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

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

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

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

-spec swap({DJ, DK}) -> {DK, DJ}.
swap(Pair) ->
    {A, B} = Pair,
    {B, A}.

-spec map_first({DL, DM}, fun((DL) -> DN)) -> {DN, DM}.
map_first(Pair, Fun) ->
    {A, B} = Pair,
    {Fun(A), B}.

-spec map_second({DO, DP}, fun((DP) -> DQ)) -> {DO, DQ}.
map_second(Pair, Fun) ->
    {A, B} = Pair,
    {A, Fun(B)}.