implemented!

doc/todo/matching_different_kinds_of_links.mdwn

@@ -36,6 +36,11 @@ Besides pagespecs, the `rel=` attribute could be used for styles. --Ivan Z.
 > 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>
@@ -45,3 +50,49 @@ I saw somewhere else here some suggestions for the wiki-syntax for specifying th
 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]]).