[SOLUTION] Lisp Game (#49)

M

Markus Koenig

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:

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
 
G

Gregory Brown

Markus said:
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...

Hmm... not exactly sure why this doesn't work. I'll try to dig through
HighLine and figure this out if I get some time this week, if James
doesn't beat me to the punch, that is :)
 
M

Markus Koenig

Gregory said:
Hmm... not exactly sure why this doesn't work. I'll try to dig through
HighLine and figure this out if I get some time this week, if James
doesn't beat me to the punch, that is :)

This is what I get from HighLine 1.0.1:

[...]
/usr/lib/ruby/site_ruby/1.8/highline/question.rb:362:in `send':
undefined method `strip' for nil:NilClass (NoMethodError)
from /usr/lib/ruby/site_ruby/1.8/highline/question.rb:362:in `remove_whitespace'
from /usr/lib/ruby/site_ruby/1.8/highline.rb:527:in `get_line'
from /usr/lib/ruby/site_ruby/1.8/highline.rb:545:in `get_response'
from /usr/lib/ruby/site_ruby/1.8/highline.rb:155:in `ask'
from lispgame.rb:221
from lispgame.rb:219:in `loop'
from lispgame.rb:219

In question.rb:362 the result of readline (highline.rb:528) or gets
(highline.rb:533) is stripped. I guess the cleanest thing to do is just
to raise EOFError if any of these methods returns nil.

This wasn't that hard :)

Regards,
Markus
 
J

James Edward Gray II

Gregory Brown wrote:

Markus Koenig wrote:



Hmm... not exactly sure why this doesn't work. I'll try to dig
through
HighLine and figure this out if I get some time this week, if James
doesn't beat me to the punch, that is :)

This is what I get from HighLine 1.0.1:

[...]
/usr/lib/ruby/site_ruby/1.8/highline/question.rb:362:in `send':
undefined method `strip' for nil:NilClass (NoMethodError)
from /usr/lib/ruby/site_ruby/1.8/highline/question.rb:
362:in `remove_whitespace'
from /usr/lib/ruby/site_ruby/1.8/highline.rb:527:in `get_line'
from /usr/lib/ruby/site_ruby/1.8/highline.rb:545:in
`get_response'
from /usr/lib/ruby/site_ruby/1.8/highline.rb:155:in `ask'
from lispgame.rb:221
from lispgame.rb:219:in `loop'
from lispgame.rb:219

In question.rb:362 the result of readline (highline.rb:528) or gets
(highline.rb:533) is stripped. I guess the cleanest thing to do is
just
to raise EOFError if any of these methods returns nil.

Hello Markus.

I'm very interested in understanding this problem and fixing it
correctly. Could you please show a trivial HighLine script and how
you are trying to use it, so I can wrap my head around this?

Thanks.

James Edward Gray II
 
M

Markus Koenig

Hello James,

I really appreciate your and Greg's work. It's nice to see what can
evolve from a simple quiz idea. :)
I'm very interested in understanding this problem and fixing it
correctly. Could you please show a trivial HighLine script and how
you are trying to use it, so I can wrap my head around this?

I think HighLine's methods should either raise EOFError or return nil
if EOF is reached, but I'm not sure which one would be nicer. Maybe a
hybrid approach, like IO#gets and IO#readline?

The trivial script, if the methods return nil:

require 'highline/import'
loop do
name = ask("What's your name?")
if response.nil? or response == 'exit'
puts 'Goodbye, dear friend.'
exit
else
puts "Hello, #{name}!"
end
end

I expect this program to behave like most Unix shells - quietly quit
when one presses Ctrl-D (EOF). But this would print a stack trace, as
shown earlier.

Thanks,
Markus
 
J

James Edward Gray II

Hello James,

I really appreciate your and Greg's work. It's nice to see what can
evolve from a simple quiz idea. :)

Thanks for the kind words.
I think HighLine's methods should either raise EOFError or return nil
if EOF is reached, but I'm not sure which one would be nicer. Maybe a
hybrid approach, like IO#gets and IO#readline?

The trivial script, if the methods return nil:

require 'highline/import'
loop do
name = ask("What's your name?")
if response.nil? or response == 'exit'
puts 'Goodbye, dear friend.'
exit
else
puts "Hello, #{name}!"
end
end

I expect this program to behave like most Unix shells - quietly quit
when one presses Ctrl-D (EOF). But this would print a stack trace, as
shown earlier.

I've added this to our TODO. It will be addressed in the next
version of HighLine.

James Edward Gray II
 

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