%% @author Marc Worrell %% @copyright 2014-2026 Marc Worrell %% @doc Grammar for strict CSS parser. Based on http://www.w3.org/TR/CSS21/grammar.html %% @end %% Copyright 2014-2026 Marc Worrell %% %% 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. % FLEX definition from http://www.w3.org/TR/CSS21/grammar.html Definitions. CSS_h = ([0-9a-fA-F]) CSS_nonascii = [\240-\4177777] CSS_unicode = \\{CSS_h}+[\s\r\n\f\t]? CSS_escape = ({CSS_unicode}|\\[^\r\n\f0-9a-fA-F]) CSS_nmstart = ([_a-zA-Z]|{CSS_nonascii}|{CSS_escape}) CSS_nmchar = ([_a-zA-Z0-9-]|{CSS_nonascii}|{CSS_escape}) CSS_string1 = (\"([^\n\r\f\\"]|\\{CSS_nl}|{CSS_escape})*\") CSS_string2 = (\'([^\n\r\f\\']|\\{CSS_nl}|{CSS_escape})*\') CSS_badstring1 = (\"([^\n\r\f\\"]|\\{CSS_nl}|{CSS_escape})*\\?) CSS_badstring2 = (\'([^\n\r\f\\']|\\{CSS_nl}|{CSS_escape})*\\?) CSS_badcomment1 = (\/\*[^*]*\*+([^/*][^*]*\*+)*) CSS_badcomment2 = (\/\*[^*]*(\*+[^/*][^*]*)*) CSS_baduri1 = ([uU][rR][lL]\({CSS_w}([!#$%&*-\[\]-~]|{CSS_nonascii}|{CSS_escape})*{w}) CSS_baduri2 = ([uU][rR][lL]\({CSS_w}{CSS_string}{CSS_w}) CSS_baduri3 = ([uU][rR][lL]\({CSS_w}{CSS_badstring}) CSS_comment = (\/\*[^*]*\*+([^/*][^*]*\*+)*\/) CSS_ident = (-?{CSS_nmstart}{CSS_nmchar}*) CSS_name = ({CSS_nmchar}+) CSS_num = ([0-9]+|[0-9]*\.[0-9]+) CSS_string = ({CSS_string1}|{CSS_string2}) CSS_badstring = ({CSS_badstring1}|{CSS_badstring2}) CSS_badcomment = ({CSS_badcomment1}|{CSS_badcomment2}) CSS_baduri = ({CSS_baduri1}|{CSS_baduri2}|{CSS_baduri3}) CSS_url = ([!#$%&*-~]|{CSS_nonascii}|{CSS_escape})* CSS_s = ([\s\r\n\f\t]+) CSS_w = ({CSS_s}?) CSS_nl = [\n\r\f] A = (a|A|\\0{0,4}(41|61)\s?) B = (b|B|\\0{0,4}(42|62)\s?|\\b|\\B) C = (c|C|\\0{0,4}(43|63)\s?) D = (d|D|\\0{0,4}(44|64)\s?) E = (e|E|\\0{0,4}(45|65)\s?) F = (f|F|\\0{0,4}(46|66)\s?|\\f|\\F) G = (g|G|\\0{0,4}(47|67)\s?|\\g|\\G) H = (h|H|\\0{0,4}(48|68)\s?|\\h|\\H) I = (i|I|\\0{0,4}(49|69)\s?|\\i|\\I) K = (k|K|\\0{0,4}(4b|6b)\s?|\\k|\\K) L = (l|L|\\0{0,4}(4c|6c)\s?|\\l|\\L) M = (m|M|\\0{0,4}(4d|6d)\s?|\\m|\\M) N = (n|N|\\0{0,4}(4e|6e)\s?|\\n|\\N) O = (o|O|\\0{0,4}(4f|6f)\s?|\\o|\\O) P = (p|P|\\0{0,4}(50|70)\s?|\\p|\\P) Q = (q|Q|\\0{0,4}(51|71)\s?|\\q|\\Q) R = (r|R|\\0{0,4}(52|72)\s?|\\r|\\R) S = (s|S|\\0{0,4}(53|73)\s?|\\s|\\S) T = (t|T|\\0{0,4}(54|74)\s?|\\t|\\T) U = (u|U|\\0{0,4}(55|75)\s?|\\u|\\U) V = (v|V|\\0{0,4}(56|76)\s?|\\v|\\V) W = (w|W|\\0{0,4}(57|77)\s?|\\w|\\W) X = (x|X|\\0{0,4}(58|78)\s?|\\x|\\X) Z = (z|Z|\\0{0,4}(5a|7a)\s?|\\z|\\Z) %% Rules. {CSS_s} : skip_token. \/\*[^*]*\*+([^/*][^*]*\*+)*\/ : skip_token. %% /* ignore comments */ {CSS_badcomment} : make_token(badcomment, TokenLine, TokenChars). %% /* unclosed comment at EOF */ : skip_token. ~= : make_token(includes, TokenLine, TokenChars). \|= : make_token(dashmatch, TokenLine, TokenChars). {CSS_string} : make_token(string, TokenLine, TokenChars). {CSS_badstring} : make_token(bad_string, TokenLine, TokenChars). {CSS_ident} : make_token(ident, TokenLine, TokenChars). #{CSS_name} : make_token(hash, TokenLine, TokenChars). @{CSS_ident} : make_at_rule_token(TokenLine, TokenChars). !