-module(gleam@pair).
-compile([no_auto_import, nowarn_unused_vars]).

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

-spec first({FG, any()}) -> FG.
first(Pair) ->
    {A, _} = Pair,
    A.

-spec second({any(), FJ}) -> FJ.
second(Pair) ->
    {_, A} = Pair,
    A.

-spec swap({FK, FL}) -> {FL, FK}.
swap(Pair) ->
    {A, B} = Pair,
    {B, A}.

-spec map_first({FM, FN}, fun((FM) -> FO)) -> {FO, FN}.
map_first(Pair, Fun) ->
    {A, B} = Pair,
    {Fun(A), B}.

-spec map_second({FP, FQ}, fun((FQ) -> FR)) -> {FP, FR}.
map_second(Pair, Fun) ->
    {A, B} = Pair,
    {A, Fun(B)}.

-spec new(FS, FT) -> {FS, FT}.
new(First, Second) ->
    {First, Second}.