diff options
Diffstat (limited to 'doc/todo')
-rw-r--r-- | doc/todo/dependency_types.mdwn | 59 |
1 files changed, 57 insertions, 2 deletions
diff --git a/doc/todo/dependency_types.mdwn b/doc/todo/dependency_types.mdwn index 0503b47af..7714f2891 100644 --- a/doc/todo/dependency_types.mdwn +++ b/doc/todo/dependency_types.mdwn @@ -170,6 +170,11 @@ I added an "add_depends_spec()" function that adds a dependency on the pagespec changes, then the dependent page is rebuilt. At the moment the implementation uses the same hack used by map and inline - just add all the pages that currently exist as traditional content dependencies. +> As I note below, a problem with this approach is that it has to try +> matching the pagespec against every page, redundantly with the work done +> by the plugin. (But there are ways to avoid that redundant matching.) +> --[[Joey]] + Getting back to commenting on your proposal: Just talking about the definition of a "presence dependency" for the moment, and ignoring implementation. Is a @@ -180,6 +185,11 @@ after `test_page`. `new_page` will not match the spec. Now we'll delete and th `new_page` will match the spec, and yet `new_page` itself hasn't changed. Nor has its 'presence' - it was present before and it is present now. Should this cause a re-build of any page that has a 'presence' dependency on the spec? +> Yes, a presence dep will trigger when a page is added, or removed. + +> Your example is valid.. but it's also not handled right by normal, +> (content) dependencies, for the same reasons. --[[Joey]] + I think that is another version of the problem you encountered with meta-data. In the longer term I was thinking we'd have to introduce a concept of 'internal pagespec dependencies'. Note that I'm @@ -217,6 +227,19 @@ sigh. -- [[Will]] +> I have also been thinking about some sort of analysis pass over pagespecs +> to determine what metadata, pages, etc they depend on. It is indeed +> tricky to do. Even if it's just limited to returning a list of pages +> as you suggest. +> +> Consider: For a `*` glob, it has to return a list of all pages +> in the wiki. Which is expensive. And what if the pagespec is +> something like `* and backlink(index)`? Without analyising the +> boolean relationship between terms, the returned list +> will have many more items in it than it should. Or do we not make +> globs return their matches? (If so we have to deal with those +> with one of the other methods disucssed.) --[[Joey]] + ---- ### Link dependencies @@ -259,9 +282,41 @@ we grew the complication of `depends_simple`. One way to fix this is to include with each dependency, a list of pages that currently match it. If the list changes, the dependency is triggered. -Should be doable, but seems to involve a more work than +Should be doable, but may involve more work than currently. Consider that a dependency on "bugs/*" currently is triggered by just checking until *one* page is found to match it. But to store the list, *every* page would have to be tried against it. Unless the list can somehow be intelligently updated, looking at only the -changed pages. +changed pages. + +---- + +What if there were a function that added a dependency, and at the same time +returned a list of pages matching the pagespec? Plugins that use this would +be exactly the ones, like inline and map, for which this is a problem, and +which already do a match pass over all pages. + +Adding explicit dependencies during this pass would thus be nearly free. +Not 100% free since it would add explicit deps for things that are not +shown on an inline that limits its display to the first sorted N items. +I suppose we could reach 100% free by making the function also handle +sorting and limiting, though that could be overkill. + +---- + +Found a further complication in presence dependencies. Map now uses +presence dependencies when adding its explicit dependencies on pages. But +this defeats the purpose of the explicit dependencies! Because, now, +when B is changed to not match a pagespec, the A's presence dep does +not fire. + +I didn't think things through when switching it to use presense +dependencies there. But, if I change it to use full dependencies, then all +the work that was done to allow map to use presence dependencies for its +main pagespec is for naught. The map will once again have to update +whenever *any* content of the page changes. + +This points toward the conclusion that explicit dependencies, however they +are added, are not the right solution at all. Some other approach, such as +maintaining the list of pages that match a dependency, and noticing when it +changes, is needed. |