Comments on: Scripting Games in Haskell

By: Michi

Michi — Tue, 26 Feb 2008 18:03:13 +0000

Alistair: You might want to look into F#. I haven’t yet, but it’s a seriously functional language, integrated in the .NET Framework. Its development group is backed by some of the Great Minds behind Haskell.

By: Alistair Young

Alistair Young — Tue, 26 Feb 2008 17:56:07 +0000

I have to poke around for functional language ports to the .NET Framework some more. They make the code so much more short and elegant.

By: Pistahh

Pistahh — Thu, 21 Feb 2008 12:36:36 +0000

Just for reference, here is my python solution

cards = [(1,7),(0,5),(3,7),(2,7),(2,13)]
print sum([(n*(n-1)/2) for n in [[l for _,l in cards].count(x) for x in xrange(1,14)] if n>1])

By: Bas van Dijk

Bas van Dijk — Thu, 21 Feb 2008 10:01:42 +0000

I also like the following:
import Data.List (sort, group)


cards :: [(Int, Int)]

cards = [(1,7),(0,5),(3,7),(2,7),(2,13)]
pairs :: [(Int, Int)] -> Int

pairs = sum . map ((`choose` 2) . length) . group . sort . map snd
-- | Binomial coefficient

-- http://en.wikipedia.org/wiki/Binomial_coefficient

choose :: (Integral a) => a -> a -> a

n `choose` k | n >= k && k >= 0 = fac n `div` (fac k * fac (n - k))

             | otherwise        = 0

fac :: (Num t) => t -> t fac 0 = 1 fac n = n * fac (n-1)

(‘choose’ and ‘fac’ don’t actually belong in this script but should be part of a larger mathematical library.)