Very slow lexing certain files

[ericmj]

Lexing the file below never returns.

It's an erlang file so there's probably something specific to erlang syntax that is causing the issue. It also seems to get exponentially slower based on the size of the file.

File that causes issue

```erlang -module(m3u8). -include("../include/m3u8.hrl"). -export([ parse/1 , download/2 , to_binary/1 , to_file/2 , new/0 , playlist_type/2 , playlist_type/1 , version/2 , version/1 , target_duration/2 , target_duration/1 , media_sequence/2 , media_sequence/1 , program_datetime/2 , program_datetime/1 , allow_cache/2 , allow_cache/1 , iframe_only/2 , iframe_only/1 , segment/2 , segments/1 , segments/2 , key/2 , keys/1 , keys/2 , media/2 , medias/1 , medias/2 , playlist/2 , playlists/1 , playlists/2 , discontinuity/1 , audio_codec_code/1 , video_codec_code/2 , validate/1 , validate/2 ]). -export_type([ uri/0 ]). -type m3u8() :: #{ playlist_type => binary() | undefined , target_duration => integer() | undefined , version => integer() | undefined , media_sequence => integer() | undefined , program_date_time => binary() | undefined , allow_cache => boolean() | undefined , i_frames_only => boolean() | undefined , segments => [segment()] , keys => [key()] , medias => [media()] , playlists => [playlist()] }. -type playlist_type() :: binary(). -type segment() :: #{ duration => integer() | float() % MANDATORY , uri => binary() % MANDATORY , title => binary() % OPTIONAL = <<>> , sub_range_length => integer() % OPTIONAL , sub_range_start => integer() % OPTIONAL } | discontinuity. -type key() :: #{ method => binary() % MANDATORY = <<"NONE">> | <<"AES-128">> , uri => binary() % OPTIONAL , iv => binary() % OPTIONAL , keyformat => binary() % OPTIONAL , keyformatversions => binary() % OPTIONAL } | discontinuity. -type media() :: #{ default => boolean() % OPTIONAL , name => binary() % MANDATORY , uri => binary() % OPTIONAL , type => binary() % MANDATORY , group_id => binary() % MANDATORY , language => binary() % OPTIONAL , autoselect => boolean() % OPTIONAL , forced => boolean() % OPTIONAL , characteristics => binary() % OPTIONAL , assoc_language => binary() % OPTIONAL , stream_id => binary() % OPTIONAL , channels => binary() % OPTIONAL }. -type playlist() :: #{ bandwidth => integer() % MANDATORY , average_bandwidth => integer() % OPTIONAL , frame_rate => float() % OPTIONAL , hdcp_level => binary() % OPTIONAL , program_id => binary() % OPTIONAL , codecs => [binary()] % OPTIONAL , resolution => #{width => integer() % OPTIONAL , height => integer()} , audio => binary() % OPTIONAL , video => binary() % OPTIONAL , subtitles => binary() % OPTIONAL , closed_captions => binary() % OPTIONAL , uri => binary() % MANDATORY } | #{ type => iframe % MANDATORY , bandwidth => integer() % MANDATORY , average_bandwidth => integer() % OPTIONAL , hdcp_level => binary() % OPTIONAL , program_id => binary() % OPTIONAL , codecs => [binary()] % OPTIONAL , resolution => #{width => integer() % OPTIONAL , height => integer()} , video => binary() % OPTIONAL , uri => binary() % MANDATORY }. -type validate_options() :: [{path, string() | binary()} | {recursive, true | false}]. -type uri() :: string() | binary(). % @doc % Download a m3u8 and content. % @end -spec download(URI :: uri(), DestDir :: file:filename_all()) -> {ok, file:filename_all()} | {error, term()}. download(URI, DestDir) -> m3u8_prv_downloader:run(URI, DestDir). % @equiv validate(M3U8, []) -spec validate(M3U8 :: m3u8() | file:filename_all() | binary() | string()) -> ok | {error, [binary()]}. validate(M3U8) -> validate(M3U8, []). % @doc % Validate a m3u8 file % % This function verify if all files referenced in a m3u8 exist. % @end -spec validate(M3U8 :: m3u8() | file:filename_all() | binary() | string(), Options :: validate_options()) -> ok | {error, [string()]}. validate(#{keys := Keys, medias := Medias, playlists := Playlists, segments := Segments}, Options) -> BaseURI = case buclists:keyfind(path, 1, Options, undefined) of undefined -> bucfile:expand_path("."); URI -> bucfile:normalize_path(URI) end, Recursive = buclists:keyfind(recursive, 1, Options, false), case