This document specifies relation types for Web links, and defines a registry for them. It also defines the use of such links in HTTP headers with the Link header-field.

Traits provide a mechanism that can be used to factor out shared behaviour from classes. The purpose of this paper is to provide a formal basis for understanding and reasoning about traits; it is not intended to be self-contained. A companion paper, which we will refer to as the “traits paper” [SDNB02], shows that traits overcome many difficulties with single and multiple inheritance, and with mixins. We have also reported on the use of an experimental implementation to refactor a part of the Smalltalk collections hierarchy [BSD02].

Abstract: The essence of object orientation is that networks of communicating objects work
together to achieve a common goal. Surely, the common sense of object orientated
programming is that we should write code that describes how this works. We have,
unfortunately, chosen differently and code is commonly written in terms of classes. A class tells us everything about the properties of the individual objects that are its instances. It does not say how these instances interact to achieve the system’s behavior nor does it say how they represent the system’s state in the objects and the relations between them.