From: Guillaume Marcais <guslist@...>
Date: 2004-02-05T07:25:53+09:00
Subject: Re: eistein's riddle

Sorry to respond to myself. You posted earlier a description and
implementation of amb in ruby-talk:91075.



On Wed, 2004-02-04 at 14:56, Guillaume Marcais wrote:
> Excuse my ignorance, but what is amb?
> 
> Guillaume.
> 
> On Tue, 2004-02-03 at 21:55, Avi Bryant wrote:
> > Hardly efficient (in fact I haven't yet run it through to completion),
> > but since we were recently talking about amb:
> > ---
> > $colors = ["red", "white", "yellow", "blue", "green"]
> > $nationalities = ["Brit", "Swede", "Dane", "Norwegian", "German"]
> > $beverages = ["tea", "coffee", "milk", "beer", "water"]
> > $cigars = ["Pall Mall", "Blends", "Dunhill", "Prince", "Bluemasters"]
> > $pets = ["dogs", "birds", "cats", "horse", "fish"]
> > 
> > class House
> >   attr_reader :color, :nationality, :beverage, :cigar, :pet
> > 
> >   def initialize
> >     @color = $amb.one_of($colors)
> >     @nationality = $amb.one_of($nationalities)
> >     @beverage = $amb.one_of($beverages)
> >     @cigar = $amb.one_of($cigars)
> >     @pet = $amb.one_of($pets)
> >   end
> > end
> > 
> > def find(property, value)
> >   $houses.detect{|h| h.send(property) == value} || $amb.fail
> > end
> > 
> > def color(s) find(:color, s) end
> > def nationality(s) find(:nationality, s) end
> > def beverage(s) find(:beverage, s) end
> > def cigar(s) find(:cigar, s) end
> > def pet(s) find(:pet, s) end
> > 
> > def next_door(h1, h2)
> >   ($houses.index(h1) - $houses.index(h2)).abs == 1
> > end
> > 
> > $amb = Amb.new
> > $houses = (1..5).collect{House.new}
> > 
> > #fact 1
> > $amb.assert(nationality("Brit").color == "red")
> > #fact 2
> > $amb.assert(nationality("Swede").pet == "dogs")
> > #fact 3
> > $amb.assert(nationality("Dane").beverage == "tea")
> > #fact 4
> > $amb.assert(houses.index(color("white")) -
> > houses.index(color("green")) == 1)
> > #fact 5
> > $amb.assert(color("green").beverage == "coffee")
> > #fact 6
> > $amb.assert(cigar("Pall Mall").pet == "birds")
> > #fact 7
> > $amb.assert(color("yellow").cigar == "Dunhill")
> > #fact 8
> > $amb.assert(houses[2].beverage == "milk")
> > #fact 9
> > $amb.assert(houses[0].nationality == "Norwegian")
> > #fact 10
> > $amb.assert(next_door(cigar("Blends"), pet("cats")))
> > #fact 11
> > $amb.assert(next_door(cigar("Dunhill"), pet("horse")))
> > #fact 12
> > $amb.assert(cigar("Bluemasters").beverage == "beer")
> > #fact 13
> > $amb.assert(nationality("German").cigar == "Prince")
> > #fact 14
> > $amb.assert(next_door(nationality("Norwegian"), color("blue")))
> > #fact 15
> > $amb.assert(next_door(cigar("Blends"), beverage("water")))
> > 
> > #No owners have the same pet, smoke the same brand of cigar
> > #or drink the same beverage.
> > $amb.assert(houses.collect{|h| h.color}.uniq.size == 5)
> > $amb.assert(houses.collect{|h| h.nationality}.uniq.size == 5)
> > $amb.assert(houses.collect{|h| h.beverage}.uniq.size == 5)
> > $amb.assert(houses.collect{|h| h.cigar}.uniq.size == 5)
> > $amb.assert(houses.collect{|h| h.pet}.uniq.size == 5)
> > 
> > puts "The " + pet("fish").nationality + " owns the fish"
> > 
> 
> 
>