Make toEqual matcher report the difference between objects

- Mismatches deep within object/array structures are pinpointed with a JsonPath-like syntax.

src/core/matchers/ObjectPath.js

@@ -0,0 +1,47 @@
+getJasmineRequireObj().ObjectPath = function(j$) {
+  function ObjectPath(components) {
+    this.components = components || [];
+  }
+
+  ObjectPath.prototype.toString = function() {
+    if (this.components.length) {
+      return '$' + map(this.components, formatPropertyAccess).join('');
+    } else {
+      return '';
+    }
+  };
+
+  ObjectPath.prototype.add = function(component) {
+    return new ObjectPath(this.components.concat([component]));
+  };
+
+  ObjectPath.prototype.depth = function() {
+    return this.components.length;
+  };
+
+  function formatPropertyAccess(prop) {
+    if (typeof prop === 'number') {
+      return '[' + prop + ']';
+    }
+
+    if (isValidIdentifier(prop)) {
+      return '.' + prop;
+    }
+
+    return '[\'' + prop + '\']';
+  }
+
+  function map(array, fn) {
+    var results = [];
+    for (var i = 0; i < array.length; i++) {
+      results.push(fn(array[i]));
+    }
+    return results;
+  }
+
+  function isValidIdentifier(string) {
+    return /^[A-Za-z\$_][A-Za-z0-9\$_]*$/.test(string);
+  }
+
+  return ObjectPath;
+};