view parser.js @ 2:454c0346f357

Added method call syntax and comparison operators
author Mike Pavone <pavone@retrodev.com>
date Mon, 19 Mar 2012 22:10:38 -0700
parents a57a12bdae96
children a2c3ac7fafa2
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var grammar = 
'start = ws module:(object / lambda) ws { return module; };' +
'ws = [ \\t\\n\\r]*;' +
'hws = [ \\t]*;' +
'expr = e:(funcall / methcall / opexpr) ws { return e; };' +
'opexpr = left:addsub hws op:("<=" / ">=" / "<" / ">" / "=") hws right:opexpr { return {type: "op", left: left, op: op, right: right }; } / addsub;' +
'addsub = left:muldiv hws op:("+"/"-") hws right:addsub { return {type: "op", left: left, op: op, right: right }; } / muldiv;'+
'muldiv = left:primlitsym hws op:("*"/"/") hws right:muldiv { return {type: "op", left: left, op: op, right: right }; } / primlitsym;'+
'primlitsym = hws val:(float / int / string / symbol / object / lambda / "(" expr:expr hws ")" { return expr; }) { return val; };' +
'symbol = chars:[a-zA-Z_!?@]+ trailing:(":"? [a-zA-Z_!?@0-9])* ! ":" { return {type: "symbol", name: chars.join("") + trailing.join("")}; };' +
'float = digits:[0-9]+ "." decimals:[0-9]+ { return {type: "floatlit", value: parseFloat(digits.join("") + "." + decimals.join("")) }; };' +
'int = digits:[0-9]+ { return {type: "intlit", value: parseInt(digits.join(""), 10)}; };' +
'string = "\\"" text:[^\\"]* "\\"" { return {type: "strlit", value: text.join("")}; };' +
'object = "#{" ws messages:assignment* "}" { return {type: "object", messages: messages}; };' +
'assignment = hws sym:symbol hws "<-" expr:expr ws { return {type: "assignment", symbol: sym, expression: expr}; }' +
'lambda = args:((& ":") argname+  )? "{" ws exprs:(assignment / expr)* "}" { return {type: "lambda", args: args[1], expressions: exprs}; };' +
'argname = init:":"? chars:[a-zA-Z_!?@]+ trailing:[a-zA-Z_!?@0-9]* hws { return {type: "symbol", name: init + chars.join("") + trailing.join("")}; };' +
'funcall = hws parts: funcallpart+ { var fun = ""; var args = []; for (var i in parts) { fun += parts[i].name; args = args.concat(parts[i].args); } return {type: "funcall", name: fun, args: args}; };' +
'funcallpart = fun:funpart args:opexpr* hws { return { name: fun, args: args}; };' +
'funpart = chars:[a-zA-Z_!?@]+ middle:[a-zA-Z_!?@0-9]* ":" & [ \\t\\n\\r] { return chars.join("") + middle.join("") + ":"; };' +
'methcall = receiver:opexpr hws info:methcallrest { info.receiver = receiver; return info; };' +
'methcallrest = funcall / unarymeth;' +
'unarymeth = name:symbol { return {type: "funcall", name:name, args: []}; };';
var parser = PEG.buildParser(grammar);

//var parser = PEG.buildParser('start = expr; expr = int; int = digits:[0-9]+ { return parseInt(digits.join(""), 10); }');

onReady(function() {
	q('input[type=button]').onclick = function() {
		var text = q('textarea').value;
		try {
			var parsed = parser.parse(text);
			q('div').innerHTML = text + "<br><br>" + JSON.stringify(parsed);
			console.log(parsed);
		} catch(e) {
			q('div').innerHTML = e.message + '<br>Line: ' + e.line + '<br>Col: ' + e.column;
		}
	}
});