From: mailinglist_abe@...
Date: 2004-10-07T07:43:41+09:00
Subject: Help! Newb having trouble getting a WHY'S example to work...

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Hey, I've been an avid reader of the Why's Poignant Guide to Ruby ever since
I discovered it (poignantguide.net), but while the material is excellent, it
is reduced in effectiveness because I'm reasonably certain that the writer
doesn't run (verbatim anyway) the code that he puts in some of the
tutorials. Namely, I'm having trouble getting a "lottery" tutorial to work,
and I'm too much of a Newb to see easily what the problem is. When I run the
code I get an error like so: "warning: class variable access from toplevel
singleton method"

 

My code is below, would anyone mind please skimming it and letting me know
what the errant code is? I appreciate it!

 

Regards, Abe

 

p.s. the code below is verbatim from the guide itself - I thought that
perhaps I'd mistyped something and so I copied and pasted the code into
Mondrian (the IDE I'm using)

 

class LotteryTicket

 

    NUMERIC_RANGE = 1..25

 

    attr_reader :picks, :purchased

 

    def initialize( *picks )

      if picks.length != 3

        raise ArgumentError, "three numbers must be picked" 

      elsif picks.uniq.length != 3

        raise ArgumentError, "the three picks must be different numbers" 

      elsif picks.detect { |p| not NUMERIC_RANGE === p }

        raise ArgumentError, "the three picks must be numbers between 1 and
25." 

      end

      @picks = picks

      @purchased = Time.now

    end

 

  end

  

  class LotteryTicket

    def self.new_random

      new( rand( 25 ) + 1, rand( 25 ) + 1, rand( 25 ) + 1 )

    rescue ArgumentError

      redo

    end

  end

  

    class LotteryDraw

    @@tickets = {}

    def LotteryDraw.buy( customer, *tickets )

      unless @@tickets.has_key?( customer )

        @@tickets[customer] = []

      end

      @@tickets[customer] += tickets

    end

  end

  

    LotteryDraw.buy 'Yal-dal-rip-sip',

      LotteryTicket.new( 12, 6, 19 ),

      LotteryTicket.new( 5, 1, 3 ),

      LotteryTicket.new( 24, 6, 8 )

      

        class LotteryTicket

    def score( final )

      count = 0

      final.picks.each do |note|

        count +=1 if picks.include? note

      end

      count

    end

  end

  

    class << LotteryDraw

    def play

      final = LotteryTicket.new_random

      winners = {}

      @@tickets.each do |buyer, ticket_list|

        ticket_list.each do |ticket|

          score = ticket.score( final )

          next if score.zero?

          winners[buyer] ||= []

          winners[buyer] << [ ticket, score ]

        end

      end

      @@tickets.clear

      winners

    end

  end

  

  LotteryDraw.play.each do |winner, tickets|

     puts winner + "won on " + tickets.length + " ticket(s)!" 

     tickets.each do |ticket, score|

       puts "\t" + ticket.picks.join( ', ' ) + ": " + score

    end

  end


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