paiza.ioでelixir その23

# 概要
paiza.ioでelixirやってみた。
yecc使ってみた。

# サンプルコード

```



str = """
Nonterminals list elems elem key_elem.
Terminals '[' ']' ',' int atom key.
Rootsymbol list.

list -> '[' ']'       : [].
list -> '[' elems ']' : '$2'.

key_elem ->  elem elem       : {'$1', '$2'}.
elems -> elem                : ['$1'].
elems -> key_elem            : ['$1'].
elems -> key_elem ',' elems  : ['$1'|'$3'].
elems -> elem ',' elems      : ['$1'|'$3'].

elem -> int  : 'Elixir.Helpers':extract_token('$1').
elem -> atom : 'Elixir.Helpers':extract_token('$1').
elem -> key :  'Elixir.Helpers':extract_token('$1').

elem -> list : '$1'.

Erlang code.
"""
File.write "list_parser.yrl", str
:yecc.file('list_parser.yrl')
{:ok, res} = File.read "list_parser.erl"
IO.puts res


```

# 実行結果

```
-module(list_parser).
-export([parse/1, parse_and_scan/1, format_error/1]).
-file("list_parser.yrl", 20).

-file("/usr/lib/erlang/lib/parsetools-2.1.8/include/yeccpre.hrl", 0).
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2018. 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%
%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 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 ->
            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]).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



-file("list_parser.erl", 177).

-dialyzer({nowarn_function, yeccpars2/7}).
yeccpars2(0=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_0(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(1=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_1(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(2=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_2(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(3=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_3(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(4=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_4(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(5=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_5(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(6=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_6(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(7=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_7(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(8=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_8(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(9=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_9(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(10=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_10(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(11=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_11(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(12=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_12(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(13=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_13(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(14=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_14(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(15=S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_12(S, Cat, Ss, Stack, T, Ts, Tzr);
%% yeccpars2(16=S, Cat, Ss, Stack, T, Ts, Tzr) ->
%%  yeccpars2_16(S, Cat, Ss, Stack, T, Ts, Tzr);
yeccpars2(Other, _, _, _, _, _, _) ->
 erlang:error({yecc_bug,"1.4",{missing_state_in_action_table, Other}}).

-dialyzer({nowarn_function, yeccpars2_0/7}).
yeccpars2_0(S, '[', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 2, Ss, Stack, T, Ts, Tzr);
yeccpars2_0(_, _, _, _, T, _, _) ->
 yeccerror(T).

-dialyzer({nowarn_function, yeccpars2_1/7}).
yeccpars2_1(_S, '$end', _Ss, Stack, _T, _Ts, _Tzr) ->
 {ok, hd(Stack)};
yeccpars2_1(_, _, _, _, T, _, _) ->
 yeccerror(T).

-dialyzer({nowarn_function, yeccpars2_2/7}).
yeccpars2_2(S, '[', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 2, Ss, Stack, T, Ts, Tzr);
yeccpars2_2(S, ']', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 7, Ss, Stack, T, Ts, Tzr);
yeccpars2_2(S, atom, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 8, Ss, Stack, T, Ts, Tzr);
yeccpars2_2(S, int, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 9, Ss, Stack, T, Ts, Tzr);
yeccpars2_2(S, key, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 10, Ss, Stack, T, Ts, Tzr);
yeccpars2_2(_, _, _, _, T, _, _) ->
 yeccerror(T).

yeccpars2_3(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccgoto_elem(hd(Ss), Cat, Ss, Stack, T, Ts, Tzr).

yeccpars2_4(S, ',', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 15, Ss, Stack, T, Ts, Tzr);
yeccpars2_4(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 NewStack = yeccpars2_4_(Stack),
 yeccgoto_elems(hd(Ss), Cat, Ss, NewStack, T, Ts, Tzr).

-dialyzer({nowarn_function, yeccpars2_5/7}).
yeccpars2_5(S, ']', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 14, Ss, Stack, T, Ts, Tzr);
yeccpars2_5(_, _, _, _, T, _, _) ->
 yeccerror(T).

yeccpars2_6(S, ',', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 12, Ss, Stack, T, Ts, Tzr);
yeccpars2_6(S, '[', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 2, Ss, Stack, T, Ts, Tzr);
yeccpars2_6(S, atom, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 8, Ss, Stack, T, Ts, Tzr);
yeccpars2_6(S, int, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 9, Ss, Stack, T, Ts, Tzr);
yeccpars2_6(S, key, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 10, Ss, Stack, T, Ts, Tzr);
yeccpars2_6(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 NewStack = yeccpars2_6_(Stack),
 yeccgoto_elems(hd(Ss), Cat, Ss, NewStack, T, Ts, Tzr).

