code: function(bindingsString, bindingContext) {
              try {
                  var viewModel = bindingContext['$data'],
                      scopes = (typeof viewModel == 'object' && viewModel != null) ? [viewModel, bindingContext] : [bindingContext],
                      bindingFunction = createBindingsStringEvaluatorViaCache(bindingsString, scopes.length, this.bindingCache);
                  return bindingFunction(scopes);
              } catch (ex) {
                  throw new Error("Unable to parse bindings.\nMessage: " + ex + ";\nBindings value: " + bindingsString);
              }
          }
docs: The following function is only used internally by this default provider. It's not part of the interface definition for a general binding provider.