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{-# LANGUAGE Arrows #-}
-- Failed in ghci
module T where
import Prelude
import Control.Arrow
mapAC :: Arrow arr => Integer -> arr (env, b) c -> arr (env, [b]) [c]
mapAC n farr = go 1
where
go i | i == succ n = arr (\(_env, []) -> [])
| otherwise = proc ~(env, b : bs) ->
do c <- farr -< (env, b)
cs <- go (succ i) -< (env, bs)
returnA -< c : cs
t :: Arrow arr => arr [a] [a]
t = proc ys ->
(| (mapAC 3) (\y -> returnA -< y) |) ys
|
