Legostar Galactica

This page explains why PmWiki doesn't currently use hierarchical or nested groups.

Pm's Explanation

When implementing WikiGroups I did think for a while about implementing hierarchical groups but ultimately decided against it for several reasons:

1. It doesn't seem to add any additional power or flexibility
2. It adds complexity in terms of referencing pages in other (sub)groups
3. I examined other systems that implement hierarchical groups and didn't like the complications it seemed to impose

To see the first point, and to borrow from the example given, instead of writing Animal.Mammal.Canine.StBernard one can just as easily write AnimalMammalCanine.StBernard and get basically the same results and capabilities. Or, if we really need separators, perhaps allow hyphens in WikiGroup names and do something like Animal-Mammal-Canine.StBernard.

On the second point, the problem comes from trying to decide what one should do with markup such as "Canine.StBernard" inside of the "Animal.Mammal" group, especially if there's a top-level group named "Canine". If we treat Group.WikiWord links as always being absolute, then there's not much organizational advantage to having hierarchies. If we allow relative paths, then there's all sorts of room for ambiguity unless even more markup is added to resolve it, and it's possible that someone creating a page in an intermediate subgroup inadvertently changes the target of existing links. All of which just makes things more difficult for naive users.

''' Perhaps not the right platform

I would have to agree that for some applications or perhaps for some of us that have a mental construct of hierarchical systems that pmwiki is difficult to wrestle with. I have been searching high and low to figure out how trails, links, and groupings work. I suppose I assumed I could group within groups. The result was that links and pages seemed to disappear. Trails led to places that made no sense and renaming a group disconnected what I thought were children.

Reading this says to me that there are ways to change my thought process about relationships but I think I am too old and set in my ways to rethink all of this and perhaps my best solution is to find another platform. That is not to say the decisions on this platform are not well thought out and work for many (or perhaps most) people.

Does anyone have a suggestion on a platform that would be a good replacement?

History

This topic has been discussed on the pmwiki-users mailing list at great length on several occasions throughout 2003 and 2004, and the general consensus seems to be this:

• The current one-group-level mechanism is seen as the best (or the least bad) of the available choices
• Once a good syntax and semantics for hierarchical groups has been found, we'd like to have it. But we don't want a bad solution here.

The software has been designed such that it could eventually support hierarchical groups via a Cookbook? recipe, if we ever resolve the outstanding issues.

Alternatives

There are also other alternatives to using the group hierarchies to organize page content -- WikiTrails, Categories, and WikiFarms can often resolve the issue with more power and flexibility than what WikiGroups can do.

The Cookbook.SubgroupMarkup? recipe adds one level of subgroup to the current wiki structure. For many problems, this may be sufficient. It introduces [[,subpage]] markup to designate a subpage of the current page. The subpages of a particular page form a subgroup of the current group. For example, [[,proposals]] and [[,discuss]] are pages in the PmWiki.HierarchicalGroups subgroup of the PmWiki group.

Proposals

The issue has been discussed on and off on the mailing list. Summaries of proposals, conceptual backgrounds, and other discussion results can be found on the HierarchicalGroups-Proposals? page.

Category: PmWiki Design