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author | David Terei <davidterei@gmail.com> | 2011-07-20 11:09:03 -0700 |
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committer | David Terei <davidterei@gmail.com> | 2011-07-20 11:26:35 -0700 |
commit | 16514f272fb42af6e9c7674a9bd6c9dce369231f (patch) | |
tree | e4f332b45fe65e2a7a2451be5674f887b42bf199 /testsuite/tests/gadt/arrow.hs | |
parent | ebd422aed41048476aa61dd4c520d43becd78682 (diff) | |
download | haskell-16514f272fb42af6e9c7674a9bd6c9dce369231f.tar.gz |
Move tests from tests/ghc-regress/* to just tests/*
Diffstat (limited to 'testsuite/tests/gadt/arrow.hs')
-rw-r--r-- | testsuite/tests/gadt/arrow.hs | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/testsuite/tests/gadt/arrow.hs b/testsuite/tests/gadt/arrow.hs new file mode 100644 index 0000000000..1abc535a0b --- /dev/null +++ b/testsuite/tests/gadt/arrow.hs @@ -0,0 +1,24 @@ +{-# LANGUAGE GADTs #-} + +module Opt where +import Control.Arrow +import Control.Category +import Prelude hiding (id, (.)) + +data Opt arr a b where + Lift :: arr a b -> Opt arr a b + First :: Opt arr a b -> Opt arr (a,c) (b,c) + +runOpt :: Arrow arr => Opt arr a b -> arr a b +runOpt (Lift f) = f +runOpt (First f) = first (runOpt f) + +instance Arrow arr => Category (Opt arr) where + id = Lift id + First f . First g = First (f . g) + f . g = Lift (runOpt f . runOpt g) + +instance Arrow arr => Arrow (Opt arr) where + arr = Lift . arr + + first = First |