%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2017. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%

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% The parser generator will insert appropriate declarations before this line.%

-type yecc_ret() :: {'error', _} | {'ok', _}.

-spec parse(Tokens :: list()) -> yecc_ret().
parse(Tokens) ->
    yeccpars0(Tokens, {no_func, no_line}, 0, [], []).

-spec parse_and_scan({function() | {atom(), atom()}, [_]}
                     | {atom(), atom(), [_]}) -> yecc_ret().
parse_and_scan({F, A}) ->
    yeccpars0([], {{F, A}, no_line}, 0, [], []);
parse_and_scan({M, F, A}) ->
    Arity = length(A),
    yeccpars0([], {{fun M:F/Arity, A}, no_line}, 0, [], []).

-spec format_error(any()) -> [char() | list()].
format_error(Message) ->
    case io_lib:deep_char_list(Message) of
        true ->
            Message;
        _ ->
            io_lib:write(Message)
    end.

%% To be used in grammar files to throw an error message to the parser
%% toplevel. Doesn't have to be exported!
-compile({nowarn_unused_function, return_error/2}).
-spec return_error(integer(), any()) -> no_return().
return_error(Line, Message) ->
    throw({error, {Line, ?MODULE, Message}}).

-define(CODE_VERSION, "1.4").

yeccpars0(Tokens, Tzr, State, States, Vstack) ->
    try yeccpars1(Tokens, Tzr, State, States, Vstack)
    catch 
        error: Error ->
            Stacktrace = erlang:get_stacktrace(),
            try yecc_error_type(Error, Stacktrace) of
                Desc ->
                    erlang:raise(error, {yecc_bug, ?CODE_VERSION, Desc},
                                 Stacktrace)
            catch _:_ -> erlang:raise(error, Error, Stacktrace)
            end;
        %% Probably thrown from return_error/2:
        throw: {error, {_Line, ?MODULE, _M}} = Error ->
            Error
    end.

yecc_error_type(function_clause, [{?MODULE,F,ArityOrArgs,_} | _]) ->
    case atom_to_list(F) of
        "yeccgoto_" ++ SymbolL ->
            {ok,[{atom,_,Symbol}],_} = erl_scan:string(SymbolL),
            State = case ArityOrArgs of
                        [S,_,_,_,_,_,_] -> S;
                        _ -> state_is_unknown
                    end,
            {Symbol, State, missing_in_goto_table}
    end.

yeccpars1([Token | Tokens], Tzr, State, States, Vstack) ->
    yeccpars2(State, element(1, Token), States, Vstack, Token, Tokens, Tzr);
yeccpars1([], {{F, A},_Line}, State, States, Vstack) ->
    case apply(F, A) of
        {ok, Tokens, Endline} ->
            yeccpars1(Tokens, {{F, A}, Endline}, State, States, Vstack);
        {eof, Endline} ->
            yeccpars1([], {no_func, Endline}, State, States, Vstack);
        {error, Descriptor, _Endline} ->
            {error, Descriptor}
    end;
yeccpars1([], {no_func, no_line}, State, States, Vstack) ->
    Line = 999999,
    yeccpars2(State, '$end', States, Vstack, yecc_end(Line), [],
              {no_func, Line});
yeccpars1([], {no_func, Endline}, State, States, Vstack) ->
    yeccpars2(State, '$end', States, Vstack, yecc_end(Endline), [],
              {no_func, Endline}).

%% yeccpars1/7 is called from generated code.
%%
%% When using the {includefile, Includefile} option, make sure that
%% yeccpars1/7 can be found by parsing the file without following
%% include directives. yecc will otherwise assume that an old
%% yeccpre.hrl is included (one which defines yeccpars1/5).
yeccpars1(State1, State, States, Vstack, Token0, [Token | Tokens], Tzr) ->
    yeccpars2(State, element(1, Token), [State1 | States],
              [Token0 | Vstack], Token, Tokens, Tzr);
yeccpars1(State1, State, States, Vstack, Token0, [], {{_F,_A}, _Line}=Tzr) ->
    yeccpars1([], Tzr, State, [State1 | States], [Token0 | Vstack]);
yeccpars1(State1, State, States, Vstack, Token0, [], {no_func, no_line}) ->
    Line = yecctoken_end_location(Token0),
    yeccpars2(State, '$end', [State1 | States], [Token0 | Vstack],
              yecc_end(Line), [], {no_func, Line});
yeccpars1(State1, State, States, Vstack, Token0, [], {no_func, Line}) ->
    yeccpars2(State, '$end', [State1 | States], [Token0 | Vstack],
              yecc_end(Line), [], {no_func, Line}).

%% For internal use only.
yecc_end({Line,_Column}) ->
    {'$end', Line};
yecc_end(Line) ->
    {'$end', Line}.

yecctoken_end_location(Token) ->
    try erl_anno:end_location(element(2, Token)) of
        undefined -> yecctoken_location(Token);
        Loc -> Loc
    catch _:_ -> yecctoken_location(Token)
    end.

-compile({nowarn_unused_function, yeccerror/1}).
yeccerror(Token) ->
    Text = yecctoken_to_string(Token),
    Location = yecctoken_location(Token),
    {error, {Location, ?MODULE, ["syntax error before: ", Text]}}.

-compile({nowarn_unused_function, yecctoken_to_string/1}).
yecctoken_to_string(Token) ->
    try erl_scan:text(Token) of
        undefined -> yecctoken2string(Token);
        Txt -> Txt
    catch _:_ -> yecctoken2string(Token)
    end.

yecctoken_location(Token) ->
    try erl_scan:location(Token)
    catch _:_ -> element(2, Token)
    end.

-compile({nowarn_unused_function, yecctoken2string/1}).
yecctoken2string({atom, _, A}) -> io_lib:write_atom(A);
yecctoken2string({integer,_,N}) -> io_lib:write(N);
yecctoken2string({float,_,F}) -> io_lib:write(F);
yecctoken2string({char,_,C}) -> io_lib:write_char(C);
yecctoken2string({var,_,V}) -> io_lib:format("~s", [V]);
yecctoken2string({string,_,S}) -> io_lib:write_string(S);
yecctoken2string({reserved_symbol, _, A}) -> io_lib:write(A);
yecctoken2string({_Cat, _, Val}) -> io_lib:format("~tp", [Val]);
yecctoken2string({dot, _}) -> "'.'";
yecctoken2string({'$end', _}) -> [];
yecctoken2string({Other, _}) when is_atom(Other) ->
    io_lib:write_atom(Other);
yecctoken2string(Other) ->
    io_lib:format("~tp", [Other]).

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