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