lex.l

NAME              [a-zA-Z_][a-zA-Z0-9_-]*
BR                \r\n|\n|\r

%s indented trail rules
%x code start_condition options conditions action

%%

<action>"/*"(.|\n|\r)*?"*/"           return 'ACTION_BODY';
<action>"//".*                        return 'ACTION_BODY';
<action>"/"[^ /]*?['"{}'][^ ]*?"/"    return 'ACTION_BODY'; // regexp with braces or quotes (and no spaces)
<action>\"("\\\\"|'\"'|[^"])*\"       return 'ACTION_BODY';
<action>"'"("\\\\"|"\'"|[^'])*"'"     return 'ACTION_BODY';
<action>[/"'][^{}/"']+                return 'ACTION_BODY';
<action>[^{}/"']+                     return 'ACTION_BODY';
<action>"{"                           yy.depth++; return '{'
<action>"}"                           yy.depth == 0 ? this.begin('trail') : yy.depth--; return '}'

<conditions>{NAME}                    return 'NAME';
<conditions>">"                       this.popState(); return '>';
<conditions>","                       return ',';
<conditions>"*"                       return '*';

<rules>{BR}+                          /* */
<rules>\s+{BR}+                       /* */
<rules>\s+                            this.begin('indented')
<rules>"%%"                           this.begin('code'); return '%%'
<rules>[a-zA-Z0-9_]+                  return 'CHARACTER_LIT'

<options>{NAME}                       yy.options[yytext] = true
<options>{BR}+                        this.begin('INITIAL')
<options>\s+{BR}+                     this.begin('INITIAL')
<options>\s+                          /* empty */

<start_condition>{NAME}               return 'START_COND'
<start_condition>{BR}+                this.begin('INITIAL')
<start_condition>\s+{BR}+             this.begin('INITIAL')
<start_condition>\s+                  /* empty */

<trail>.*{BR}+                        this.begin('rules')

<indented>"{"                         yy.depth = 0; this.begin('action'); return '{'
<indented>"%{"(.|{BR})*?"%}"          this.begin('trail'); yytext = yytext.substr(2, yytext.length-4);return 'ACTION'
"%{"(.|{BR})*?"%}"                    yytext = yytext.substr(2, yytext.length-4); return 'ACTION'
<indented>.+                          this.begin('rules'); return 'ACTION'

"/*"(.|\n|\r)*?"*/"             /* ignore */
"//".*                          /* ignore */

{BR}+                           /* */
\s+                             /* */
{NAME}                          return 'NAME';
\"("\\\\"|'\"'|[^"])*\"         yytext = yytext.replace(/\\"/g,'"'); return 'STRING_LIT';
"'"("\\\\"|"\'"|[^'])*"'"       yytext = yytext.replace(/\\'/g,"'"); return 'STRING_LIT';
"|"                             return '|';
"["("\\\\"|"\]"|[^\]])*"]"      return 'ANY_GROUP_REGEX';
"(?:"                           return 'SPECIAL_GROUP';
"(?="                           return 'SPECIAL_GROUP';
"(?!"                           return 'SPECIAL_GROUP';
"("                             return '(';
")"                             return ')';
"+"                             return '+';
"*"                             return '*';
"?"                             return '?';
"^"                             return '^';
","                             return ',';
"<<EOF>>"                       return '$';
"<"                             this.begin('conditions'); return '<';
"/!"                            return '/!';
"/"                             return '/';
"\\"([0-7]{1,3}|[rfntvsSbBwWdD\\*+()${}|[\]\/.^?]|"c"[A-Z]|"x"[0-9A-F]{2}|"u"[a-fA-F0-9]{4})      return 'ESCAPE_CHAR';
"\\".                           yytext = yytext.replace(/^\\/g,''); return 'ESCAPE_CHAR';
"$"                             return '$';
"."                             return '.';
"%options"                      yy.options = {}; this.begin('options');
"%s"                            this.begin('start_condition'); return 'START_INC';
"%x"                            this.begin('start_condition'); return 'START_EXC';
"%%"                            this.begin('rules'); return '%%';
"{"\d+(","\s?\d+|",")?"}"       return 'RANGE_REGEX';
"{"{NAME}"}"                    return 'NAME_BRACE';
"{"                             return '{';
"}"                             return '}';
.                               /* ignore bad characters */
<*><<EOF>>                      return 'EOF';

<code>(.|{BR})+                 return 'CODE';

%%