validate_elements( Medias, Recursive, BaseURI, validate_elements( Playlists, Recursive, BaseURI, validate_elements( Segments, false, BaseURI, validate_elements( Keys, false, BaseURI, [])))) of [] -> ok; Errors -> {error, Errors} end; validate(M3U8, Options) -> case parse(M3U8) of {ok, Content} -> validate( Content, case filelib:is_regular(M3U8) of true -> [{path, filename:dirname(bucfile:normalize_path(M3U8))} | Options]; false -> Options end); _ -> {error, [<<"Invalid m3u8">>]} end. validate_elements([], _, _, Errors) -> Errors; validate_elements([#{uri := ElemURI}|Rest], Recursive, BaseURI, Errors) -> case uri_exist(ElemURI, BaseURI) of {local, File, true} -> if Recursive -> case validate(File) of ok -> validate_elements(Rest, Recursive, BaseURI, Errors); {error, OtherErrors} -> validate_elements(Rest, Recursive, BaseURI, Errors ++ OtherErrors) end; true -> validate_elements(Rest, Recursive, BaseURI, Errors) end; {http, _, true} -> validate_elements(Rest, Recursive, BaseURI, Errors); {_, _, false} -> validate_elements(Rest, Recursive, BaseURI, [<<"Missing file: ", (bucs:to_binary(ElemURI))/binary>>|Errors]) end; validate_elements([_|Rest], Recursive, BaseURI, Errors) -> validate_elements(Rest, Recursive, BaseURI, Errors). uri_exist(URI, Base) -> case re:run(URI, "^(http|https)://.*") of nomatch -> File = case re:run(URI, "^(.:\\\\|/).*") of nomatch -> filename:join(Base, URI); _ -> URI end, {local, File, filelib:is_regular(File)}; _ -> case httpc:request(get, {bucs:to_string(URI), []}, [{autoredirect, true}], []) of {ok, {{_, 200, _}, _, _}} -> {http, URI, true}; _ -> {http, URI, false} end end. % @doc % Return a codec code from an audio codec name % @end -spec audio_codec_code(Code :: string() | binary()) -> string() | undefined. audio_codec_code(Code) -> do_audio_codec_code(string:to_lower(bucs:to_string(Code))). do_audio_codec_code("aac-lc") -> "mp4a.40.2"; do_audio_codec_code("he-aac") -> "mp4a.40.5"; do_audio_codec_code("mp3") -> "mp4a.40.34"; do_audio_codec_code(_) -> undefined. % @doc % Return a video codec code from a profile and level. % @end -spec video_codec_code(Profile :: string() | binary(), Level :: float() | string() | binary()) -> string() | undefined. video_codec_code(Profile, Level) -> do_video_codec_code( string:to_lower(bucs:to_string(Profile)), bucs:to_float(Level)). do_video_codec_code("baseline", 3.0) -> "avc1.66.30"; do_video_codec_code("baseline", 3.1) -> "avc1.42001f"; do_video_codec_code("main", 3.0) -> "avc1.77.30"; do_video_codec_code("main", 3.1) -> "avc1.4d001f"; do_video_codec_code("main", 4.0) -> "avc1.4d0028"; do_video_codec_code("main", 4.1) -> "avc1.4d0029"; do_video_codec_code("high", 3.1) -> "avc1.64001f"; do_video_codec_code("high", 4.0) -> "avc1.640028"; do_video_codec_code("high", 4.1) -> "avc1.640029"; do_video_codec_code(_, _) -> undefined. % @doc % Parse a m3u8 file % @end -spec parse(file:filename_all() | uri() | binary() | string()) -> {ok, m3u8()} | {error, term()}. parse(Data) -> case read_m3u8(Data) of {ok, Binary} -> Lines = binary:split(Binary, [<<"\n">>, <<"\r\n">>], [global, trim]), TrimmedLines = lists:map(fun(Data0) -> case string:split(Data0, "##") of [Body|_Comment] -> string:trim(Body, trailing, " "); _ -> "" end end, Lines), m3u8_prv_parser:parse(TrimmedLines, ?M3U8, #{segment => false, header => false, playlist_end => false, playlist => false}); Error -> Error end. read_m3u8(Data) -> case filelib:is_regular(Data) of true -> file:read_file(Data); false -> case bucuri:type(Data) of {ok, _Type} -> case httpc:request(get, {bucs:to_string(Data), []}, [{autoredirect, true}], []) of {ok, {{_Version, 200, _ReasonPhrase}, _Headers, Body}} -> {ok, bucs:to_binary(Body)}; {ok, {{_Version, ErrorCode, _ReasonPhrase}, _Headers, _Body}} -> {error, {http_error, ErrorCode}}; {error, {Reason, _}} -> {error, Reason}; {error, Reason} -> {error, Reason} end; error -> {ok, bucs:to_binary(Data)} end end. % @doc % Generate a m3u8 to binary % @end -spec to_binary(m3u8()) -> binary(). to_binary(M3U8) -> m3u8_prv_writer:to_binary(M3U8). % @doc % Save a m3u8 to file % @end -spec to_file(m3u8(), file:filename_all()) -> ok | {error, term()}. to_file(M3U8, Filename) -> file:write_file(Filename, to_binary(M3U8)). % @doc % Create a new m3u8 % @end -spec new() -> m3u8(). new() -> ?M3U8. % @doc % Set m3u8 version % @end -spec version(m3u8(), integer()) -> {ok, m3u8()} | {error, invalid_version}. version(M3U8, Version) when is_map(M3U8), is_integer(Version) -> {ok, M3U8#{version => Version}}; version(_, _) -> {error, invalid_version}. % @doc % Get m3u8 version % @end -spec version(m3u8()) -> integer() | undefined. version(#{version := Version}) -> Version. % @doc % Set m3u8 target duration % @end -spec target_duration(m3u8(), integer()) -> {ok, m3u8()} | {error, invalid_target_duration}. target_duration(M3U8, TargetDuration) when is_map(M3U8), is_integer(TargetDuration) -> {ok, M3U8#{target_duration => TargetDuration}}; target_duration(_, _) -> {error, invalid_target_duration}. % @doc % Get m3u8 target duration % @end -spec target_duration(m3u8()) -> integer() | undefined. target_duration(#{target_duration := TargetDuration}) -> TargetDuration. % @doc % Set m3u8 playlist type % @end -spec playlist_type(m3u8(), playlist_type()) -> {ok, m3u8()} | {error, invalid_playlist_type}. playlist_type(M3U8, <<"VOD">>) when is_map(M3U8) -> {ok, M3U8#{playlist_type => <<"VOD">>}}; playlist_type(M3U8, <<"EVENT">>) when is_map(M3U8) -> {ok, M3U8#{playlist_type => <<"EVENT">>}}; playlist_type(_, _) -> {error, invalid_playlist_type}. % @doc % Get m3u8 playlist type % @end -spec playlist_type(m3u8()) -> playlist_type() | undefined. playlist_type(#{playlist_type := PlaylistType}) -> PlaylistType. % @doc % Set m3u8 media sequence % @end -spec media_sequence(m3u8(), integer()) -> {ok, m3u8()} | {error, invalid_media_sequence}. media_sequence(M3U8, MediaSequence) when is_map(M3U8), is_integer(MediaSequence) -> {ok, M3U8#{media_sequence => MediaSequence}}; media_sequence(_, _) -> {error, invalid_media_sequence}. % @doc % Get m3u8 media sequence % @end -spec media_sequence(m3u8()) -> integer() | undefined. media_sequence(#{media_sequence := MediaSequence}) -> MediaSequence. % @doc % Set m3u8 program datetime % @end -spec program_datetime(m3u8(), binary()) -> {ok, m3u8()} | {error, invalid_program_date_time}. program_datetime(M3U8, DateTime) when is_map(M3U8), is_binary(DateTime) -> {ok, M3U8#{program_date_time => DateTime}}; program_datetime(_, _) -> {error, invalid_program_date_time}. % @doc % Get m3u8 program datetime % @end -spec program_datetime(m3u8()) -> binary() | undefined. program_datetime(#{program_date_time := ProgramDateTime}) -> ProgramDateTime. % @doc % Set m3u8 allow cache % @end -spec allow_cache(m3u8(), true | false) -> {ok, m3u8()} | {error, invalid_allow_cache}. allow_cache(M3U8, true) when is_map(M3U8) -> {ok, M3U8#{allow_cache => true}}; allow_cache(M3U8, false) when is_map(M3U8) -> {ok, M3U8#{allow_cache => false}}; allow_cache(_, _) -> {error, invalid_allow_cache}. % @doc % Get m3u8 allow cache % @end -spec allow_cache(m3u8()) -> true | false | undefined. allow_cache(#{allow_cache := AllowCache}) -> AllowCache. % @doc % Set m3u8 iframe only % @end -spec iframe_only(m3u8(), true | false) -> {ok, m3u8()} | {error, invalid_i_frame_only}. iframe_only(M3U8, true) when is_map(M3U8) -> {ok, M3U8#{i_frame_only => true}}; iframe_only(M3U8, false) when is_map(M3U8) -> {ok, M3U8#{i_frame_only => false}}; iframe_only(_, _) -> {error, invalid_i_frame_only}. % @doc % Get m3u8 iframe only % @end -spec iframe_only(m3u8()) -> true | false | undefined. iframe_only(#{i_frame_only := AllowCache}) -> AllowCache. % @doc % Add a new segment % @end -spec segment(m3u8(), segment()) -> {ok, m3u8()} | {error, term()}. segment(#{segments := Segments} = M3U8, Segment) when is_map(M3U8), is_list(Segments), is_map(Segment) -> case check_keys(Segment, [{duration, fun erlang:is_integer/1}, {uri, fun erlang:is_binary/1}], [{title, fun erlang:is_binary/1, <<>>}, {sub_range_length, fun erlang:is_integer/1}, {sub_range_start, fun erlang:is_integer/1}]) of {ok, Segment0} -> {ok, M3U8#{segments => Segments ++ [Segment0]}}; Error -> Error end; segment(#{segments := Segments} = M3U8, discontinuity) when is_map(M3U8), is_list(Segments) -> {ok, M3U8#{segments => Segments ++ [discontinuity]}}; segment(_, _) -> {error, invalid_segment}. % @doc % Return the segments list % @end -spec segments(m3u8()) -> [segment()]. segments(#{segments := Segments}) -> Segments. % @doc % Replace all segments % @end -spec segments(m3u8(), [segment()]) -> m3u8(). segments(M3U8, Segments) -> M3U8#{segments => Segments}. % @doc % Add a new key % @end -spec key(m3u8(), key()) -> {ok, m3u8()} | {error, term()}. key(#{keys := Keys} = M3U8, Key) when is_map(M3U8), is_list(Keys), is_map(Key) -> case check_keys(Key, [{method, [<<"NONE">>, <<"AES-128">>]}], [{uri, fun erlang:is_binary/1}, {iv, fun erlang:is_binary/1}, {keyformat, fun erlang:is_binary/1}, {keyformatversions, fun erlang:is_binary/1}]) of {ok, Key0} -> {ok, M3U8#{keys => Keys ++ [Key0]}}; Error -> Error end; key(#{keys := Keys} = M3U8, discontinuity) when is_map(M3U8), is_list(Keys) -> {ok, M3U8#{keys => Keys ++ [discontinuity]}}; key(_, _) -> {error, invalid_key}. % @doc % Return the keys list % @end -spec keys(m3u8()) -> [key()]. keys(#{keys := Keys}) -> Keys. % @doc % Replace all keys % @end -spec keys(m3u8(), [key()]) -> m3u8(). keys(M3U8, Keys) -> M3U8#{keys => Keys}. % @doc % Add a new media % @end -spec media(m3u8(), media()) -> {ok, m3u8()} | {error, term()}. media(#{medias := Medias} = M3U8, Media) when is_map(M3U8), is_list(Medias), is_map(Media) -> case check_keys(Media, [{name, fun erlang:is_binary/1}, {type, fun erlang:is_binary/1}, {group_id, fun erlang:is_binary/1}], [{default, fun erlang:is_boolean/1}, {uri, fun erlang:is_binary/1}, {language, fun erlang:is_binary/1}, {autoselect, fun erlang:is_boolean/1}, {forced, fun erlang:is_boolean/1}, {characteristics, fun erlang:is_binary/1}, {assoc_language, fun erlang:is_binary/1}, {stream_id, fun erlang:is_binary/1}, {channels, fun erlang:is_binary/1}]) of {ok, Media0} -> {ok, M3U8#{medias => Medias ++ [Media0]}}; Error -> Error end; media(_, _) -> {error, invalid_media}. % @doc % Return the medias list % @end -spec medias(m3u8()) -> [media()]. medias(#{medias := Medias}) -> Medias. % @doc % Replace all medias % @end -spec medias(m3u8(), [media()]) -> m3u8(). medias(M3U8, Medias) -> M3U8#{medias => Medias}. % @doc % Add a new playlist % @end -spec playlist(m3u8(), playlist()) -> {ok, m3u8()} | {error, term()}. playlist(#{playlists := Playlists} = M3U8, Playlist) when is_map(M3U8), is_list(Playlists), is_map(Playlist) -> case case maps:get(type, Playlist, undefined) of iframe -> check_keys(Playlist, [{bandwidth, fun erlang:is_integer/1}, {uri, fun erlang:is_binary/1}, {type, fun(X) -> X == iframe end}], [{average_bandwidth, fun erlang:is_integer/1}, {hdcp_level, fun erlang:is_binary/1}, {program_id, fun erlang:is_binary/1}, {codecs, fun(L) -> erlang:is_list(L) andalso lists:all(fun erlang:is_binary/1, L) end}, {resolution, fun (#{width := W, height := H}) -> erlang:is_integer(W) andalso erlang:is_integer(H); (_) -> false end}, {video, fun erlang:is_binary/1}]); _ -> check_keys(Playlist, [{bandwidth, fun erlang:is_integer/1}, {uri, fun erlang:is_binary/1}], [{average_bandwidth, fun erlang:is_integer/1}, {frame_rate, fun erlang:is_float/1}, {hdcp_level, fun erlang:is_binary/1}, {program_id, fun erlang:is_binary/1}, {codecs, fun(L) -> erlang:is_list(L) andalso lists:all(fun erlang:is_binary/1, L) end}, {resolution, fun (#{width := W, height := H}) -> erlang:is_integer(W) andalso erlang:is_integer(H); (_) -> false end}, {audio, fun erlang:is_binary/1}, {video, fun erlang:is_binary/1}, {subtitles, fun erlang:is_binary/1}, {closed_captions, fun erlang:is_binary/1}]) end of {ok, Playlist0} -> {ok, M3U8#{playlists => Playlists ++ [Playlist0]}}; Error -> Error end; playlist(_, _) -> {error, invalid_playlist_iii}. % @doc % Return the playlists list % @end -spec playlists(m3u8()) -> [playlist()]. playlists(#{playlists := Playlists}) -> Playlists. % @doc % Replace all playlists % @end -spec playlists(m3u8(), [playlist()]) -> m3u8(). playlists(M3U8, Playlists) -> M3U8#{playlists => Playlists}. % @doc % Add a segment discontinuity % @end -spec discontinuity(m3u8()) -> {ok, m3u8()} | {error, invalid_discontinuity}. discontinuity(#{segments := Segments, keys := Keys} = M3U8) -> {ok, M3U8#{segments => Segments ++ [discontinuity], keys => Keys ++ [discontinuity]}}; discontinuity(_) -> {error, invalid_discontinuity}. % -- private -- check_keys(Map, Mandatorys, Optionals) -> case mandatories(Mandatorys, Map) of {error, _} = Error -> Error; {Opts, Mands} -> optionals(Optionals, Opts, Mands) end. optionals([], Map, Acc) -> case maps:size(Map) of 0 -> {ok, Acc}; _ -> {error, no_optional_element} end; optionals([{Elem, Check, Alt}|Elems], Map, Acc) -> case maps:get(Elem, Map, '__undefined__') of '__undefined__' -> optionals(Elems, Map, maps:put(Elem, Alt, Acc)); Value -> case check_attr(Value, Check) of true -> optionals(Elems, maps:remove(Elem, Map), maps:put(Elem, Value, Acc)); false -> {error, {invalid_value, Elem, Value}} end end; optionals([{Elem, Check}|Elems], Map, Acc) -> case maps:get(Elem, Map, '__undefined__') of '__undefined__' -> optionals(Elems, Map, Acc); Value -> case check_attr(Value, Check) of true -> optionals(Elems, maps:remove(Elem, Map), maps:put(Elem, Value, Acc)); false -> {error, {invalid_value, Elem, Value}} end end. mandatories(Elems, Map) -> mandatories(Elems, Map, #{}). mandatories([], Map, Acc) -> {Map, Acc}; mandatories([{Elem, Check}|Elems], Map, Acc) -> case maps:get(Elem, Map, '__undefined__') of '__undefined__' -> {error, {missing_mandatory, Elem}}; Value -> case check_attr(Value, Check) of true -> mandatories(Elems, maps:remove(Elem, Map), maps:put(Elem, Value, Acc)); false -> {error, {invalid_value, Elem, Value}} end end. check_attr(_, []) -> false; check_attr(Value, [Check|Checks]) when is_function(Check, 1) -> case Check(Value) of true -> true; false -> check_attr(Value, Checks) end; check_attr(Value, [Value|_]) -> true; check_attr(Value, [_|Checks]) -> check_attr(Value, Checks); check_attr(Value, Check) -> check_attr(Value, [Check]). ```

[josevalim]

@ericmj I cannot reproduce this. I have created this file at the root of this project and executed it with mix run example.exs:

file = ~S"""
% @doc
% Return the segments list
% @end
-spec segments(m3u8()) -> [segment()].
segments(#{segments := Segments}) ->
  Segments.

% @doc
% Replace all segments
% @end
-spec segments(m3u8(), [segment()]) -> m3u8().
segments(M3U8, Segments) ->
  M3U8#{segments => Segments}.

% @doc
% Add a new key
% @end
-spec key(m3u8(), key()) -> {ok, m3u8()} | {error, term()}.
key(#{keys := Keys} = M3U8, Key) when is_map(M3U8),
                                      is_list(Keys),
                                      is_map(Key) ->
  case check_keys(Key,
                  [{method, [<<"NONE">>, <<"AES-128">>]}],
                  [{uri, fun erlang:is_binary/1},
                   {iv, fun erlang:is_binary/1},
                   {keyformat, fun erlang:is_binary/1},
                   {keyformatversions, fun erlang:is_binary/1}]) of
    {ok, Key0} ->
      {ok, M3U8#{keys => Keys ++ [Key0]}};
    Error ->
      Error
  end;
key(#{keys := Keys} = M3U8, discontinuity) when is_map(M3U8),
                                                is_list(Keys) ->
  {ok, M3U8#{keys => Keys ++ [discontinuity]}};
key(_, _) ->
  {error, invalid_key}.

% @doc
% Return the keys list
% @end
-spec keys(m3u8()) -> [key()].
keys(#{keys := Keys}) ->
  Keys.

% @doc
% Replace all keys
% @end
-spec keys(m3u8(), [key()]) -> m3u8().
keys(M3U8, Keys) ->
  M3U8#{keys => Keys}.

% @doc
% Add a new media
% @end
-spec media(m3u8(), media()) -> {ok, m3u8()} | {error, term()}.
media(#{medias := Medias} = M3U8, Media) when is_map(M3U8),
                                              is_list(Medias),
                                              is_map(Media) ->
  case check_keys(Media,
                  [{name, fun erlang:is_binary/1},
                   {type, fun erlang:is_binary/1},
                   {group_id, fun erlang:is_binary/1}],
                  [{default, fun erlang:is_boolean/1},
                   {uri, fun erlang:is_binary/1},
                   {language, fun erlang:is_binary/1},
                   {autoselect, fun erlang:is_boolean/1},
                   {forced, fun erlang:is_boolean/1},
                   {characteristics, fun erlang:is_binary/1},
                   {assoc_language, fun erlang:is_binary/1},
                   {stream_id, fun erlang:is_binary/1},
                   {channels, fun erlang:is_binary/1}]) of
    {ok, Media0} ->
      {ok, M3U8#{medias => Medias ++ [Media0]}};
    Error ->
      Error
  end;
media(_, _) ->
  {error, invalid_media}.

