Commit 12552510a7726dc4b6fe43bdb23a4cd36059ae82 - documents

Added sample implicit module snippet Getty Ritter 9 years ago

1 changed file(s) with 31 addition(s) and 0 deletion(s). Collapse all Expand all

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scraps/implicit.md less more

	1	sig Monad where
	2	type t : * -> *
	3	return : a -> t a
	4	bind : t a -> (a -> t b) -> t b
	5
	6	return : { M : Monad } -> a -> M.t a
	7	return x = M.return x
	8
	9	(>>=) : { M : Monad } -> M.t a -> (a -> M.t b) -> M.t b
	10	(>>=) x f = M.bind x f
	11
	12	map : { M : Monad } -> M.t a -> (a -> b) -> Mt. b
	13	map m f = m >>= (\ x -> return (f x))
	14
	15	join : { M : Monad } -> M.t (M.t a) -> M.t a
	16	join m = m >>= id
	17
	18	unless : { M : Monad } -> Bool -> M.t () -> M.t ()
	19	unless True _ = return ()
	20	unless False m = m
	21
	22	implicit struct MonadOpen where
	23	type t a = Option a
	24	return = Some
	25	bind (Some x) f = f x
	26	bind None _ = None
	27
	28	implicit struct MonadList where
	29	type t a = List a
	30	return x = [x]
	31	bind x f = concat (map f x)