lex-parser

A parser for lexical grammars used by jison

npm install lex-parser
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lex-parser

A parser for lexical grammars used by jison and jison-lex.

install

npm install lex-parser

build

To build the parser yourself, clone the git repo then run:

make

This will generate lex-parser.js.

usage

var lexParser = require("lex-parser");

// parse a lexical grammar and return JSON
lexParser.parse("%% ... ");

example

The parser can parse its own lexical grammar, shown below:

NAME              [a-zA-Z_][a-zA-Z0-9_-]*

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

%%

<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>\n+              /* */
<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>\n+            this.begin('INITIAL')
<options>\s+\n+         this.begin('INITIAL')
<options>\s+            /* empty */

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

<trail>.*\n+                    this.begin('rules')

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

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

\n+                             /* */
\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>(.|\n)+                   return 'CODE'

%%

license

MIT

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