Pair (docs.stdlib.Stdlib.Pair)

Pairs

type ('a, 'b) t = 'a * 'b

The type for pairs.

val make : 'a -> 'b -> 'a * 'b

make a b is the pair (a, b).

val fst : ('a * 'b) -> 'a

fst (a, b) is a.

val snd : ('a * 'b) -> 'b

snd (a, b) is b.

val swap : ('a * 'b) -> 'b * 'a

swap (a, b) is (b, a).

Iterators

val fold : ('a -> 'b -> 'c) -> ('a * 'b) -> 'c

fold f (a, b) applies f to a and b.

val map : ('a -> 'c) -> ('b -> 'd) -> ('a * 'b) -> 'c * 'd

map f g (a, b) applies f to a and g to b.

val iter : ('a -> unit) -> ('b -> unit) -> ('a * 'b) -> unit

iter f g (a, b) first applies f to a, and then g to b.

val map_fst : ('a -> 'c) -> ('a * 'b) -> 'c * 'b

map_fst f p applies f to p's first component.

val map_snd : ('b -> 'c) -> ('a * 'b) -> 'a * 'c

map_snd f p applies f to p's second component.

Predicates and comparisons

val equal : 
  ('a -> 'a -> bool) ->
  ('b -> 'b -> bool) ->
  ('a * 'b) ->
  ('a * 'b) ->
  bool

equal eqa eqb (a1, b1) (a2, b2) is true if and only if eqa a1 a2 and eqb b1 b2 are both true.

val compare : 
  ('a -> 'a -> int) ->
  ('b -> 'b -> int) ->
  ('a * 'b) ->
  ('a * 'b) ->
  int

compare cmpa cmpb is a total order on pairs using cmpa to compare the first component, and cmpb to compare the second component. It is implemented by a lexicographic order.