allan kelly

There are Patterns, and there are patterns...

or, to put it another way: "When is a Pattern not a pattern?"

I'm not even the best-qualified person to describe this but I'll give it a go - I've said this before so I'll say it again - just remember these are just my views.

The Patterns community has not copyright, trademark or divine right to the word pattern. When I use the word Pattern I'm discussing ideas on form derived from the works of Christopher Alexander, for example:

* A Timeless way of Building, 1979
* A Pattern Language, 1978

Alexander's ideas are rooted in architecture, my interest come from software. Starting in the early 1990's a lot of people in the software development community have become interested in how Alexander's work can be applied to software.

So, when I talk of the "patterns community" I really mean working with ideas of patterns somehow derived from Alexander's work, and specifically those involved with the Hillside Group, Hillside Europe and the conferences organised by these groups (e.g. PLoP, ChilliPLoP, EuroPLoP and VikingPLoP.)

Getting back to Patterns and patterns... I use the term Patterns - capital 'P' - to refer to Alexander derived things. Now, once in a while you come across things the authors call "patterns" and you have to work out whether these are Patterns or just patterns. This simplest test it to look at the references and see if they cite Alexander, if they don't they probably aren't Patterns.

Without a reference to Alexander I usually find the authors aren't aware of the dimensions of context, forces, problem, solutions and consequences. When the author is aware then these things they show. Of course, there are exceptions...