.TH "Stdlib.Pair" 3 2025-06-09 OCamldoc "OCaml library"
.SH NAME
Stdlib.Pair \- no description
.SH Module
Module   Stdlib.Pair
.SH Documentation
.sp
Module
.BI "Pair"
 : 
.B (module Stdlib__Pair)

.sp

.sp

.sp
.sp

.PP
.SS Pairs

.PP
.I type 
.B ('a, 'b)
.I t 
= 
.B 'a * 'b

.sp
The type for pairs\&.

.sp

.I val make 
: 
.B 'a -> 'b -> 'a * 'b
.sp

.ft B
make a b
.ft R
is the pair 
.ft B
(a, b)
.ft R
\&.

.sp

.I val fst 
: 
.B 'a * 'b -> 'a
.sp

.ft B
fst (a, b)
.ft R
is 
.ft B
a
.ft R
\&.

.sp

.I val snd 
: 
.B 'a * 'b -> 'b
.sp

.ft B
snd (a, b)
.ft R
is 
.ft B
b
.ft R
\&.

.sp

.I val swap 
: 
.B 'a * 'b -> 'b * 'a
.sp

.ft B
swap (a, b)
.ft R
is 
.ft B
(b, a)
.ft R
\&.

.sp

.PP
.SS Iterators

.PP

.I val fold 
: 
.B ('a -> 'b -> 'c) -> 'a * 'b -> 'c
.sp

.ft B
fold f (a, b)
.ft R
applies 
.ft B
f
.ft R
to 
.ft B
a
.ft R
and 
.ft B
b
.ft R
\&.

.sp

.I val map 
: 
.B ('a -> 'c) -> ('b -> 'd) -> 'a * 'b -> 'c * 'd
.sp

.ft B
map f g (a, b)
.ft R
applies 
.ft B
f
.ft R
to 
.ft B
a
.ft R
and 
.ft B
g
.ft R
to 
.ft B
b
.ft R
\&.

.sp

.I val iter 
: 
.B ('a -> unit) -> ('b -> unit) -> 'a * 'b -> unit
.sp

.ft B
iter f g (a, b)
.ft R
first applies 
.ft B
f
.ft R
to 
.ft B
a
.ft R
, and then 
.ft B
g
.ft R
to 
.ft B
b
.ft R
\&.

.sp

.I val map_fst 
: 
.B ('a -> 'c) -> 'a * 'b -> 'c * 'b
.sp

.ft B
map_fst f p
.ft R
applies 
.ft B
f
.ft R
to 
.ft B
p
.ft R
\&'s first component\&.

.sp

.I val map_snd 
: 
.B ('b -> 'c) -> 'a * 'b -> 'a * 'c
.sp

.ft B
map_snd f p
.ft R
applies 
.ft B
f
.ft R
to 
.ft B
p
.ft R
\&'s second component\&.

.sp

.PP
.SS Predicates and comparisons

.PP

.I val equal 
: 
.B ('a -> 'a -> bool) -> ('b -> 'b -> bool) -> 'a * 'b -> 'a * 'b -> bool
.sp

.ft B
equal eqa eqb (a1, b1) (a2, b2)
.ft R
is 
.ft B
true
.ft R
if and only if 
.ft B
eqa a1 a2
.ft R
and
.ft B
eqb b1 b2
.ft R
are both 
.ft B
true
.ft R
\&.

.sp

.I val compare 
: 
.B ('a -> 'a -> int) -> ('b -> 'b -> int) -> 'a * 'b -> 'a * 'b -> int
.sp

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

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