Composition of Meta-objects in Guaran a Composition of Meta-objects in Guaran A

There are meta-object protocols (MOPs) that do not provide support for meta-object composition. Others require explicit modii-cation of existing meta-level code or provide a limited delegation mechanism in order to support it. There is much room for improvement in this eld. The MOP of Guaran a favors the development of meta-objects that can be easily composed. Composers are meta-objects that de-ne arbitrary policies of delegation to other meta-objects, separating the implementation of meta-level functionality from its organization. Composers can also implement meta-level security policies, limiting the abilities of its component meta-objects. Composers can be further composed, forming a potentially innnite reconngurable hierarchy. Our MOP is currently implemented in Java TM. Nevertheless, most design decisions presented in this paper can be transported to other programming languages and MOPs, improving their exibility, reconngurability, security and code reuse.