yeccpars2_7(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 [_|Nss] = Ss,
 NewStack = yeccpars2_7_(Stack),
 yeccgoto_list(hd(Nss), Cat, Nss, NewStack, T, Ts, Tzr).

yeccpars2_8(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 NewStack = yeccpars2_8_(Stack),
 yeccgoto_elem(hd(Ss), Cat, Ss, NewStack, T, Ts, Tzr).

yeccpars2_9(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 NewStack = yeccpars2_9_(Stack),
 yeccgoto_elem(hd(Ss), Cat, Ss, NewStack, T, Ts, Tzr).

yeccpars2_10(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 NewStack = yeccpars2_10_(Stack),
 yeccgoto_elem(hd(Ss), Cat, Ss, NewStack, T, Ts, Tzr).

yeccpars2_11(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 [_|Nss] = Ss,
 NewStack = yeccpars2_11_(Stack),
 yeccgoto_key_elem(hd(Nss), Cat, Nss, NewStack, T, Ts, Tzr).

-dialyzer({nowarn_function, yeccpars2_12/7}).
yeccpars2_12(S, '[', Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 2, Ss, Stack, T, Ts, Tzr);
yeccpars2_12(S, atom, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 8, Ss, Stack, T, Ts, Tzr);
yeccpars2_12(S, int, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 9, Ss, Stack, T, Ts, Tzr);
yeccpars2_12(S, key, Ss, Stack, T, Ts, Tzr) ->
 yeccpars1(S, 10, Ss, Stack, T, Ts, Tzr);
yeccpars2_12(_, _, _, _, T, _, _) ->
 yeccerror(T).

yeccpars2_13(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 [_,_|Nss] = Ss,
 NewStack = yeccpars2_13_(Stack),
 yeccgoto_elems(hd(Nss), Cat, Nss, NewStack, T, Ts, Tzr).

yeccpars2_14(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 [_,_|Nss] = Ss,
 NewStack = yeccpars2_14_(Stack),
 yeccgoto_list(hd(Nss), Cat, Nss, NewStack, T, Ts, Tzr).

%% yeccpars2_15: see yeccpars2_12

yeccpars2_16(_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 [_,_|Nss] = Ss,
 NewStack = yeccpars2_16_(Stack),
 yeccgoto_elems(hd(Nss), Cat, Nss, NewStack, T, Ts, Tzr).

-dialyzer({nowarn_function, yeccgoto_elem/7}).
yeccgoto_elem(2, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_6(6, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_elem(6=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_11(_S, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_elem(12, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_6(6, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_elem(15, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_6(6, Cat, Ss, Stack, T, Ts, Tzr).

-dialyzer({nowarn_function, yeccgoto_elems/7}).
yeccgoto_elems(2, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_5(5, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_elems(12=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_13(_S, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_elems(15=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_16(_S, Cat, Ss, Stack, T, Ts, Tzr).

-dialyzer({nowarn_function, yeccgoto_key_elem/7}).
yeccgoto_key_elem(2, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_4(4, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_key_elem(12, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_4(4, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_key_elem(15, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_4(4, Cat, Ss, Stack, T, Ts, Tzr).

-dialyzer({nowarn_function, yeccgoto_list/7}).
yeccgoto_list(0, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_1(1, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_list(2=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_3(_S, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_list(6=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_3(_S, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_list(12=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_3(_S, Cat, Ss, Stack, T, Ts, Tzr);
yeccgoto_list(15=_S, Cat, Ss, Stack, T, Ts, Tzr) ->
 yeccpars2_3(_S, Cat, Ss, Stack, T, Ts, Tzr).

-compile({inline,yeccpars2_4_/1}).
-file("list_parser.yrl", 6).
yeccpars2_4_(__Stack0) ->
 [__1 | __Stack] = __Stack0,
 [begin
   [ __1 ]
  end | __Stack].

-compile({inline,yeccpars2_6_/1}).
-file("list_parser.yrl", 5).
yeccpars2_6_(__Stack0) ->
 [__1 | __Stack] = __Stack0,
 [begin
   [ __1 ]
  end | __Stack].

-compile({inline,yeccpars2_7_/1}).
-file("list_parser.yrl", 1).
yeccpars2_7_(__Stack0) ->
 [__2,__1 | __Stack] = __Stack0,
 [begin
   [ ]
  end | __Stack].

-compile({inline,yeccpars2_8_/1}).
-file("list_parser.yrl", 11).
yeccpars2_8_(__Stack0) ->
 [__1 | __Stack] = __Stack0,
 [begin
   'Elixir.Helpers' : extract_token ( __1 )
  end | __Stack].

-compile({inline,yeccpars2_9_/1}).
-file("list_parser.yrl", 10).
yeccpars2_9_(__Stack0) ->
 [__1 | __Stack] = __Stack0,
 [begin
   'Elixir.Helpers' : extract_token ( __1 )
  end | __Stack].

-compile({inline,yeccpars2_10_/1}).
-file("list_parser.yrl", 12).
yeccpars2_10_(__Stack0) ->
 [__1 | __Stack] = __Stack0,
 [begin
   'Elixir.Helpers' : extract_token ( __1 )
  end | __Stack].

-compile({inline,yeccpars2_11_/1}).
-file("list_parser.yrl", 4).
yeccpars2_11_(__Stack0) ->
 [__2,__1 | __Stack] = __Stack0,
 [begin
   { __1 , __2 }
  end | __Stack].

-compile({inline,yeccpars2_13_/1}).
-file("list_parser.yrl", 8).
yeccpars2_13_(__Stack0) ->
 [__3,__2,__1 | __Stack] = __Stack0,
 [begin
   [ __1 | __3 ]
  end | __Stack].

-compile({inline,yeccpars2_14_/1}).
-file("list_parser.yrl", 2).
yeccpars2_14_(__Stack0) ->
 [__3,__2,__1 | __Stack] = __Stack0,
 [begin
   __2
  end | __Stack].

-compile({inline,yeccpars2_16_/1}).
-file("list_parser.yrl", 7).
yeccpars2_16_(__Stack0) ->
 [__3,__2,__1 | __Stack] = __Stack0,
 [begin
   [ __1 | __3 ]
  end | __Stack].


-file("list_parser.yrl", 21).

```

# 成果物

https://paiza.io/projects/wIKHRocbYqra8LbSv1zzXw?language=elixir

以上。