DYNAMIC DISPATCH FOR CLASSES AND INTERFACES

• US 20080282260A1
• Filed: 05/07/2007
• Published: 11/13/2008
• Est. Priority Date: 05/07/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Meijer, Henricus Johannes Maria, Zhu, Wei, Bozza, Bruno S., Van Gogh, Jeffrey, Beck, Steven Thomas
• Granted Patent: US 7,992,130 B2
• Time in Patent Office: Days
• US Class Current: 719/315
• CPC Class Codes: G06F 9/449 Object-oriented method invocation or resolution

Abstract

Dynamic dispatch for classes and interfaces is encapsulated in a class-less scripting language. A plurality of mechanisms are employed to facilitate dynamic polymorphism. One or more target language constructs such as dictionary objects, prototype objects and/or derived types are utilized to capture class and interface method implementations. These constructs are subsequently referenced at runtime to invoke appropriate code.

Claims

1. A program transformation system, comprising:

an interface component that acquires a representation of a hierarchy of classes and/or interfaces; and

a code generation component that generates code in a class-less script language of equivalent semantics.

2. The system of claim 1, further comprising a virtual constructor component that produces a dispatch construct capturing class and/or interface method implementations to facilitate dynamic dispatch.

3. The system of claim 2, the dispatch construct is a dictionary object.

4. The system of claim 3, the dictionary object maps method names to one or more method implementations.

5. The system of claim 2, the dispatch construct is a linked list.

6. The system of claim 2, the dispatch construct is a prototype object.

7. The system of claim 2, comprising an object creation component that generates a new object with a reference to an associated dispatch construct.

8. The system of claim 2, comprising a call component that translates a virtual method call to a call to a function that identifies a method invocation from the dispatch construct for an object and returns results of execution thereof.

9. The system of claim 2, comprising an optimization component that eliminates dynamic dispatch when a static type is equivalent to a dynamic type of an object and/or lookup can be performed statically.

10. The system of claim 1, the representation is intermediate language code.

11. A method of dynamic dispatch, comprising:

identifying a virtual method call in a class-less script language; and

locating an implementation for the virtual method call at runtime utilizing code that captures class and/or interface inheritances relationships in the language.

12. The method of claim 11, further comprising generating a dispatch construct for objects mapping methods names to implementations.

13. The method of claim 12, comprising generating a dictionary object.

14. The method of claim 12, comprising generating a linked list.

15. The method of claim 12, comprising:

identifying all virtual methods that a class implements directly or indirectly; and

;

determining the most specific implementation of each method by traversing a chain of classes from which the class depends.

16. The method of claim 11, comprising creating objects including reference to an associated dispatch construct identifying method names and implementations.

17. The method of claim 11, locating an implementation comprising looking up the method in a dispatch construct associated with an object type.

18. The method of claim 17, further comprising accessing the dynamic structure through a method function.

19. A program compilation system, comprising:

means for acquiring an inheritance hierarchy of classes represented in intermediate language code;

means for implementing the code semantics in a class-less script programming language.

20. The system of claim 19, further comprising a means for generating a dictionary object including method names and related method implementation to facilitate dynamic dispatch.