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Purpose of categoriesCategories (also known as "tags") are a way to organize and find related pages. Categories are implemented by default in PmWiki, and in most wikis they don't require any special code or markup, they're just a useful convention. The idea is that every page that falls into a particular subject area should have a link to a shared page containing links to other pages on that subject. These pages are created in the Category group, and thus these subject areas are called "categories". Using categoriesGetting categories to work requires a single step: adding links to each category. A category named Subject is created by adding a link to Category.Subject on any page. When you add the link to a page, the page can be described as being in the category "Subject". There is a special markup for creating these links which makes categories work more smoothly: [[!Subject]] will create a link to Category.Subject. So [[!Subject]] is a kind of shortcut to the page Subject in the category group. A Category.GroupFooter file is included in the PmWiki release that contains the line It is worth noting that rather than using Category.GroupFooter, the pagelist directive can be added to Category.GroupHeader to similar effect; it just depends on whether you'd prefer to have the list of pages appear before or after any text that you add to the individual category pages (which can be edited just like normal pages). Because we use the normal PageList Similarly, there's no requirement that a "category page" has to be in the Category group -- any page can define a "category" of pages that link to it. An administrator can override the default category group name of "Category" by setting the A page author can also link to a category list without adding the linking page to the category by using [[ {Category.Subject$PageUrl} | Subject ]]. This will create a link that looks like [[!Subject]] without adding the linking page to the category listing. RecapSo, by adding the link [[!Subject]] to a page, a link to that page will automatically appear on the page Category.Subject, as long as Category.GroupFooter has been tweaked appropriately. Thus, you can create a page that automatically creates an alphabetized list of all movies discussed on your wiki by creating links to [[!Movies]] on each film's page; the resulting automatic list would be on the page Category.Movies . Category nestingCategories have the potential for even greater usefulness because Film.ShaunOfTheDead [[!Horror]] [[!Comedy]] [[!2003]] Film.InMyFathersDen [[!Drama]] [[!2004]] Film.TheCorporation [[!Documentary]] [[!2003]] Now then, we can create So, what happens when we display Finally, in Category.Category Category.Genre Category.Comedy Film.ShaunOfTheDead Category.Drama Film.InMyFathersDen Category.Documentary Film.TheCorporation Category.Horror Film.ShaunOfTheDead Category.Year Category.2003 Film.ShaunOfTheDead Film.TheCorporation Category.2004 Film.InMyFathersDen Note however that this isn't a "strict" hierarchy--i.e., any page or category can appear simultaneously in multiple categories. For example, Each category page can have content text before the generated list, e.g., to give a generic description of things in the category. (Or it can be empty, which works fine.) It can also contain associations to related categories ("see also" references). For example, in a tourism wiki, the ''bed and breakfast" category might contain a see-also reference to the "self-catering" category. administrators (intermediate) The guts of the category markupAs mentioned, all of the necessary markup features for Categories are enabled by default in current releases of PmWiki 2.0, but here's how they work for those who are interested. The use of the Category group as the repository for all categories is determined by setting the SDV($CategoryGroup,'Category'); Markup('[[!','<links','/\[\[!([^\|\]] ?)\]\]/', "<span class='category'>[[$CategoryGroup/$1]]</span>"); Coming up with good category schemesThe hard part about using categories is choosing a good vocabulary. Site content managers may wish to follow the Guidelines for the establishment and development of monolingual thesauri (ISO 2788-1986) and the Guidelines for the establishment and development of multilingual thesauri (ISO 5964-1985). Questions to think about include:
Or you can just let people use whatever category terms they find meaningful. A vocabulary (or "folksonomy") will emerge over time. Showing a list of categoriesTo show a list of categories we can use a pagelist for the pages in the category group. For instance the following will list pages in the Category group, put it on page Category.Category for convenience, or on any other page: (:pagelist group=Category list=normal fmt=#title:)
But there is a problem: Just adding a category markup to a page will not create a corresponding category page, even though following the link will show the page with a list of pages linking to it! $AutoCreate['/^Category\./'] = array('ctime' => $Now, 'text' => $page['text']);
Change 'Category' to the name of your category group. You can also add more definitions for more category groups, useful if you use a recipe like Cookbook:Tagger which allows multiple category groups. See also EditVariables#AutoCreate < Passwords | Documentation Index | Page lists > This page may have a more recent version on pmwiki.org: PmWiki:Categories, and a talk page: PmWiki:Categories-Talk. |