A lexical analyzer generator used by jison. It takes a lexical grammar definition (either in JSON or Bison's lexical grammar format) and outputs a JavaScript lexer.
From today (2017/oct/15) the jison-lex repository is obsoleted for the
jison-lexpackage/codebase: the primary source is the jison monorepo'spackages/jison-lex/directory. See also GerHobbelt/jison#16.(For a comparable argument, see also "Why is Babel a monorepo?")
Issues, pull requests, etc. for
jison-lexshould be filed there; hence we do not accept issue reports in this secondary repository any more.This repository will track the primary source for a while still, but be very aware that this particular repository will always be lagging behind!
npm install jison-gho
Then the jison-lex library is located in the subdirectory packages/jison-lex/ of the jison-gho monorepo, i.e. .../node_modules/jison-gho/packages/jison-lex/.
Alternatively, the entire jison-lex API is also available via the jison API itself as can be seen from this internal jison code snippet:
import Lexer from '../packages/jison-lex';
import ebnfParser from '../packages/ebnf-parser';
import lexParser from '../packages/lex-parser';
import grammarPrinter from './util/grammar-printer.js';
import helpers from '../packages/helpers-lib';
var rmCommonWS = helpers.rmCommonWS;
var camelCase = helpers.camelCase;
var code_exec = helpers.exec;
import XRegExp from '@gerhobbelt/xregexp';
import recast from '@gerhobbelt/recast';
import astUtils from '@gerhobbelt/ast-util';
import json5 from '@gerhobbelt/json5';
// Also export other APIs: the JISON module should act as a 'facade' for the others,
// so applications using the JISON compiler itself can rely on it providing everything
// in a guaranteed compatible version as it allows userland code to use the precise
// same APIs as JISON will be using itself:
Jison.Lexer = Lexer;
Jison.ebnfParser = ebnfParser;
Jison.lexParser = lexParser;
Jison.codeExec = code_exec;
Jison.XRegExp = XRegExp;
Jison.recast = recast;
Jison.astUtils = astUtils;
Jison.JSON5 = json5;
Jison.prettyPrint = grammarPrinter;
Jison.rmCommonWS = rmCommonWS;
Jison.mkStdOptions = mkStdOptions;
Jison.camelCase = camelCase;
Jison.autodetectAndConvertToJSONformat = autodetectAndConvertToJSONformat;
...
Jison.Parser = Parser;
export default Jison;
hence you can get at it this way, for example:
import jisonAPI from 'jison-gho';
// get a reference to the full `jison-lex` API:
const jisonLexAPI = jisonAPI.Lexer;
To build the parser yourself, follow the install & build directions of the monorepo.
All
dist/library files are 'self-contained': they include all 'local imports' from within this jison monorepo in order to deliver a choice of source files for your perusal where you only need to worry about importing external dependencies (such asrecast).As such, these
dist/files should be easier to minify and/or use in older (ES5) environments.Iff you use
rollupor similar tools in an ES6/ES2015/ES2017 setting, then thepackage.json::modulehas already been set up for you to use the original sources instead!
Usage: jison-lex [file] [options]
file file containing a lexical grammar
Options:
-o FILE, --outfile FILE Filename and base module name of the generated parser
-t TYPE, --module-type TYPE The type of module to generate (commonjs, js)
--version print version and exit
var JisonLex = require('@gerhobbelt/jison-lex');
var grammar = {
rules: [
["x", "return 'X';" ],
["y", "return 'Y';" ],
["$", "return 'EOF';" ]
]
};
// or load from a file
// var grammar = fs.readFileSync('mylexer.l', 'utf8');
// generate source
var lexerSource = JisonLex.generate(grammar);
// or create a parser in memory
var lexer = new JisonLex(grammar);
lexer.setInput('xyxxy');
lexer.lex();
// => 'X'
lexer.lex();
// => 'Y'
MIT