There are many alternatives in OO. Emerald/Jade ([Black 86] and [Raj 89]) provides one, where inheritance is replaced with a roughly equivalent form where reuse occurs at a finer degree of granularity - method and instance variables - with subtype polymorphism making up the difference.

CLOS [Kim 89, ch 4] has a looser coupling of methods to classes and doesn't distinguish a receiver, but packages can help make up the difference.

Object Specialization [Sciore 89] is an example of a hybrid approach between delegation and classical systems, where parent classes have an extra level of indirection and inheritance hierarchies are specified on a per object/class basis.   _{Your Comment}