mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-10 11:55:49 +00:00
69 lines
1.9 KiB
C++
Executable File
69 lines
1.9 KiB
C++
Executable File
/*
|
|
JSScope.h
|
|
|
|
Scoping facility for JavaScript 2.0.
|
|
|
|
by Patrick C. Beard.
|
|
*/
|
|
|
|
/**
|
|
* Opaque reference to a JavaScript object.
|
|
*/
|
|
class JSObject;
|
|
|
|
/**
|
|
* Opaque reference to a general JavaScript identifier key.
|
|
* This can represent both UNICODE strings, and other more
|
|
* efficient representations, such as hashcodes, etc.
|
|
*/
|
|
class JSIdentifier;
|
|
|
|
/**
|
|
* Some fundamental constants.
|
|
*/
|
|
#define JSNULL (0)
|
|
#define JSUNDEFINED = ((JSObject*)(-1))
|
|
|
|
/**
|
|
* Basic abstraction to associate names with values in a chain of scopes.
|
|
* Can represent any kind of scope, including lexical scopes (closures),
|
|
* namespaces, and classes. Access control can be implemented
|
|
*/
|
|
class JSScope {
|
|
public:
|
|
/**
|
|
* Gets the enclosing scope of this scope (if any).
|
|
* @return enclosing scope or JSNULL if none.
|
|
*/
|
|
virtual JSScope* getParent() = 0;
|
|
|
|
/**
|
|
* Defines a new identifier in the current scope. In a completely static
|
|
* model, this may not be possible, and so this operation will be ignored.
|
|
* @param start the evaluation scope
|
|
* @param id identifier to define
|
|
* @param value optional value to associate with id
|
|
*/
|
|
virtual void defineValue(JSScope* start, JSIndentifier* id, JSObject* value = JSUNDEFINED) = 0;
|
|
|
|
/**
|
|
* Looks up a value corresponding to the given identifier starting
|
|
* with the current scope, and proceeding up the scope chain. If
|
|
* the identifier's is not defined in any of the scopes, the value
|
|
* JSUNDEFINED is returned.
|
|
* @param start the evaluation scope
|
|
* @parm id the identifer to lookup
|
|
* @return result of lookup or JSUNDEFINED
|
|
*/
|
|
virtual JSObject* getValue(JSScope* start, JSIdentifier* id) = 0;
|
|
|
|
/**
|
|
* Associates a value with an identifier in a given scope.
|
|
* @param start the evaluation scope
|
|
* @param id identifier to assign to
|
|
* @param value new value to give to id
|
|
* @return old value associated with identifier
|
|
*/
|
|
virtual JSObject* setValue(JSScope* start, JSIdentifier* id, JSObject* value) = 0;
|
|
};
|