X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/0e82950125d9f6182689cf74921dbb57f1140f96..de62ea1cc8111dd96bc84b9c839be99c921168e3:/doc/todo/matching_different_kinds_of_links.mdwn

diff --git a/doc/todo/matching_different_kinds_of_links.mdwn b/doc/todo/matching_different_kinds_of_links.mdwn
index d3c3a1375..20acdde49 100644
--- a/doc/todo/matching_different_kinds_of_links.mdwn
+++ b/doc/todo/matching_different_kinds_of_links.mdwn
@@ -7,3 +7,111 @@ And in general, it would be quite useful to be able to distinguish different kin
 It could distinguish the links by the `rel=` attribute. ([[Tags already receive a special rel-class|todo/rel_attribute_for_links]].) This means there is a general need for a syntax to specify user-defined rel-classes on wikilink (then bug deps would simply use their special rel-class, either directly, or through a special directive like `\[[!depends ]]`), and to refer to them in pagespecs (in forward and backward direction).
 
 Besides pagespecs, the `rel=` attribute could be used for styles. --Ivan Z.
+
+> FWIW, the `add_link` function introduced in a recent
+> release adds an abstraction that could be used to get
+> part of the way there to storing data about different types of
+> links. That function could easily be extended to take an optional
+> third parameter specifying the link type.
+> 
+> Then there's the question of how to store and access the data. `%links`
+> does not offer a good way to add additional information about links.
+> Now, we could toss `%links` entirely and switch to an accessor function,
+> but let's think about not doing that..
+> 
+> The data that seems to be needed is basically a deep hash, so
+> one could check `$linktype{$page}{tag}{$link}` to see if
+> the page contains a link of the given type. (Note that pages could
+> contain links that were duplicates except for their types.)
+> 
+> There would be some data duplication, unfortuantly, but if `%linktype`
+> is not populated for regular wikilinks, it would at least be limited to
+> tags and other unusual link types, so not too bad.
+> 
+> `%linktype` could be stored in `%pagestate`.. if so
+> the actual use might look like `$pagestate{$page}{linktype}{tag}{$link}`.
+> That could be implemented by the tag plugin right now
+> with no core changes. (BTW, then I originally wrote tag, pagestate
+> was not available, which is why I didn't make it differentiate from
+> normal links.) Might be better to go ahead and add the variable to
+> core though. --[[Joey]] 
+
+>> I've implemented this with the data structure you suggested, except that
+>> I called it `%typedlinks` instead of `%linktype` (it seemed to make more
+>> sense that way). I also ported `tag` to it, and added a `tagged_is_strict`
+>> config option. See below! --[[smcv]]
+
+I saw somewhere else here some suggestions for the wiki-syntax for specifying the relation name of a link. One more suggestion---[the syntax used in Semantic MediaWiki](http://en.wikipedia.org/wiki/Semantic_MediaWiki#Basic_usage), like this:
+
+<pre>
+... the capital city is \[[Has capital::Berlin]] ...
+</pre>
+
+So a part of the effect of [[`\[[!taglink TAG\]\]`|plugins/tag]] could be represented as something like `\[[tag::TAG]]` or (more understandable relation name in what concerns the direction) `\[[tagged::TAG]]`.
+
+I don't have any opinion on this syntax (whether it's good or not)...--Ivan Z.
+
+-------
+
+>> [[!template id=gitbranch author="[[Simon_McVittie|smcv]]" branch=smcv/link-types]]
+>> [[!tag patch]]
+
+## Documentation for smcv's branch
+
+### added to [[ikiwiki/pagespec]]
+
+* "`typedlink(type glob)`" - matches pages that link to a given page (or glob)
+  with a given link type. Plugins can create links with a specific type:
+  for instance, the tag plugin creates links of type `tag`.
+
+### added to [[plugins/tag]]
+
+If the `tagged_is_strict` config option is set, `tagged()` will only match
+tags explicitly set with [[ikiwiki/directive/tag]] or
+[[ikiwiki/directive/taglink]]; if not (the default), it will also match
+any other [[WikiLinks|ikiwiki/WikiLink]] to the tag page.
+
+### added to [[plugins/write]]
+
+#### `%typedlinks`
+
+The `%typedlinks` hash records links of specific types. Do not modify this
+hash directly; call `add_link()`. The keys are page names, and the values
+are hash references. In each page's hash reference, the keys are link types
+defined by plugins, and the values are hash references with link targets
+as keys, and 1 as a dummy value, something like this:
+
+	$typedlinks{"foo"} = {
+		tag => { short_word => 1, metasyntactic_variable => 1 },
+		next_page => { bar => 1 },
+	};
+
+Ordinary [[WikiLinks|ikiwiki/WikiLink]] appear in `%links`, but not in
+`%typedlinks`.
+
+#### `add_link($$;$)`
+ 
+ This adds a link to `%links`, ensuring that duplicate links are not
+ added. Pass it the page that contains the link, and the link text.
+ 
+An optional third parameter sets the link type (`undef` produces an ordinary
+[[ikiwiki/WikiLink]]).
+
+> Some code refers to `oldtypedlinks`, and other to `oldlinktypes`.
+> 
+> I'm curious what your reasoning was for adding a new variable
+> rather than using `pagestate`. Was it only because you needed
+> the `old` version to detect change, or was there other complexity?
+> 
+> I have not convinced myself this is a real problem, but..
+> If a page has a typed link, there seems to be no way to tell
+> if it also has a separate, regular link. `add_link` will add
+> to `@links` when adding a typed, or untyped link. If only untyped
+> links were recorded there, one could tell the difference. But then
+> typed links would not show up at all in eg, a linkmap,
+> unless it was changed to check for typed links too.
+> (Or, regular links could be recorded in typedlinks too,
+> with a empty type. (Bloaty.))
+> 
+> I suspect we could get away without having `tagged_is_strict`
+> without too much transitional trouble. --[[Joey]]