问题
I have see many occurrence of Let value be ?, Return ? sth in the specification.example
Anyone know what is the meaning of the ?.
回答1:
From Algorithm Conventions,
Abstract operations referenced using the functional application style and the method application style that are prefixed by
?indicate that ReturnIfAbrupt should be applied to the resulting Completion Record.For example, ? operationName() is equivalent to ReturnIfAbrupt(operationName()).
Similarly, ? someValue.operationName() is equivalent to ReturnIfAbrupt(someValue.operationName()).
来源：https://stackoverflow.com/questions/41733976/ecmascript-specification-meaning-of-question-mark-in-the-spec