Module type Applicative_intf.Basic

module type Basic = sig .. end

type 'a t 
val return : 'a -> 'a t
val apply : ('a -> 'b) t ->
'a t -> 'b t
The following identities ought to hold for every Applicative (for some value of =):

Note: <*> is the infix notation for apply.
val map : [ `Custom of
'a t ->
f:('a -> 'b) -> 'b t
| `Define_using_apply ]
The map argument to Applicative.Make says how to implement the applicative's map function. `Define_using_apply means to define map t ~f = return f <*> t. `Custom overrides the default implementation, presumably with something more efficient.

Some other functions returned by Applicative.Make are defined in terms of map, so passing in a more efficient map will improve their efficiency as well.