US 2007/0168949 A1 · System supporting object-oriented constructs in ECMAScript

Abstract

An internally consistent system implementing object-oriented programming constructs in ECMAScript is described. First, a function, rather than the ECMAScript new keyword, is used to initiate new instance creation. The instance creation function is assigned to a non-Function instance rather than an instance of Function as required for use of new. Instances with attached instance creation functions serve as “type proxy” objects and replace the Function instances normally used as types. Since the type proxies and prototype chains created and maintained by the invention are instances of normal objects, rather than instances of Function as required by standard ECMAScript, this approach allows native ECMAScript lookup semantics to be leveraged while supporting inheritance of both state and behavior for instances and types to any level desired. A set of functions known herein as property-definition functions are used by type proxies to assign properties as global, local, instance, or type properties rather than the standard ECMAScript approach of direct assignment. Where constraints exist such as “read-only”, “private”, etc. the physical storage of the property may be located away from the target object in a separate storage structure. Method definitions further place a “backstop” method on Object.prototype. Invocation of the backstop triggers a callback to the non-implementing receiver followed by a scan of guardians for multiple inheritance, followed by dynamic type conversion and method creation. The result is a highly enhanced system of polymorphic behavior.

Claims26

Dependent claims

A method for implementing type inheritance and instance inheritance in JavaScript, comprising the steps of:

creating a first Function instance (F1);
creating a second Function instance (F2);
creating a type object (T) from F1;
assigning F1 as T's type constructor or T's subtype prototype constructor;
and
assigning F2 as T's instance constructor or T's subtype instance prototype constructor.

3 more elements

Dependencies are inferred from the claim text.

System supporting object-oriented constructs in ECMAScript

Life of this patent

System supporting object-oriented constructs in ECMAScript

Life of this patent

Abstract

Claims26