The classic template for a pattern description, in Alexander's *Pattern language*, has these elements: - Distinctive, evocative name - Evocative image
- Context - the patterns that this pattern helps to complete; the elements of the situation in which the pattern becomes needed - Keynote - A summary paragraph, equivalent to the 'reference' of a wiki page. This outlines the challenge, tension or contradiction that the pattern is a practical response to - Siblings - Actually, not in Alexander. These are patterns that resonate with or affiliate with the present pattern, without being (hierarchical) context. Peers, not details, not parents
- Back story - The research, the narratives, the history, the evidence, the precedents, the journalism, the mythology, the disputes. > This can be very substantial - effectively a sub-family of notes, a notebook-within-a-notebook. Organised under a number of categories to constitute a (searchanble) library. Shown on this page, categories of back-story are: concepts, stories, skills, genres (adopted from Cook & Brown's 'generative Dance of knowing')
- Core - The protocol for resolving the tension or contradiction that characterises the pattern. The heart of the pattern, as a piece of practical wisdom - Schema - Highlights the core dynamic or relationship underlying the resolution
- Detail - Patterns that detail this one, assist in completing it
This is very full, and very few pattern languages since Alexander's have had the stick-with-it to develop this kind of texture or depth. It seems important to maintain this level of aspiration.
Some of these elements are essentially narrative, making the pattern 'tellable' as a kind of how-to-solve-it story, and 'weavable' or 'singable' within the dance or the chorus of other patterns. Others are more strictly structural. The structural elements are highlighted in the schema below.
The categories in a pattern description
A further distinction is made between 'structure categories' in the pattern template and 'theme tags' in the back story. Thus, there are two systems of categories implied by a pattern.
The structure categories determine the weave of the pattern among other patterns in the language - and of course, its links with other pattern pages in the wiki.
The theme tags determine the weave of elements in the back story of this pattern, in relation to the back stories of other patterns, within a de facto 'library' of evidence, historical intances, journalism, documented skills, descriptions of genres in communities of practice, analyses of economic and cultural institutional forms; etc.
It would be powerfully helpful, if there were a wiki paragraph (maybe a plugin, maybe just a Graphviz 'snippet') that would generate a pattern graph out of a pattern template, running off its structure categories. A 1up 1down graph visualises a pattern, a 2up 2down graph visualises a small pattern cluster. 3up 3down is perhaps as complex as a mind might want to contemplate on a page.
Michael Mehaffy's npl pattern language probably has means of dealing with this visualisation challenge, but we haven't checked these out yet in the present context. New pattern language - Growing regions
David Bovill has a 'See also' plugin which graphs the pages linked following a 'See also' heading. this seems halfway to doing the work outlined above, in connection with the four structure categories in a pattern description - it would just involve picking up four headings on the page? However I can't find that plugin right now 🙁
It also would be powerfully helpful if there were a paragraph that generates a library 'handbook' - constituting a distinct wiki or wiki-within-wiki - out of the back-stories of the patterns in a language wiki, organised (for example) on its theme tags. Nested categories in a handbook
The 'nest' tooling and the graph tooling complement each other. A pattern language directly generates a requirement for both.