add a bench on array vs objects

bin/bench.js

@@ -0,0 +1,110 @@
+/**
+
+Bench to chose between Nested Arrays or Object for AST :
+
+Array Write 4.6 ms
+Object Write 5.6 ms
+
+Array Memory 210 kb
+Object Memory 696 kb
+
+Array Read 1.8 ms
+Object Read 11.8 ms
+
+**/
+
+var memwatch = require('memwatch-next');
+
+function duration(text, hrTime) {
+  var diff = process.hrtime(hrTime);
+  diff = diff[0] * 1000000 + diff[1] / 1000;
+  // console.log(text, Math.round(diff / 1000) + 'ms');
+  return Math.round(diff / 1000);
+}
+
+function runWrite(size) {
+  var result = [];
+  var hrTime = false;
+  var test1 = [];
+  var hd = false, diff = false;
+  // test 1
+  hd = new memwatch.HeapDiff();
+  hrTime = process.hrtime();
+  for(var i = 0; i < size; i++) {
+    test1.push(['class', 'foo', []]);
+  }
+  result.push(
+    duration('Array init time', hrTime)
+  );
+
+  diff = hd.end();
+  result.push(diff.after.size_bytes - diff.before.size_bytes);
+
+  // test 2
+  test1 = [];
+  hd = new memwatch.HeapDiff();
+  hrTime = process.hrtime();
+  for(var i = 0; i < size; i++) {
+    test1.push({type: 'class', name: 'foo', meta: []});
+  }
+  result.push(
+    duration('Object init time', hrTime)
+  );
+  diff = hd.end();
+  result.push(diff.after.size_bytes - diff.before.size_bytes);
+  return result;
+}
+
+
+function runRead(size) {
+  var result = [];
+  var arr = [
+    ['class', 'foo', []]
+  ];
+  var obj = [
+    {type: 'class', name: 'foo', meta: []}
+  ];
+  var ok = false;
+  var hrTime = process.hrtime();  
+  for(var i = 0; i < size; i++) {
+    ok = arr[0][0] === 'class' && arr[0][1] === 'foo';
+  }
+  result.push(
+    duration('Array read time', hrTime)
+  );
+  hrTime = process.hrtime();  
+  for(var i = 0; i < size; i++) {
+    ok = obj[0].type === 'class' && arr[0].name === 'foo';
+  }
+  result.push(
+    duration('Object read time', hrTime)
+  );
+  return result;
+}
+
+var time = [0, 0];
+var memory = [0, 0];
+var size = 10;
+for(var i = 0; i < size; i++) {
+  var result = runWrite(20000);
+  time[0] += result[0];
+  time[1] += result[2];
+  memory[0] += result[1];
+  memory[1] += result[3];
+}
+
+console.log('Array Write', time[0] / size, 'ms');
+console.log('Object Write', time[1] / size, 'ms');
+
+console.log('Array Memory', memory[0] / size / 1024, 'kb');
+console.log('Object Memory', memory[1] / size / 1024, 'kb');
+
+time = [0, 0];
+for(var i = 0; i < size; i++) {
+  var result = runRead(1000000);
+  time[0] += result[0];
+  time[1] += result[1];
+}
+
+console.log('Array Read', time[0] / size, 'ms');
+console.log('Object Read', time[1] / size, 'ms');

package.json

@@ -30,11 +30,12 @@
     }
   ],
   "devDependencies": {
+    "coveralls": "^2.11.2",
     "istanbul": "^0.3.5",
     "jison": "^0.4.15",
-    "mocha": "^2.0.1",
     "jison-lex": "~0.3.4",
     "lex-parser": "~0.1.4",
-    "coveralls": "^2.11.2"
+    "memwatch-next": "^0.2.7",
+    "mocha": "^2.0.1"
   }
 }