Avoid %links accumulating duplicates. (For TOVA)

[ikiwiki.git] / doc / plugins / write.mdwn

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 0b358b215a4193efa292d70212eeebf6a14805f4..28da243d5072fdfa6bd3e87d49b33473fd7f6b4c 100644 (file)
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -107,8 +107,8 @@ adding or removing files from it.
 
 This hook is called early in the process of building the wiki, and is used
 as a first pass scan of the page, to collect metadata about the page. It's
 
 This hook is called early in the process of building the wiki, and is used
 as a first pass scan of the page, to collect metadata about the page. It's

-mostly used to scan the page for [[WikiLinks|ikiwiki/WikiLink]], and add them to `%links`.
-Present in IkiWiki 2.40 and later.
+mostly used to scan the page for [[WikiLinks|ikiwiki/WikiLink]], and add
+them to `%links`. Present in IkiWiki 2.40 and later.

 
 The function is passed named parameters "page" and "content". Its return
 value is ignored.
 
 The function is passed named parameters "page" and "content". Its return
 value is ignored.


@@ -151,11 +151,11 @@ parameter is set to a true value if the page is being previewed.
 If `hook` is passed an optional "scan" parameter, set to a true value, this
 makes the hook be called during the preliminary scan that ikiwiki makes of
 updated pages, before begining to render pages. This should be done if the
 If `hook` is passed an optional "scan" parameter, set to a true value, this
 makes the hook be called during the preliminary scan that ikiwiki makes of
 updated pages, before begining to render pages. This should be done if the

-hook modifies data in `%links`. Note that doing so will make the hook be
-run twice per page build, so avoid doing it for expensive hooks. (As an
-optimisation, if your preprocessor hook is called in a void context, you
-can assume it's being run in scan mode, and avoid doing expensive things at
-that point.)
+hook modifies data in `%links` (typically by calling `add_link`). Note that
+doing so will make the hook be run twice per page build, so avoid doing it
+for expensive hooks. (As an optimisation, if your preprocessor hook is
+called in a void context, you can assume it's being run in scan mode, and
+avoid doing expensive things at that point.)

 
 Note that if the [[htmlscrubber]] is enabled, html in
 preprocessor [[ikiwiki/directive]] output is sanitised, which may limit what
 
 Note that if the [[htmlscrubber]] is enabled, html in
 preprocessor [[ikiwiki/directive]] output is sanitised, which may limit what


@@ -174,7 +174,8 @@ links. The function is passed named parameters "page", "destpage", and
 and later.
 
 Plugins that implement linkify must also implement a scan hook, that scans
 and later.
 
 Plugins that implement linkify must also implement a scan hook, that scans

-for the links on the page and adds them to `%links`.
+for the links on the page and adds them to `%links` (typically by calling
+`add_link`).

 
 ### htmlize
 
 
 ### htmlize
 


@@ -753,6 +754,11 @@ Optionally, a third parameter can be passed, to specify the preferred
 filename of the page. For example, `targetpage("foo", "rss", "feed")`
 will yield something like `foo/feed.rss`.
 
 filename of the page. For example, `targetpage("foo", "rss", "feed")`
 will yield something like `foo/feed.rss`.
 

+#### `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.
+

 ## Miscellaneous
 
 ### Internal use pages
 ## Miscellaneous
 
 ### Internal use pages