Up to Design Issues Principles of Design Again and again we fall back on the folklore of the principles of good design. Sometimes I need a URI for them so this is started as collection of them. I have written about some in many places. The third pair of ideas I have found commonly useful for the Web. I mentioned them in a keynote at WWW7 and the note on Evolvability .
Simplicity is easily to quote but often ignored in strange ways.
Perhaps this is because it is the eye of the beholder. A language which uses fewer basic elements to achieve the same power is simpler. They look simple, just an extra sort of thing in the language, but the complicate what was a very clean design of elements and attributes, and a complication in the underlying syntax is has great effect. All specifications which refer to XML processing will have to figure out what to do about processing instructions as well as elements. When you design a system, or a langauge, then if the features can be broken into relatively loosely bound groups of relatively closely bound features, then that division is a good thing to be made a part of the design.