Again a fun quiz! I remember reading this tutorial too.
This is my solution, which uses Highline (version 1.* recommended). My
approach was far more rewrite-based. Unfortunately, I didn't come up
with a nice game-action "macro".
The user interface is the same as the Lisp program's, but omitting the
parens. BTW, why does Highline lose when EOF is encountered? I really
miss the Ctrl-D...
Anyway, I noticed one could cheat in my game:
take bucket
instance_variable_set @bucket_filled foobar
splash bucket wizard
Voila. 
Markus
···
======
#! /usr/bin/env ruby
require 'highline/import'
require 'set'
# This is a kind of room, including a garden.
class Room
def initialize(description, *items)
@description = description
@directions = Hash.new
@direction_gateways = Hash.new
@inventory = Set.new(items)
end
def look
puts @description
@direction_gateways.each do |dir, gateway|
puts "There is a #{gateway} going #{dir} from here."
end
@inventory.each do |item|
puts "You see a #{item} on the floor."
end
end
def define_direction(dir, gateway, where)
@directions[dir] = where
@direction_gateways[dir] = gateway
end
# returns the place a direction leads to
def get_direction(dir)
@directions[dir]
end
def have?(item)
@inventory.include? item
end
def drop(item)
@inventory.add item
end
def take(item)
@inventory.delete item
return item
end
end
# Define the rooms with items in them.
$livingroom = Room.new("You are in the living-room of a wizard's
house.\n" +
"There is a wizard snoring loudly on the couch.", :bucket)
$attic = Room.new("You are in the attic of the abandoned house.\n" +
"There is a giant welding torch in the corner.")
$garden = Room.new("You are in a beautiful garden.\n" +
"There is a well in front of you.", :chain, :frog)
# Connect the rooms.
$livingroom.define_direction :west, :door, $garden
$livingroom.define_direction :upstairs, :stairway, $attic
$attic.define_direction :downstairs, :stairway, $livingroom
$garden.define_direction :east, :door, $livingroom
# This is the guy you control.
class Apprentice
# texts that are shown at The End
ENDGAME_WIN =
"The wizard awakens from his slumber and greets you\n" +
"warmly. He hands you the magic low-carb donut -\n" +
"You win! The End."
ENDGAME_LOSE =
"The wizard awakens and sees that you stole his frog.\n" +
"He is so upset he banishes you to the netherworlds -\n" +
"You lose! The End."
ENDGAME_EXIT =
"The wizard awakens, puling disappointedly,\n" +
" Premature disassociation is the root\n" +
" Of all eval."
def initialize
@location = $livingroom
@inventory = Set.new([:"whiskey-bottle"])
@chain_welded = false
@bucket_filled = false
end
# *** Commands for exploring the house ***
def exit
# show the wizard's wisdom
puts ENDGAME_EXIT
# if this was plain "exit", we had infinite recursion...
Kernel.exit
end
alias quit exit
def look
@location.look
end
def walk(dir)
if @location.get_direction(dir)
@location = @location.get_direction(dir)
@location.look
elsif @location == $garden and dir.to_s.hash == -781591621
# well, how do you get here?
puts 'You see a maze of twisty little passages,'
puts 'all alike. But you can\'t go there.'
else
puts "You can't go #{dir}."
end
end
alias go walk
# *** Commands for handling items ***
# note: have? does not print anything
def have?(item)
@inventory.include? item
end
def have(item)
puts have?(item)
end
def drop(item)
if have? item
@location.drop item
@inventory.delete item
puts "You are no longer carrying the #{item}."
else
puts "You do not have that."
end
end
def take(item)
if @location.have? item
@inventory.add @location.take(item)
puts "You are now carrying the #{item}."
else
puts "I see no #{item} here."
end
end
alias pickup take
def inventory
if @inventory.empty?
puts 'You are carrying no items.'
else
inventory_text = @inventory.to_a.join(', ')
puts "You are carrying: #{inventory_text}"
if have? :bucket and @chain_welded
puts 'The chain is welded to the bucket.'
end
if have? :bucket and @bucket_filled
puts 'The bucket is filled with water.'
end
end
end
# *** Game actions ***
def weld(subject, object)
if @location == $attic and have? :chain and have? :bucket and
subject == :chain and object == :bucket
@inventory.delete :chain
@chain_welded = true
puts 'The chain is now securely welded to the bucket.'
else
puts 'You cannot weld like that.'
end
end
def dunk(subject, object)
if @location == $garden and have? :bucket and
subject == :bucket and object == :well
if @bucket_filled
puts 'The bucket is already filled.'
elsif @chain_welded
@bucket_filled = true
puts 'The bucket is now full of water.'
else
puts 'The water level is too low to reach.'
end
else
puts 'You cannot dunk like that.'
end
end
def splash(subject, object)
if @location == $livingroom and have? :bucket and
subject == :bucket and object == :wizard
if not @bucket_filled
puts 'The bucket has nothing in it.'
elsif have? :frog
puts ENDGAME_LOSE
Kernel.exit
else
puts ENDGAME_WIN
Kernel.exit
end
else
puts 'You cannot splash like that.'
end
end
end
# Create the apprentice.
$apprentice = Apprentice.new
$apprentice.look
# Provide a user interface.
loop do
# read a line
command = ask('>> ') do |question|
# try to use Readline (only Highline 1.0.0 and above)
if question.respond_to? :readline=
question.readline = true
end
end
# run the command
begin
commandwords = command.split.map {|x| x.downcase.to_sym}
$apprentice.send *commandwords unless commandwords.empty?
rescue ArgumentError, NoMethodError
puts 'I do not understand.'
end
end
