-module(gleam@pair).
-compile(no_auto_import).

-export([first/1, second/1, swap/1, map_first/2, map_second/2]).

-spec first({BK, any()}) -> BK.
first(Pair) ->
    {A, _@1} = Pair,
    A.

-spec second({any(), BN}) -> BN.
second(Pair) ->
    {_@1, A} = Pair,
    A.

-spec swap({BO, BP}) -> {BP, BO}.
swap(Pair) ->
    {A, B} = Pair,
    {B, A}.

-spec map_first({BQ, BR}, fun((BQ) -> BS)) -> {BS, BR}.
map_first(Pair, Fun) ->
    {A, B} = Pair,
    {Fun(A), B}.

-spec map_second({BT, BU}, fun((BU) -> BV)) -> {BT, BV}.
map_second(Pair, Fun) ->
    {A, B} = Pair,
    {A, Fun(B)}.