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

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

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

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

-spec swap({DP, DQ}) -> {DQ, DP}.
swap(Pair) ->
    {A, B} = Pair,
    {B, A}.

-spec map_first({DR, DS}, fun((DR) -> DT)) -> {DT, DS}.
map_first(Pair, Fun) ->
    {A, B} = Pair,
    {Fun(A), B}.

-spec map_second({DU, DV}, fun((DV) -> DW)) -> {DU, DW}.
map_second(Pair, Fun) ->
    {A, B} = Pair,
    {A, Fun(B)}.