https://github.com/zaach/lex-parser

A parser for lexical grammars used by jison.
https://github.com/zaach/lex-parser

Last synced: about 1 month ago
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A parser for lexical grammars used by jison.

• Host: GitHub
• URL: https://github.com/zaach/lex-parser
• Owner: zaach
• Created: 2012-08-30T07:32:14.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2023-03-18T18:41:15.000Z (almost 2 years ago)
• Last Synced: 2024-04-16T00:26:34.613Z (8 months ago)
• Language: JavaScript
• Size: 116 KB
• Stars: 25
• Watchers: 3
• Forks: 15
• Open Issues: 10
• Metadata Files:
  • Readme: README.md

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README

        
# lex-parser

A parser for lexical grammars used by [jison](http://jison.org) 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

    %%

    [^{}]+          return 'ACTION_BODY'

    "{"             yy.depth++; return '{'

    "}"             yy.depth == 0 ? this.begin('trail') : yy.depth--; return '}'

    {NAME}      return 'NAME'

    ">"         this.popState(); return '>'

    ","         return ','

    "*"         return '*'

    \n+              /* */

    \s+              this.begin('indented')

    "%%"             this.begin('code'); return '%%'

    [a-zA-Z0-9_]+    return 'CHARACTER_LIT'

    {NAME}         yy.options[yytext] = true

    \n+            this.begin('INITIAL')

    \s+\n+         this.begin('INITIAL')

    \s+            /* empty */

    {NAME}         return 'START_COND'

    \n+            this.begin('INITIAL')

    \s+\n+         this.begin('INITIAL')

    \s+            /* empty */

    .*\n+                    this.begin('rules')

    "{"                   yy.depth = 0; this.begin('action'); return '{'

    "%{"(.|\n)*?"%}"      this.begin('trail'); yytext = yytext.substr(2, yytext.length-4);return 'ACTION'

    "%{"(.|\n)*?"%}"                yytext = yytext.substr(2, yytext.length-4); return 'ACTION'

    .+                    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 ','

    "<>"                       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 */

    <*><>                      return 'EOF'

    (.|\n)+                   return 'CODE'


    %%

## license

MIT