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module Main where
import Control.Monad.ST.Lazy
import Data.STRef.Lazy
import Data.Array.ST
import Data.Int
import Debug.Trace
data Refs s = Refs
{ memory :: STArray s Int8 Int8
, pc :: STRef s Int8
}
main :: IO ()
main = do
print $ runST m
where
m = do
m <- newArray_ (0,30)
p <- newSTRef 0
let r = Refs m p
writeArray m 0 0x4
v <- readSTRef p
modifySTRef p (+1)
-- trace ("v: " ++ show v) $ return ()
op <- readArray m v
case {- trace ("v: " ++ show v) $ -} op of
0x4 -> modifySTRef p (+100) -- should run this
n -> error ("should never match this: " ++ show n)
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