Idris2/tests/idris2/interface004/Do.idr

public export
interface Do (0 m : Type) where
  0 Next : m -> Type
  bind : (x : m) -> Next x

public export
Monad m => Do (m a) where
  Next x = {b : Type} -> (a -> m b) -> m b
  bind x k = x >>= k

foo : Maybe Int -> Maybe Int -> Maybe Int
foo x y
   = bind x (\x' =>
     bind y (\y' => Just (x' + y')))
Add test script They don't all pass yet, for minor reasons. Coming shortly... Unfortunately the startup overhead for chez is really noticeable here! 2020-05-19 20:25:18 +03:00			`public export`
[ fix #657 ] RigCount for interface parameters (#808) 2020-12-11 14:58:26 +03:00			`interface Do (0 m : Type) where`
Correct multiplicities when checking Pi binders We've always just used 0, which isn't correct if the function is going to be used in a runtime pattern match. Now calculate correctly so that we're explicit about which type level variables are used at runtime. This might cause some programs to fail to compile, if they use functions that calculate Pi types. The solution is to make those functions explicitly 0 multiplicity. If that doesn't work, you may have been accidentally trying to use compile-time only data at run time! Fixes #1163 2021-03-09 20:23:05 +03:00			`0 Next : m -> Type`
Add test script They don't all pass yet, for minor reasons. Coming shortly... Unfortunately the startup overhead for chez is really noticeable here! 2020-05-19 20:25:18 +03:00			`bind : (x : m) -> Next x`

			`public export`
			`Monad m => Do (m a) where`
			`Next x = {b : Type} -> (a -> m b) -> m b`
			`bind x k = x >>= k`

			`foo : Maybe Int -> Maybe Int -> Maybe Int`
			`foo x y`
			`= bind x (\x' =>`
			`bind y (\y' => Just (x' + y')))`