I have a wish for NativeBoost (which is probably on your list anyway Igor, just wanted to put it out there): function definitions should be able to understand that I want to accept any object of a hierarchy. Here's my use case: self call: #(git_return_t git_object_lookup(LGitCommitExternal * object, git_repository_ptr repo, git_oid_ptr id, git_otype type)) This function takes a pointer to any of LGitCommitExternal, LGitTreeExternal and LGitBlobExternal. The obvious way for me to do this was to create a superclass LGitObjectExternal and use that superclass in the function like so: self call: #(git_return_t git_object_lookup(LGitObjectExternal * object, git_repository_ptr repo, git_oid_ptr id, git_otype type)) But that gives me an error. So for now I can either use a dummy object (like NBExternalObject) and then convert from that or I have to implement the same function thrice in the different object flavors. Being able to use a superclass would just be awesome! Cheers, Max