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igrep/associative-law.hs

Created December 19, 2018 06:28
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(HAS TYPE ERROR) Test associative law for type-level append (++)
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associative-law.hs
#!/bin/env stack
{-
stack --resolver=lts-12.24 script --package extensible
-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE OverloadedLabels #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeOperators #-}
import Data.Extensible
main :: IO ()
main = print $ happend3 (#x @== True <: nil) (#y @== True <: nil) (#z @== True <: nil)
happend3 :: Record xs -> Record ys -> Record zs -> Record (xs ++ ys ++ zs)
happend3 xs ys zs = xs `happend` ys `happend` zs
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igrep commented Jan 4, 2019

Fixed by https://gist.github.com/notogawa/13422a72683d05cee989d60cd64479a2
Thanks notogawa!

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