Filter out loop statements in operator overloading code, to optimize …

…loop execution speed.

src/core/PaperScript.js

@@ -168,7 +168,17 @@ var PaperScript = Base.exports.PaperScript = (function() {
  }
  }
  switch (node && node.type) {
+ case 'UnaryExpression':
+ // -a
+ if (node.operator in unaryOperators
+ && node.argument.type !== 'Literal') {
+ var arg = getCode(node.argument);
+ replaceCode(node, '$_("' + node.operator + '", '
+ + arg + ')');
+ }
+ break;
  case 'BinaryExpression':
+ // a + b, a - b, a / b, a * b, a == b, a % b, ...
  if (node.operator in binaryOperators
  && node.left.type !== 'Literal') {
  var left = getCode(node.left),
@@ -177,22 +187,17 @@ var PaperScript = Base.exports.PaperScript = (function() {
  + '", ' + right + ')');
  }
  break;
- case 'AssignmentExpression':
- if (/^.=$/.test(node.operator)
- && node.left.type !== 'Literal') {
- var left = getCode(node.left),
- right = getCode(node.right);
- replaceCode(node, left + ' = _$_(' + left + ', "'
- + node.operator[0] + '", ' + right + ')');
- }
- break;
  case 'UpdateExpression':
+ // a++, a--
  if (!node.prefix && !(parent && (
+ // Filter out for statements to allow loop increments
+ // to perform well
+ parent.type === 'ForStatement'
  // We need to filter out parents that are comparison
  // operators, e.g. for situations like if (++i < 1),
  // as we can't replace that with if (_$_(i, "+", 1) < 1)
  // Match any operator beginning with =, !, < and >.
- parent.type === 'BinaryExpression'
+ || parent.type === 'BinaryExpression'
  && /^[=!<>]/.test(parent.operator)
  // array[i++] is a MemberExpression with computed = true
  // We can't replace that with array[_$_(i, "+", 1)].
@@ -203,12 +208,15 @@ var PaperScript = Base.exports.PaperScript = (function() {
  + node.operator[0] + '", 1)');
  }
  break;
- case 'UnaryExpression':
- if (node.operator in unaryOperators
- && node.argument.type !== 'Literal') {
- var arg = getCode(node.argument);
- replaceCode(node, '$_("' + node.operator + '", '
- + arg + ')');
+ case 'AssignmentExpression':
+ /// a += b, a -= b
+ if (/^.=$/.test(node.operator)
+ && node.left.type !== 'Literal'
+ && !(parent && parent.type === 'ForStatement')) {
+ var left = getCode(node.left),
+ right = getCode(node.right);
+ replaceCode(node, left + ' = _$_(' + left + ', "'
+ + node.operator[0] + '", ' + right + ')');
  }
  break;
  }