Function Environment Record

GetSuperBase():

• Let envRec be the function Environment Record for which the method was invoked.
• Let home be envRec.[[HomeObject]].
• If home has the value undefined, return undefined.
• Return home.[[Prototype]].
• would it better to rename it into GetSuper or GetSuperObject()?

GetThisBinding():

• Assert: envRec.[[ThisBindingStatus]] is not lexical.
• If envRec.[[ThisBindingStatus]] is uninitialized, throw a ReferenceError exception.
• Return envRec.[[ThisValue]].

HasSuperBinding():

• If envRec.[[ThisBindingStatus]] is lexical, return false.
• If envRec.[[HomeObject]] has the value undefined, return false; otherwise, return true.
• zxxu:[[HomeObject]] is meanful only when has super accesses; ecma: [[HomeObject]] is the object that the function is bound to as a method; zxxu: [[HomeObject]] is added since es6 to support class definitions

HasThisBinding(): If envRec.[[ThisBindingStatus]] is lexical, return false; otherwise, return true.

BindThisValue(V):

• Assert: envRec.[[ThisBindingStatus]] is not lexical.
• If envRec.[[ThisBindingStatus]] is initialized, throw a ReferenceError exception.
• Set envRec.[[ThisValue]] to V.
• Set envRec.[[ThisBindingStatus]] to initialized.
• Return V.