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

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

-spec swap({FA, FB}) -> {FB, FA}.
swap(Pair) ->
    {A, B} = Pair,
    {B, A}.

-spec map_first({FC, FD}, fun((FC) -> FE)) -> {FE, FD}.
map_first(Pair, Fun) ->
    {A, B} = Pair,
    {Fun(A), B}.

-spec map_second({FF, FG}, fun((FG) -> FH)) -> {FF, FH}.
map_second(Pair, Fun) ->
    {A, B} = Pair,
    {A, Fun(B)}.

-spec new(FI, FJ) -> {FI, FJ}.
new(First, Second) ->
    {First, Second}.