({w}|{CSS_comment})*{I}{M}{P}{O}{R}{T}{A}{N}{T} : make_token(important_sym, TokenLine, TokenChars). {CSS_num}{CSS_ident} : make_dimension_token(TokenLine, TokenChars). {CSS_num}% : make_token(percentage, TokenLine, TokenChars). {CSS_num} : make_token(number, TokenLine, TokenChars). [uU][rR][lL]\({CSS_w}{CSS_string}{CSS_w}\) : make_token(uri, TokenLine, TokenChars). [uU][rR][lL]\({CSS_w}{CSS_url}{CSS_w}\) : make_token(uri, TokenLine, TokenChars). {CSS_baduri} : make_token(bad_uri, TokenLine, TokenChars). {CSS_ident}\( : make_token(function, TokenLine, TokenChars). . : make_token(literal, TokenLine, TokenChars). % **yytext Erlang code. make_at_rule_token(Line, [$@ | Ident0] = Chars) -> Ident = string:to_lower(css_unescape_ident(Ident0)), make_token(at_rule(Ident), Line, Chars). at_rule("import") -> import_sym; at_rule("font-face") -> font_face_sym; at_rule("page") -> page_sym; at_rule("media") -> media_sym; at_rule("charset") -> charset_sym; at_rule(_) -> bad_at_rule. make_dimension_token(Line, Chars) -> {_Number, Unit0} = lists:splitwith(fun is_num_char/1, Chars), Unit = string:to_lower(css_unescape_ident(Unit0)), make_token(dimension_unit(Unit), Line, Chars). is_num_char(C) when C >= $0, C =< $9 -> true; is_num_char($.) -> true; is_num_char(_) -> false. css_unescape_ident(Unit) -> css_unescape_ident(Unit, []). css_unescape_ident([], Acc) -> lists:reverse(Acc); css_unescape_ident([$\\, C | Rest], Acc) -> case is_hex(C) of true -> {Hex, Rest1} = take_hex([C|Rest], 6, []), Codepoint0 = list_to_integer(Hex, 16), Codepoint = case Codepoint0 of 0 -> 16#FFFD; C1 when C1 > 16#10FFFF -> 16#FFFD; C1 when C1 >= 16#D800, C1 =< 16#DFFF -> 16#FFFD; C1 -> C1 end, Rest2 = skip_css_ws(Rest1), css_unescape_ident(Rest2, [Codepoint | Acc]); false -> css_unescape_ident(Rest, [C | Acc]) end; css_unescape_ident([$\\], Acc) -> lists:reverse([$\\ | Acc]); css_unescape_ident([C | Rest], Acc) -> css_unescape_ident(Rest, [C | Acc]). is_hex(C) when C >= $0, C =< $9 -> true; is_hex(C) when C >= $a, C =< $f -> true; is_hex(C) when C >= $A, C =< $F -> true; is_hex(_) -> false. take_hex(Rest, 0, Acc) -> {lists:reverse(Acc), Rest}; take_hex([C|Rest], N, Acc) when N > 0 -> case is_hex(C) of true -> take_hex(Rest, N-1, [C|Acc]); false -> {lists:reverse(Acc), [C|Rest]} end; take_hex(Rest, _N, Acc) -> {lists:reverse(Acc), Rest}. skip_css_ws([C|Rest]) when C =:= $\s; C =:= $\t; C =:= $\r; C =:= $\n; C =:= $\f -> Rest; skip_css_ws(Rest) -> Rest. dimension_unit("em") -> ems; dimension_unit("ex") -> exs; dimension_unit("cap") -> length; dimension_unit("ch") -> length; dimension_unit("ic") -> length; dimension_unit("lh") -> length; dimension_unit("rem") -> length; dimension_unit("rex") -> length; dimension_unit("rcap") -> length; dimension_unit("rch") -> length; dimension_unit("ric") -> length; dimension_unit("rlh") -> length; dimension_unit("px") -> length; dimension_unit("cm") -> length; dimension_unit("mm") -> length; dimension_unit("q") -> length; dimension_unit("in") -> length; dimension_unit("pt") -> length; dimension_unit("pc") -> length; dimension_unit("vw") -> length; dimension_unit("vh") -> length; dimension_unit("vi") -> length; dimension_unit("vb") -> length; dimension_unit("vmin") -> length; dimension_unit("vmax") -> length; dimension_unit("svw") -> length; dimension_unit("svh") -> length; dimension_unit("svi") -> length; dimension_unit("svb") -> length; dimension_unit("svmin") -> length; dimension_unit("svmax") -> length; dimension_unit("lvw") -> length; dimension_unit("lvh") -> length; dimension_unit("lvi") -> length; dimension_unit("lvb") -> length; dimension_unit("lvmin") -> length; dimension_unit("lvmax") -> length; dimension_unit("dvw") -> length; dimension_unit("dvh") -> length; dimension_unit("dvi") -> length; dimension_unit("dvb") -> length; dimension_unit("dvmin") -> length; dimension_unit("dvmax") -> length; dimension_unit("cqw") -> length; dimension_unit("cqh") -> length; dimension_unit("cqi") -> length; dimension_unit("cqb") -> length; dimension_unit("cqmin") -> length; dimension_unit("cqmax") -> length; dimension_unit("deg") -> angle; dimension_unit("rad") -> angle; dimension_unit("grad") -> angle; dimension_unit("turn") -> angle; dimension_unit("ms") -> time; dimension_unit("s") -> time; dimension_unit("hz") -> freq; dimension_unit("khz") -> freq; dimension_unit("dpi") -> resolution; dimension_unit("dpcm") -> resolution; dimension_unit("dppx") -> resolution; dimension_unit("x") -> resolution; dimension_unit(_) -> dimension. make_token(literal, Line, ";") -> {token, {';', Line, ";"}}; make_token(literal, Line, "{") -> {token, {'{', Line, "{"}}; make_token(literal, Line, "}") -> {token, {'}', Line, "}"}}; make_token(literal, Line, "[") -> {token, {'[', Line, "["}}; make_token(literal, Line, "]") -> {token, {']', Line, "]"}}; make_token(literal, Line, "(") -> {token, {'(', Line, "("}}; make_token(literal, Line, ")") -> {token, {')', Line, ")"}}; make_token(literal, Line, ",") -> {token, {',', Line, ","}}; make_token(literal, Line, ".") -> {token, {'.', Line, "."}}; make_token(literal, Line, ":") -> {token, {':', Line, ":"}}; make_token(literal, Line, "/") -> {token, {'/', Line, "/"}}; make_token(literal, Line, "-") -> {token, {'-', Line, "-"}}; make_token(literal, Line, "+") -> {token, {'+', Line, "+"}}; make_token(literal, Line, "*") -> {token, {'*', Line, "*"}}; make_token(literal, Line, ">") -> {token, {'>', Line, ">"}}; make_token(literal, Line, "=") -> {token, {'=', Line, "="}}; make_token(literal, Line, [Char] = Chars) -> {token, {Char, Line, Chars}}; make_token(Name, Line, Chars) -> {token, {Name, Line, Chars}}.