diff options
Diffstat (limited to 'testsuite/tests/typecheck/should_compile/tc087.hs')
-rw-r--r-- | testsuite/tests/typecheck/should_compile/tc087.hs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_compile/tc087.hs b/testsuite/tests/typecheck/should_compile/tc087.hs new file mode 100644 index 0000000000..88317bad35 --- /dev/null +++ b/testsuite/tests/typecheck/should_compile/tc087.hs @@ -0,0 +1,32 @@ +{-# LANGUAGE Rank2Types #-} + +module ShouldSucceed where + +data SeqView t a = Null + | Cons a (t a) + +class PriorityQueue q where + empty :: (Ord a) => q a + single :: (Ord a) => a -> q a + insert :: (Ord a) => a -> q a -> q a + meld :: (Ord a) => q a -> q a -> q a + splitMin :: (Ord a) => q a -> SeqView q a + insert a q = single a `meld` q + +toOrderedList q = case splitMin q of + Null -> [] + Cons a q -> a : toOrderedList q + +insertMany x q = foldr insert q x +pqSort q x = toOrderedList (insertMany x q) + +check :: forall q. (PriorityQueue q) => (forall a. Ord a => q a) -> IO () +check empty = do + putStr "*** sorting\n" + out (pqSort empty [1 .. 99]) + out (pqSort empty [1.0, 1.1 ..99.9]) + +out :: (Num a) => [a] -> IO () +out x | sum x == 0 = putStr "ok\n" + | otherwise = putStr "ok\n" + |