% @doc
% Return the medias list
% @end
-spec medias(m3u8()) -> [media()].
medias(#{medias := Medias}) ->
  Medias.

% @doc
% Replace all medias
% @end
-spec medias(m3u8(), [media()]) -> m3u8().
medias(M3U8, Medias) ->
  M3U8#{medias => Medias}.

% @doc
% Add a new playlist
% @end
-spec playlist(m3u8(), playlist()) -> {ok, m3u8()} | {error, term()}.
playlist(#{playlists := Playlists} = M3U8, Playlist) when is_map(M3U8),
                                                          is_list(Playlists),
                                                          is_map(Playlist) ->
  case case maps:get(type, Playlist, undefined) of
         iframe ->
           check_keys(Playlist,
                      [{bandwidth, fun erlang:is_integer/1},
                       {uri, fun erlang:is_binary/1},
                       {type, fun(X) -> X == iframe end}],
                      [{average_bandwidth, fun erlang:is_integer/1},
                       {hdcp_level, fun erlang:is_binary/1},
                       {program_id, fun erlang:is_binary/1},
                       {codecs, fun(L) ->
                                    erlang:is_list(L) andalso
                                    lists:all(fun erlang:is_binary/1, L)
                                end},
                       {resolution, fun
                                      (#{width := W, height := H}) ->
                                        erlang:is_integer(W) andalso
                                        erlang:is_integer(H);
                                      (_) ->
                                        false
                                    end},
                       {video, fun erlang:is_binary/1}]);
         _ ->
           check_keys(Playlist,
                      [{bandwidth, fun erlang:is_integer/1},
                       {uri, fun erlang:is_binary/1}],
                      [{average_bandwidth, fun erlang:is_integer/1},
                       {frame_rate, fun erlang:is_float/1},
                       {hdcp_level, fun erlang:is_binary/1},
                       {program_id, fun erlang:is_binary/1},
                       {codecs, fun(L) ->
                                    erlang:is_list(L) andalso
                                    lists:all(fun erlang:is_binary/1, L)
                                end},
                       {resolution, fun
                                      (#{width := W, height := H}) ->
                                        erlang:is_integer(W) andalso
                                        erlang:is_integer(H);
                                      (_) ->
                                        false
                                    end},
                       {audio, fun erlang:is_binary/1},
                       {video, fun erlang:is_binary/1},
                       {subtitles, fun erlang:is_binary/1},
                       {closed_captions, fun erlang:is_binary/1}])
       end of
    {ok, Playlist0} ->
      {ok, M3U8#{playlists => Playlists ++ [Playlist0]}};
    Error ->
      Error
  end;
playlist(_, _) ->
  {error, invalid_playlist_iii}.

% @doc
% Return the playlists list
% @end
-spec playlists(m3u8()) -> [playlist()].
playlists(#{playlists := Playlists}) ->
  Playlists.

% @doc
% Replace all playlists
% @end
-spec playlists(m3u8(), [playlist()]) -> m3u8().
playlists(M3U8, Playlists) ->
  M3U8#{playlists => Playlists}.

% @doc
% Add a segment discontinuity
% @end
-spec discontinuity(m3u8()) -> {ok, m3u8()} | {error, invalid_discontinuity}.
discontinuity(#{segments := Segments, keys := Keys} = M3U8) ->
  {ok, M3U8#{segments => Segments ++ [discontinuity],
             keys => Keys ++ [discontinuity]}};
discontinuity(_) ->
  {error, invalid_discontinuity}.

% -- private --

check_keys(Map, Mandatorys, Optionals) ->
  case mandatories(Mandatorys, Map) of
    {error, _} = Error ->
      Error;
    {Opts, Mands} ->
      optionals(Optionals, Opts, Mands)
  end.

optionals([], Map, Acc) ->
  case maps:size(Map) of
    0 ->
      {ok, Acc};
    _ ->
      {error, no_optional_element}
  end;
optionals([{Elem, Check, Alt}|Elems], Map, Acc) ->
  case maps:get(Elem, Map, '__undefined__') of
    '__undefined__' ->
      optionals(Elems, Map, maps:put(Elem, Alt, Acc));
    Value ->
      case check_attr(Value, Check) of
        true ->
          optionals(Elems, maps:remove(Elem, Map), maps:put(Elem, Value, Acc));
        false ->
          {error, {invalid_value, Elem, Value}}
      end
  end;
optionals([{Elem, Check}|Elems], Map, Acc) ->
  case maps:get(Elem, Map, '__undefined__') of
    '__undefined__' ->
      optionals(Elems, Map, Acc);
    Value ->
      case check_attr(Value, Check) of
        true ->
          optionals(Elems, maps:remove(Elem, Map), maps:put(Elem, Value, Acc));
        false ->
          {error, {invalid_value, Elem, Value}}
      end
  end.

