Template:ASSTCATEGORY/parent cat
Book:
This subtemplate of {{ASSTCATEGORY}} names the general category, if any, associated with the parent of a local assistant. Meant to be used at option by other templates, not just by {{ASSTCATEGORY}} and its subtemplates.
Usage
Pass the name of the parent page as unnamed parameter. The result is blank if the parent page has no associated general category. If provided, the result omits the Category: prefix.
Internals
This subtemplate is meant to be customized for different projects.
If this subtemplate returns non-blank, it has, at this writing, two effects on the local assistant category: renaming it (per {{ASSTCATEGORY}}), and making it a subcategory of the parent category (per {{AssistantCat}}).
For example, as of this writing, on English Wikibooks all the pages associated with a book Transdimensional Engineering would be arranged under Category:Book:Transdimensional Engineering. So an assistant Transdimensional Engineering/Assistant:Console would have associated Category:Book:Transdimensional Engineering/Assistant:Console (rather than the same without the Book: prefix), and the assistant category would itself belong to the book category (as well as to Category:Interactive assistants).
Customizations should prefix any template calls or magic words with safesubst:<noinclude/>, so the subtemplate can be substituted as well as transcluded.