From: Robert Dober <robert.dober@...>
Date: 2007-04-24T17:15:15+09:00
Subject: Re: Cards Class

On 4/23/07, Peter Marsh <evil_grunger@hotmail.com> wrote:
> Hi, I'm an utter newbie to Ruby (and OOP!) and I thought I'd share my
> very first project. It's nothing special - just a simple class that
> simulates a deck of cards, but I'd like to get your comments to see if
> there's anything I can do better (enjoy!):
This is indeed not a bad attempt at all, however ;)
>
> class Deck
>   @@Cards =
> ['Two','Three','Four','Five','Six','Seven','Eight','Nine','Ten','Jack','Queen','King','Ace']
>   @@Suits = ['Spades','Hearts','Diamonds','Club']
Personally I dislike class variables (I prefer class instance
variables even if the make the code more clumpsy (clumpsier?)) but
here it seems to me that constants would be in order, the name of the
cards and suits are constant in the domain after all.

Cards = %w{ Deuce Three Four Five ...
Suits = %w{ Spades Hearts Diamonds Clubs }
>
>   def  initialize
>     @top_card = -1
>     @deck = []
>     52.times do |card|
>       @deck << card
>     end
I will play my personal Ace of Trumps here
@deck = [*0..51]
>   end
>
>   def draw
>     @top_card = @top_card + 1
@top_card += 1
>     if @top_card < 52
>       @deck[@top_card]
>     else
>       raise 'There are only 52 cards in a deck!'
>     end
@deck[@top_card] or raise "There are only 42 cards in the deck ;)"

>   end
>
>   def shuffle
>     @top_card = -1
>     @deck = @deck.sort_by {rand}
>   end
>
>   def suit
>     @@Suits[@top_card/13]
>   end
>
>   def face
>    factor = @top_card/13
>    index = @top_card - 13*factor
>    @@Cards[index]
replace the three by
Cards[ @top_card % 13 ]
>   end

The above two methods seem wrong to me, is it not
@deck[@top_card]
that you want?
>
>   def set_card(card)
>     @top_card=card
>   end
No idea what that should do? If it were not for this method I would
get rid of @top_card at all in your code and write it as follows

def initialize; shuffle end
def shuffle; @deck = [*0..51].sort_by{ rand } end
def draw; @deck.shift or raise "Error only 42 cards" end
def face; Cards[@deck.first % 13] end
def suit; Suits[@deck.first / 13] end


HTH
Robert

-- 
You see things; and you say Why?
But I dream things that never were; and I say Why not?
-- George Bernard Shaw