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

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

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

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

-spec swap({DB, DC}) -> {DC, DB}.
swap(Pair) ->
    {A, B} = Pair,
    {B, A}.

-spec map_first({DD, DE}, fun((DD) -> DF)) -> {DF, DE}.
map_first(Pair, Fun) ->
    {A, B} = Pair,
    {Fun(A), B}.

-spec map_second({DG, DH}, fun((DH) -> DI)) -> {DG, DI}.
map_second(Pair, Fun) ->
    {A, B} = Pair,
    {A, Fun(B)}.