mandatories(Elems, Map) ->
  mandatories(Elems, Map, #{}).

mandatories([], Map, Acc) ->
  {Map, Acc};
mandatories([{Elem, Check}|Elems], Map, Acc) ->
  case maps:get(Elem, Map, '__undefined__') of
    '__undefined__' ->
      {error, {missing_mandatory, Elem}};
    Value ->
      case check_attr(Value, Check) of
        true ->
          mandatories(Elems, maps:remove(Elem, Map), maps:put(Elem, Value, Acc));
        false ->
          {error, {invalid_value, Elem, Value}}
      end
  end.
"""

Makeup.highlight(file, lexer: Makeup.Lexers.ElixirLexer)

Are you on latest NimbleParsec + Makeup + MakeupElixir?

[ericmj]

@josevalim I mistakenly only copied and pasted the partial file. I have updated the code block at the top of the issue with the full file and can reproduce it with your script.

[josevalim]

here is a smaller one that still reproduces it:

file = ~S"""
% @doc
% Set m3u8 version
% @end
-spec version(m3u8(), integer()) -> {ok, m3u8()} | {error, invalid_version}.
version(M3U8, Version) when is_map(M3U8), is_integer(Version) ->
  {ok, M3U8#{version => Version}};
version(_, _) ->
  {error, invalid_version}.

% @doc
% Get m3u8 version
% @end
-spec version(m3u8()) -> integer() | undefined.
version(#{version := Version}) ->
  Version.

% @doc
% Set m3u8 target duration
% @end
-spec target_duration(m3u8(), integer()) -> {ok, m3u8()} | {error, invalid_target_duration}.
target_duration(M3U8, TargetDuration) when is_map(M3U8), is_integer(TargetDuration) ->
  {ok, M3U8#{target_duration => TargetDuration}};
target_duration(_, _) ->
  {error, invalid_target_duration}.

% @doc
% Get m3u8 target duration
% @end
-spec target_duration(m3u8()) -> integer() | undefined.
target_duration(#{target_duration := TargetDuration}) ->
  TargetDuration.

% @doc
% Set m3u8 playlist type
% @end
-spec playlist_type(m3u8(), playlist_type()) -> {ok, m3u8()} | {error, invalid_playlist_type}.
playlist_type(M3U8, <<"VOD">>) when is_map(M3U8) ->
  {ok, M3U8#{playlist_type => <<"VOD">>}};
playlist_type(M3U8, <<"EVENT">>) when is_map(M3U8) ->
  {ok, M3U8#{playlist_type => <<"EVENT">>}};
playlist_type(_, _) ->
  {error, invalid_playlist_type}.

% @doc
% Set m3u8 program datetime
% @end
-spec program_datetime(m3u8(), binary()) -> {ok, m3u8()} | {error, invalid_program_date_time}.
program_datetime(M3U8, DateTime) when is_map(M3U8), is_binary(DateTime) ->
  {ok, M3U8#{program_date_time => DateTime}};
program_datetime(_, _) ->
  {error, invalid_program_date_time}.

% @doc
% Set m3u8 allow cache
% @end
-spec allow_cache(m3u8(), true | false) -> {ok, m3u8()} | {error, invalid_allow_cache}.
allow_cache(M3U8, true) when is_map(M3U8) ->
  {ok, M3U8#{allow_cache => true}};
allow_cache(M3U8, false) when is_map(M3U8) ->
  {ok, M3U8#{allow_cache => false}};
allow_cache(_, _) ->
  {error, invalid_allow_cache}.

% @doc
% Set m3u8 iframe only
% @end
-spec iframe_only(m3u8(), true | false) -> {ok, m3u8()} | {error, invalid_i_frame_only}.
iframe_only(M3U8, true) when is_map(M3U8) ->
  {ok, M3U8#{i_frame_only => true}};
iframe_only(M3U8, false) when is_map(M3U8) ->
  {ok, M3U8#{i_frame_only => false}};
iframe_only(_, _) ->
  {error, invalid_i_frame_only}.

% @doc
% Add a new segment
% @end
-spec segment(m3u8(), segment()) -> {ok, m3u8()} | {error, term()}.
segment(#{segments := Segments} = M3U8, Segment) when is_map(M3U8),
                                                      is_list(Segments),
                                                      is_map(Segment) ->
  case check_keys(Segment,
                  [{duration, fun erlang:is_integer/1},
                   {uri, fun erlang:is_binary/1}],
                  [{title, fun erlang:is_binary/1, <<>>},
                   {sub_range_length, fun erlang:is_integer/1},
                   {sub_range_start, fun erlang:is_integer/1}]) of
    {ok, Segment0} ->
      {ok, M3U8#{segments => Segments ++ [Segment0]}};
    Error ->
      Error
  end;
segment(#{segments := Segments} = M3U8, discontinuity) when is_map(M3U8),
                                                            is_list(Segments) ->
  {ok, M3U8#{segments => Segments ++ [discontinuity]}};
segment(_, _) ->
  {error, invalid_segment}.

