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After realizing (thanks to [[Allow_TITLE_to_include_part_of_the_path_in_addition_to_the_basename]]) that I needed some kind of "parentlinks on steroids", I wrote a new plugin, called pedigree.

This plugin provides a bunch of loops that one can use in his/her HTML::Template's to iterate over all or a subset of a page's parents. Inside these loops, half a dozen variables are made available, in addition to PAGE and URL that are already provided by parentlinks.

Amongst many possibilities, one can e.g. simply use this plugin to give every parent link a different class= attribute, depending either on its depth in the path leading to the current page, or on its distance to it.

The code and documentation (including simple and complex usage examples) are in the 'pedigree' Git branch in this repo:

git://repo.or.cz/ikiwiki/intrigeri.git

Seems there is also a gitweb.

Ok, I'll take a look. BTW, could you allow user joey on repo.or.cz push access to the main ikiwiki repo you set up there? --[[Joey]]

I did not. The main ikiwiki repo on repo.or.cz seems to have been been setup by johannes.schindelin@gmx.de ; mine is what they call a "fork" (but it's not, obviously). -- intrigeri

Any opinions on the idea/design/implementation?

Seems that there should be a more generic way to do PEDIGREE_BUT_ROOT and PEDIGREE_BUT_TWO_OLDEST (also is_second_ancestor, is_grand_mother etc). One way would be to include in PEDIGREE a set of values like depth_1, depth_2, etc. The one corresponding to the absdepth would be true. This would allow a template like this:

<TMPL_LOOP NAME="PEDIGREE">
  <TMPL_IF NAME="depth_1">
    </TMPL_ELSE>
    <TMPL_IF NAME="depth_2">
    </TMPL_ELSE>
      <TMPL_VAR PAGE> /* only showing pages 2 levels deep */
    </TMPL_IF>
  </TMPL_IF>
</TMPL_LOOP>

The only missing information would be reldepth, but in the above example the author of that template knows that it's absdepth - 1 (Things would be a lot nicer if HTML::Template had equality tests!)

Since this would make it more generic and also fix your one documented bug, I can see no reason not to do it. ;-) --[[Joey]]

Thanks for your comments. I'll answer soon. (Grrr, I really need to find a way to edit this wiki offline, every minute online costs bucks to me, my old modem gently weeps, and I hate webbrowsers.) -- intrigeri

Well, I maybe didn't get your idea properly; I may be missing something obvious, but:

  • I don't understand how this would replace is_grand_mother. As a template writer, I don't know, given an absolute array index (and this is the only piece of data your solution gives me), if it will be e.g. the before-last (how do I say this in correct English?) element of an array whose (variable) size is unknown to me.
  • Knowing that reldepth's value is, in a given loop, always equal to absdepth - 1 is of little use to me (as a template writer): how do I use this piece of information programmatically in my templates, if I want all links with reldepth==2 to be given the same style? I guess some bits of Javascript might do the trick, but if it's getting so complicated, I'll just style my parentlinks another way.

In my understanding, your suggestion gives us little more than can already be achieved anyway with HTML::Template's loop_context_vars (i.e. __first__, __last__ and __counter__). The only added bonus is doing custom stuff for an arbitrary element in the loop, chosen by its absolute depth. Please correct me if needed.

(Intermezzo: in the meantime, to suit my personal real-world needs, I added a DISTANCE loop-variable. Quoting the documentation, it's "thedistance, expressed in path elements, from the current page to the current path element; e.g. this is 1 for the current page's mother, 2 for its grand-mother, etc.".)

Anyway, your comments have made me think of other ways to simplify a bit this plugin, which admittedly provides too much overlapping functionality. Bellow is my reasoning.

In one of my own real world examples, my two main use cases are :

  • the "full-blown example" provided in the documentation (i.e. displaying every parent but mother and grand'ma as a group, and giving every of these two last ones their dedicated div);
  • skipping the two oldest parents, and inside what's left, displaying the three youngest parents (i.e. mother, grand'ma and grand'grand'ma), each one with a dedicated style;

Both of these can be achieved by combining PEDIGREE, DISTANCE, and some CSS tricks to hide some parts of the list. IS_MOTHER and IS_GRAND_MOTHER, as well as PEDIGREE_BUT_TWO_OLDEST, would be convenient shortcuts, but I do not formally need them.

So... it seems things can be simplified greatly:

  • I initially added RELDEPTH for completeness, but I'm not sure anyone would use it. Let's give it up.
  • Once RELDEPTH is lost (modulo Git tendencies to preserve history), the known bug is gone as well, and PEDIGREE_BUT_ROOT and PEDIGREE_BUT_TWO_OLDEST are now only convenient shortcuts functions; they could as well disappear, if you prefer to.

It appears then that I'd be personally happy with the single PEDIGREE loop (renamed to PARENTLINKS), providing only PAGE, URL, ABSDEPTH (maybe renamed to DEPTH), and DISTANCE. This would make my templates a bit more complicated to write and read, but would also keep the plugin's code to the bare minimum. Let's say it is my up-to-date proposal. (Well, if the various shortcuts don't really annoy you, I'd be glad to keep them ;)

(I'll try never to rebase this branch, but writing this plugin has been a pretext for me to start learning Git, so...)

To finish with, it seems no plugin bundled with ikiwiki uses the current parentlinks implementation, so one could event think of moving it from the core to this plugin (which should then be enabled by default, since the default templates do use parentlinks ;).

I think that moving parentlinks out to a plugin is a good idea. However, if it's done, I think the plugin should be named parentlinks, and should continue to use the same template variables as are used now, to avoid needing to change custom templates. Pedigree is a quite nice name, but renaming it to parentlinks seems to be the way to go to me. --[[Joey]]

Agreed. -- intrigeri

Just commited a testsuite for this plugin, BTW. It's nearly twice big as the plugin itself, I'm wondering... -- intrigeri