fp_gl

-module(fp_gl@non_empty_list).
-compile(no_auto_import).

-export(['of'/1, append/2, append_list/2, to_list/1, prepend/2, prepend_list/2]).
-export_type([non_empty_list/1]).

-type non_empty_list(ELX) :: {non_empty_list, ELX, list(ELX)}.

-spec 'of'(EMA) -> non_empty_list(EMA).
'of'(Head) ->
    {non_empty_list, Head, []}.

-spec append(non_empty_list(EMC), EMC) -> non_empty_list(EMC).
append(Init, End) ->
    {non_empty_list,
     erlang:element(2, Init),
     gleam@list:append(erlang:element(3, Init), [End])}.

-spec append_list(list(EMF), EMF) -> non_empty_list(EMF).
append_list(Init, End) ->
    case Init of
        [] ->
            {non_empty_list, End, []};

        [X | Xs] ->
            {non_empty_list, X, gleam@list:append(Xs, [End])}
    end.

-spec to_list(non_empty_list(EMI)) -> list(EMI).
to_list(It) ->
    gleam@list:append([erlang:element(2, It)], erlang:element(3, It)).

-spec prepend(non_empty_list(EML), EML) -> non_empty_list(EML).
prepend(Tail, Head) ->
    {non_empty_list,
     Head,
     gleam@list:append([erlang:element(2, Tail)], erlang:element(3, Tail))}.

-spec prepend_list(list(EMO), EMO) -> non_empty_list(EMO).
prepend_list(Tail, Head) ->
    {non_empty_list, Head, Tail}.