module Monad: Monad
module type Basic =sig
..end
module type Infix =sig
..end
val map_via_bind : 'a 'b 'c 'd.
'c ->
f:('a -> 'b) -> return:('b -> 'd) -> bind:('c -> ('a -> 'd) -> 'd) -> 'd
module type S =sig
..end
module Make:
module type Basic2 =sig
..end
module type Infix2 =sig
..end
module type S2 =sig
..end
module Check_S2_refines_S:
module Make2:
map
can be defined in terms of bind
and return
, it is almost always
better to define it directly. We require it in Basic
, which is the argument to
the Make
functor, to encourage direct definition.
For situations where defining map
in terms of bind
is fine, you can do:
let map t ~f = Monad.map_via_bind t ~f ~return ~bind
t >>= f
returns a computation that sequences the computations represented by two
monad elements. The resulting computation first does t
to yield a value v
, and
then runs the computation returned by f v
.t >>| f
is t >>= (fun a -> return (f a))
.bind t f
= t >>= f
return v
returns the (trivial) computation that returns v.map t ~f
is t >>| f.join t
is t >>= (fun t' -> t')
.ignore t
= map t ~f:(fun _ -> ()).('a,'b result)
).