canto34.js

Canto 34 is a library for building recursive-descent parsers.

When it comes to writing a parser, you get two main choices. Write your own, or use a parser generator like PEGJS or Jison. I've never really had much success with parser generators, and it's always seemed pretty easy to write a recursive-descent parser yourself, if you have some basic tools like a regex-based lexer, and some basic functions for matching tokens and reporting errors. Canto34 gives you the functions you need to write a recursive descent parser yourself.

(function(canto34){

your code goes here

A Lexer takes a string and chops it into pieces. A Canto34 Lexer is a series of pattern objects, like

{ 
    name: "whitespace",
    regexp: "[ \t\r\n]+",
    ignore: true
}

	canto34.Lexer = function() {
		this.patterns = [];
	};

    var PatternDefinitionException = function(message) {
    	this.message = message;
    }

	canto34.Lexer.prototype = {
		addPattern: function(pattern) {
			if (!pattern.name) {
				throw new PatternDefinitionException("Patterns must have a 'name' property");
			}

			if (!pattern.regexp) { 
				throw new PatternDefinitionException("Patterns must have a 'regexp' property");
			}

			if (pattern.regexp instanceof RegExp) { 
				throw new PatternDefinitionException("Patterns 'regexp' property must be an instance of RegExp");
			}
		}
	};

})(typeof exports === 'undefined'? this['canto34']={}: exports);