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Added tag paper_final for changeset 6a12eb22be8c
author Yasutaka Higa <e115763@ie.u-ryukyu.ac.jp>
date Sun, 01 Mar 2015 13:08:51 +0900
parents 1181b4facaf9
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headDelta :: Delta a -> a
headDelta (Mono  x)   = x
headDelta (Delta x _) = x

tailDelta :: Delta a -> Delta a
tailDelta (Mono x)     = Mono x
tailDelta (Delta _ ds) = ds


instance Monad Delta where
  return x = Mono x
  (Mono x) >>= f     = f x
  (Delta x d) >>= f  = Delta (headDelta (f x))
                             (d >>= (tailDelta . f))