition near the top of the program for easy editing later.
# Don't forget to include synonyms!

my %valid_commands = (
    'north',   \&go_north,      'n',       \&go_north,
    'south',   \&go_south,      's',       \&go_south,
    'west',    \&go_west,       'w',       \&go_west,
    'east',    \&go_east,       'e',       \&go_east,
    'get',     \&get,           'take',    \&get,
    'quit',    \&quit,          'jump',    \&jump,
);

# Main loop

print "What now?>";
while (defined($typed_command = <STDIN>)) {
    @cmd_list = split " ", lc($typed_command);
    $cmd_verb = $cmd_list[0];
    $cmd_noun = $cmd_list[1];
    if (exists($valid_commands{$cmd_verb})) {
        $action = $valid_commands{$cmd_verb};
        &$action($cmd_noun);
    }
    else {
        &misunderstood(@cmd_list);
    }
    print "What now?>";
}