diff options
| -rw-r--r-- | doc/todo/dependency_types.mdwn | 55 |
1 files changed, 53 insertions, 2 deletions
diff --git a/doc/todo/dependency_types.mdwn b/doc/todo/dependency_types.mdwn index d31797f3d..cce5997e8 100644 --- a/doc/todo/dependency_types.mdwn +++ b/doc/todo/dependency_types.mdwn @@ -254,6 +254,14 @@ sigh. >>>> >>>> --[[Will]] +>>>>> I think that should be supported by [[bugs/transitive_dependencies]]. +>>>>> At least in the current implementation, which considers each page +>>>>> that is rendered to be changed, and rebuilds pages that are dependent +>>>>> on it, in a loop. An alternate implementation, which could be faster, +>>>>> is to construct a directed graph and traverse it just once. Sounds +>>>>> like that would probably not support what you want to do. +>>>>> --[[Joey]] + ---- ### Link dependencies @@ -347,6 +355,13 @@ can indirectly influence what pages a pagespec matches. >>> of "!backlink(bogus)" where the page bogus doesn't exist? In this case, the page 'bogus' needs to be in the influence >>> set even though it doesn't exist. >>> +>>>> I think you're right, this is a case that the current code is not +>>>> handling. Actually, I made all the pagespecs return influences +>>>> even if the influence was not present or did not match. But, it +>>>> currently only records influences as dependencies when a pagespec +>>>> successfully matches. Now I'm sure that is wrong, and I've removed +>>>> that false optimisation. I've updated some of the below. --[[Joey]] +>>> >>> Also, I would really like the formalism to include the whole dependency system, not just any additions to it. That will make >>> the whole thing much easier to reason about. >> @@ -364,7 +379,8 @@ can indirectly influence what pages a pagespec matches. #### Examples * The pagespec "created_before(foo)" has an influence list that contains foo. - The removal or (re)creation of foo changes what pages match it. + The removal or (re)creation of foo changes what pages match it. Note that + this is true even if the pagespec currently fails to match. * The pagespec "foo" has an empty influence list. This is because a modification/creation/removal of foo directly changes what the pagespec @@ -377,13 +393,27 @@ can indirectly influence what pages a pagespec matches. >>> So, why don't the above influence lists contain the currently matched pages? >>> Don't you need this to handle the removal problem? -- [[Will]] +>>>> The removal problem is slightly confusingly named, since it does not +>>>> affect pages that were matched by a glob and have been removed. Such +>>>> pages can be handled without being influences, because ikiwiki knows +>>>> they have been removed, and so can still match them against the +>>>> pagespec, and see they used to match; and thus knows that the +>>>> dependency has triggered. +>>>> +>>>> Maybe the thing to do is consider this an optimisation, where such +>>>> pages are influences, but ikiwiki is able to implicitly find them, +>>>> so they do not need to be explicitly stored. --[[Joey]] + * The pagespec "title(foo)" has an influence list that contains every page that currently matches it. A change to any matching page can change its title, making it not match any more, and so the list is needed due to the - removal problem. + removal problem. A page that does not have a matching title is not an + influence, because modifying the page to change its title directly + changes what the pagespec matches. * The pagespec "backlink(index)" has an influence list that contains index (because a change to index changes the backlinks). + Note that this is true even if the backlink currently fails. * The pagespec "link(done)" has an influence list that contains every page that it matches. A change to any matching page can @@ -450,6 +480,27 @@ successful match, we get the right result. > `or` short-circuits too, but the implementation correctly uses `|`, > which I assume is what you meant. --[[smcv]] +>> Er, yeah. --[[Joey]] + +---- + +What about: "!link(done)" + +Specifically, I want to make sure it works now that I've changed +`match_link` to only return a page as an influence if it *does* +link to done. + +So, when matching against page P, that does not link to done, +there are no influences, and the pagespec matches. If P is later +changed to add a link to done, then the dependency resolver will directly +notice that. + +When matching against page P, that does link to done, P +is an influence, and the pagespec does not match. If P is later changed +to not link to done, the influence will do its job. + +Looks good! + #### High-level Calculation and Storage Naively calculating the full influence list for a pagespec requires trying |