If I do this: engine->RegisterObjectType("size_t", sizeof(size_t), asOBJ_PRIMITIVE) Are the normal math operations going to work the same way they would as an int? All I want is a typedef sort of system.

Unfortunately not. You'll have to register all the operators you want to use.

typedefs will be implemented in the future.

You can use a preprocessor (read: mine) and #define size_t uint.