% @doc
% Add a new key
% @end
-spec key(m3u8(), key()) -> {ok, m3u8()} | {error, term()}.
key(#{keys := Keys} = M3U8, Key) when is_map(M3U8),
                                      is_list(Keys),
                                      is_map(Key) ->
  case check_keys(Key,
                  [{method, [<<"NONE">>, <<"AES-128">>]}],
                  [{uri, fun erlang:is_binary/1},
                   {iv, fun erlang:is_binary/1},
                   {keyformat, fun erlang:is_binary/1},
                   {keyformatversions, fun erlang:is_binary/1}]) of
    {ok, Key0} ->
      {ok, M3U8#{keys => Keys ++ [Key0]}};
    Error ->
      Error
  end;
key(#{keys := Keys} = M3U8, discontinuity) when is_map(M3U8),
                                                is_list(Keys) ->
  {ok, M3U8#{keys => Keys ++ [discontinuity]}};
key(_, _) ->
  {error, invalid_key}.

% @doc
% Add a new media
% @end
-spec media(m3u8(), media()) -> {ok, m3u8()} | {error, term()}.
media(#{medias := Medias} = M3U8, Media) when is_map(M3U8),
                                              is_list(Medias),
                                              is_map(Media) ->
  case check_keys(Media,
                  [{name, fun erlang:is_binary/1},
                   {type, fun erlang:is_binary/1},
                   {group_id, fun erlang:is_binary/1}],
                  [{default, fun erlang:is_boolean/1},
                   {uri, fun erlang:is_binary/1},
                   {language, fun erlang:is_binary/1},
                   {autoselect, fun erlang:is_boolean/1},
                   {forced, fun erlang:is_boolean/1},
                   {characteristics, fun erlang:is_binary/1},
                   {assoc_language, fun erlang:is_binary/1},
                   {stream_id, fun erlang:is_binary/1},
                   {channels, fun erlang:is_binary/1}]) of
    {ok, Media0} ->
      {ok, M3U8#{medias => Medias ++ [Media0]}};
    Error ->
      Error
  end;
media(_, _) ->
  {error, invalid_media}.

% @doc
% Add a new playlist
% @end
-spec playlist(m3u8(), playlist()) -> {ok, m3u8()} | {error, term()}.
playlist(#{playlists := Playlists} = M3U8, Playlist) when is_map(M3U8),
                                                          is_list(Playlists),
                                                          is_map(Playlist) ->
  case case maps:get(type, Playlist, undefined) of
         iframe ->
           check_keys(Playlist,
                      [{bandwidth, fun erlang:is_integer/1},
                       {uri, fun erlang:is_binary/1},
                       {type, fun(X) -> X == iframe end}],
                      [{average_bandwidth, fun erlang:is_integer/1},
                       {hdcp_level, fun erlang:is_binary/1},
                       {program_id, fun erlang:is_binary/1},
                       {codecs, fun(L) ->
                                    erlang:is_list(L) andalso
                                    lists:all(fun erlang:is_binary/1, L)
                                end},
                       {resolution, fun
                                      (#{width := W, height := H}) ->
                                        erlang:is_integer(W) andalso
                                        erlang:is_integer(H);
                                      (_) ->
                                        false
                                    end},
                       {video, fun erlang:is_binary/1}]);
         _ ->
           check_keys(Playlist,
                      [{bandwidth, fun erlang:is_integer/1},
                       {uri, fun erlang:is_binary/1}],
                      [{average_bandwidth, fun erlang:is_integer/1},
                       {frame_rate, fun erlang:is_float/1},
                       {hdcp_level, fun erlang:is_binary/1},
                       {program_id, fun erlang:is_binary/1},
                       {codecs, fun(L) ->
                                    erlang:is_list(L) andalso
                                    lists:all(fun erlang:is_binary/1, L)
                                end},
                       {resolution, fun
                                      (#{width := W, height := H}) ->
                                        erlang:is_integer(W) andalso
                                        erlang:is_integer(H);
                                      (_) ->
                                        false
                                    end},
                       {audio, fun erlang:is_binary/1},
                       {video, fun erlang:is_binary/1},
                       {subtitles, fun erlang:is_binary/1},
                       {closed_captions, fun erlang:is_binary/1}])
       end of
    {ok, Playlist0} ->
      {ok, M3U8#{playlists => Playlists ++ [Playlist0]}};
    Error ->
      Error
  end;
playlist(_, _) ->
  {error, invalid_playlist_iii}.

"""

Makeup.highlight(file, lexer: Makeup.Lexers.ElixirLexer)

[josevalim]

The issue comes when trying to to find matching pairs for tuples (because we use this for highlight on mouse over). This is done by trying to find valid Elixir expressions when we see a {. However, because the program is ultimately not valid, every time we see a {, it ends up traversing the whole program until the end to find out it is not valid, and then moving on to the next expression. The full program traversal happens on every {. We can fix this by giving up if the string is empty at the end.