Version resiliency for a host application and custom code

A computer-readable memory storing computer-executable instructions for exposing functionality of objects of a host application executing as unmanaged code to custom code executing as managed code, the instructions comprising:

• an instance of a document-level object of the host application within an application domain of the host application, the object providing an interface that is exposed to managed code;
• an instance of an application-level object of the host application within an application domain of the host application, the object providing an interface that is exposed to managed code;
• an instance of wrapper for the document-level object within an application domain of the custom code runtime, the wrapper providing an interface between the document-level object and custom code;
• and
• a mechanism within the application domain of the custom code runtime for providing to custom code a reference to the application-level object, wherein the custom code can access functionality of the application-level object directly without having to use a wrapper provided by the custom code runtime and wherein when a new version of the host application is released that exposes new functionality through the application-level object, a developer can release custom code that uses the new functionality with a version of the custom code runtime that was already released at the time the new version of the host application was released.

A computing device that exposes functionality of objects of a host application executing as unmanaged code to custom code executing as managed code, comprising:

• a memory storing computer-executable instructions of:
• a host application that includes an instance of a document-level object that provides an interface that is exposed to managed code and an instance of an application-level object that provides an interface that is exposed to managed code;
• and
• a custom code runtime that includes an instance of wrapper for the document-level object within an application domain of the custom code runtime, the wrapper providing an interface between the document-level object and custom code and that provides to custom code a reference to the application-level object, wherein the custom code can access functionality of the application-level object directly without having to use a wrapper provided by the custom code runtime and wherein when a new version of the host application is released that exposes new functionality through the application-level object, a developer can release custom code that uses the new functionality with a version of the custom code runtime that was already released at the time the new version of the host application was released;
• and
• a processor that executes the computer-executable instructions stored in the memory.