RFC 2938 (rfc2938) - Page 2 of 18

Identifying Composite Media Features

RFC 2938          Identifying Composite Media Features    September 2000


   9.    Authors' Addresses .........................................15
   10.   Appendix A: The birthday paradox ...........................16
   11.   Full Copyright Statement ...................................18

1. Introduction

   In "A Syntax for Describing Media Feature Sets" [1], an expression
   format is presented for describing media feature capabilities as a
   combination of simple media feature tags [2].

   This document proposes an abbreviated format for a composite media
   feature set, based upon a hash of the feature expression describing
   that composite.

   This memo extends and builds upon the expression syntax described in
   RFC 2533 [1], and it is assumed that the reader is familiar with the
   interpretation of feature set expressions described there.

1.1 Organization of this document

   Section 2 sets out some of the background and goals for feature set
   references.

   Section 3 presents a syntax for feature set references, and describes
   how they are related to feature set expressions.

1.2 Terminology and document conventions

   This section defines a number of terms and other document
   conventions, which are used with specific meaning in this memo.  The
   terms are listed in alphabetical order.

   dereference
            the act of replacing a feature set reference with its
            corresponding feature set expression.  Also called
            "resolution".

   feature set
            some set of media features described by a media feature
            assertion, as described in "A Syntax for Describing Media
            Feature Sets" [1].  (See that memo for a more formal
            definition of this term.)

   feature set expression
            a string that describes some feature set, formulated
            according to the rules in "A Syntax for Describing Media
            feature sets" [1] (and possibly extended by other
            specifications).



Klyne & Masinter            Standards Track