Repaired and improved findSyntaxError function (#470)

This has been broken ever since I changed the code to use an iframe,
since the SyntaxError thrown from evaluating code in the iframe is not
the same as the SyntaxError in the parent frame.

Also made it run the code in strict mode so strict-mode-specific errors
are reported properly, and not include lines that are added by
validation code (and thus don't get included in the editor's line count)

scripts/validate.js

@@ -52,7 +52,8 @@ Game.prototype.validate = function(allCode, playerCode, restartingLevelFromScrip
  }
 
  var allowjQuery = dummyMap._properties.showDummyDom;
- // setup iframe in which code is run. As a side effect, this sets `this._eval` correctly
+ // setup iframe in which code is run. As a side effect, this sets `this._eval`
+ // and `this.SyntaxError` correctly.
  var userEnv = this.initIframe(allowjQuery);
 
  // evaluate the code to get startLevel() and (opt) validateLevel() methods
@@ -109,7 +110,7 @@ Game.prototype.validate = function(allCode, playerCode, restartingLevelFromScrip
  }
 
  var exceptionText = e.toString();
- if (e instanceof SyntaxError) {
+ if (e instanceof this.SyntaxError) {
  var lineNum = this.findSyntaxError(allCode, e.message);
  if (lineNum) {
  exceptionText = "[Line " + lineNum + "] " + exceptionText;
@@ -244,6 +245,7 @@ Game.prototype.initIframe = function(allowjQuery){
  var iframewindow = iframe.contentWindow;
  if (iframewindow.eval) {
  this._eval = iframewindow.eval;
+ this.SyntaxError = iframewindow.SyntaxError;
  }
  // delete any unwated global variables in the iframe
  function purgeObject(object) {
@@ -317,14 +319,25 @@ Game.prototype.secureProperty = function(object, prop, objecttype){
 // of code where a given error occurs
 Game.prototype.findSyntaxError = function(code, errorMsg) {
  var lines = code.split('\n');
+ // One line at the top is the added declarations and doesn't
+ // correspond to any real editor code
+ var phantomLines = 1;
  for (var i = 1; i <= lines.length; i++) {
+ var line = lines[i - 1];
+ var startStartLevel = "map._startOfStartLevelReached()";
+ var endStartLevel = "map._endOfStartLevelReached()";
+ if (line == startStartLevel || line == endStartLevel ) {
+ // This line was added by the editor and doesn't show up to the user
+ // so shouldn't be counted.
+ phantomLines += 1;
+ }
  var testCode = lines.slice(0, i).join('\n');
 
  try {
- this._eval(testCode);
+ this._eval("'use strict';" + testCode);
  } catch (e) {
  if (e.message === errorMsg) {
- return i;
+ return i - phantomLines;
  }
  }
  }