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comparison parser.js @ 0:3d1b8e96f5dc

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Initial commit
author Mike Pavone <pavone@retrodev.com>
date Sun, 18 Mar 2012 12:03:04 -0700
parents
children a57a12bdae96
comparison
equal deleted inserted replaced
-1:000000000000 0:3d1b8e96f5dc
1 var grammar =
2 'start = addsub;' +
3 'addsub = left:muldiv " "* op:("+"/"-") " "* right:addsub [ \\n\\r]* { return {type: "op", left: left, op: op, right: right }; } / muldiv;'+
4 'muldiv = left:primlitsym " "* op:("*"/"/") " "* right:muldiv { return {type: "op", left: left, op: op, right: right }; } / primlitsym;'+
5 'primlitsym = [ \\n\\r]* val:(float / int / string / symbol / object / lambda / "(" expr:addsub " "* ")" { return expr; }) { return val; };' +
6 'symbol = chars:[a-zA-Z_!?@]+ middle:[a-zA-Z_!?@0-9:]* trailing:[a-zA-Z_!?@0-9]* { return {type: "symbol", name: chars.join("") + middle.join("") + trailing.join("")}; };' +
7 'float = digits:[0-9]+ "." decimals:[0-9]+ { return {type: "floatlit", value: parseFloat(digits.join("") + "." + decimals.join("")) }; };' +
8 'int = digits:[0-9]+ { return {type: "intlit", value: parseInt(digits.join(""), 10)}; };' +
9 'string = "\\"" text:[^\\"]* "\\"" { return {type: "strlit", value: text.join("")}; };' +
10 'object = "#{" messages:assignment* "}" { return {type: "object", messages: messages}; };' +
11 'assignment = [ \\n\\r]* sym:symbol " "* "<-" expr:addsub { return {type: "assignment", symbol: sym, expression: expr}; }' +
12 'lambda = args:((& ":") argname+ )? "{" exprs:(assignment / addsub)* [ \\n\\r]* "}" { return {type: "lambda", args: args[1], expressions: exprs}; };' +
13 'argname = chars:[a-zA-Z_!?@:]+ trailing:[a-zA-Z_!?@0-9]* " "* { return {type: "symbol", name: chars.join("") + trailing.join("")}; };';
14 var parser = PEG.buildParser(grammar);
15
16 //var parser = PEG.buildParser('start = expr; expr = int; int = digits:[0-9]+ { return parseInt(digits.join(""), 10); }');
17
18 onReady(function() {
19 q('input[type=button]').onclick = function() {
20 var text = q('textarea').value;
21 try {
22 var parsed = parser.parse(text);
23 q('div').innerHTML = text + "<br><br>" + JSON.stringify(parsed);
24 console.log(parsed);
25 } catch(e) {
26 q('div').innerHTML = e.message + '<br>Line: ' + e.line + '<br>Col: ' + e.column;
27 }
28 }
29 });
30