diff options
| author | David Terei <davidterei@gmail.com> | 2011-07-20 11:09:03 -0700 |
|---|---|---|
| committer | David Terei <davidterei@gmail.com> | 2011-07-20 11:26:35 -0700 |
| commit | 16514f272fb42af6e9c7674a9bd6c9dce369231f (patch) | |
| tree | e4f332b45fe65e2a7a2451be5674f887b42bf199 /testsuite/tests/typecheck/should_run/T1735_Help/State.hs | |
| parent | ebd422aed41048476aa61dd4c520d43becd78682 (diff) | |
| download | haskell-16514f272fb42af6e9c7674a9bd6c9dce369231f.tar.gz | |
Move tests from tests/ghc-regress/* to just tests/*
Diffstat (limited to 'testsuite/tests/typecheck/should_run/T1735_Help/State.hs')
| -rw-r--r-- | testsuite/tests/typecheck/should_run/T1735_Help/State.hs | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_run/T1735_Help/State.hs b/testsuite/tests/typecheck/should_run/T1735_Help/State.hs new file mode 100644 index 0000000000..7b048eb2df --- /dev/null +++ b/testsuite/tests/typecheck/should_run/T1735_Help/State.hs @@ -0,0 +1,18 @@ +
+module T1735_Help.State where
+
+newtype StateT s m a = StateT { runStateT :: s -> m (a,s) }
+
+instance Monad m => Monad (StateT s m) where
+ return a = StateT $ \s -> return (a, s)
+ m >>= k = StateT $ \s -> do
+ ~(a, s') <- runStateT m s
+ runStateT (k a) s'
+ fail str = StateT $ \_ -> fail str
+
+get :: Monad m => StateT s m s
+get = StateT $ \s -> return (s, s)
+
+put :: Monad m => s -> StateT s m ()
+put s = StateT $ \_ -> return ((), s)
+
|