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-- !!! multi-dimensional arrays
module Main ( main ) where
import Control.Monad.ST
import Data.Array.ST
type TwoD s = STArray s Int (STArray s Int Int)
setup :: ST s (TwoD s)
setup = let isz = 10
imax = isz - 1
osz = 2
omax = osz - 1 in
do
-- gives : undefined reference to `IOBase_error_closure'
-- x <- newArray (0, omax) (error "uninitialised")
dmy <- newArray (0, imax) 0
x <- newArray (0, omax) dmy
as <- (sequence . replicate osz) (newArray (0, imax) 6)
mapM_ (\(i,v) -> writeArray x i v) (zip [0..omax] as)
return x
main :: IO ()
main = do
a <- stToIO setup
return ()
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