I've been working through this example from: http://en.wikibooks.org/wiki/Haskell/Understanding_monads
I understand what they're doing all the way up to the definition of (>>), which duplicates Prelude function (>>). To continue following the example, I need to know how to override the Prelude (>>) with the (>>) definition in my file rand.hs.
Michael
==============
[michael@localhost ~]$ cat rand.hs
import System.Random
type Seed = Int
randomNext :: Seed -> Seed
randomNext rand = if newRand > 0 then newRand else newRand + 2147483647
where newRand = 16807 * lo - 2836 * hi
(hi,lo) = rand `divMod` 127773
toDieRoll :: Seed -> Int
toDieRoll seed = (seed `mod` 6) + 1
rollDie :: Seed ->
(Int, Seed)
rollDie seed = ((seed `mod` 6) + 1, randomNext seed)
sumTwoDice :: Seed -> (Int, Seed)
sumTwoDice seed0 =
let (die1, seed1) = rollDie seed0
(die2, seed2) = rollDie seed1
in (die1 + die2, seed2)
(>>) m n = \seed0 ->
let (result1, seed1) = m seed0
(result2, seed2) = n seed1
in (result2, seed2)
[michael@localhost ~]$
|