= Support for InterWiki links =

''(since [milestone:0.10])''

== Definition ==

An InterWiki link can be used for referring to a Wiki page
located in another Wiki system, and by extension, to any object
located in any other Web application, provided a simple URL 
mapping can be done.

== Link Syntax ==

{{{
<target_wiki>(:<identifier>)+
}}}

The link is composed by the targeted Wiki (or system) name,
followed by a column (e.g. {{{MeatBall:}}}),
followed by a page specification in the target.
Note that, as for InterTrac prefixes, InterWiki prefixes are case insensitive.

The target Wiki URL is looked up in a the InterMapTxt wiki page, 
modelled after
[http://www.usemod.com/cgi-bin/mb.pl?InterMapTxt MeatBall:InterMapTxt].

In addition to traditional InterWiki links, where the target
is simply ''appended'' to the URL, 
Trac supports parametric InterWiki URLs:
identifiers `$1`, `$2`, ... in the URL
will be replaced by corresponding arguments.
The argument list is formed by splitting the page identifier
using the ":" separator.

== Examples ==

If the following is an excerpt of the InterMapTxt page:

{{{
= InterMapTxt =
== This is the place for defining InterWiki prefixes ==

Currently active prefixes: [[InterWiki]]

This page is modelled after the MeatBall:InterMapTxt page.
In addition, an optional comment is allowed after the mapping.
----
{{{
PEP     http://www.python.org/peps/pep-$1.html                                       # Python Enhancement Proposal $1 
TracML  http://thread.gmane.org/gmane.comp.version-control.subversion.trac.general/$1  # Message $1 in Trac Mailing List

...
MeatBall http://www.usemod.com/cgi-bin/mb.pl?
MetaWiki http://sunir.org/apps/meta.pl?
MetaWikiPedia http://meta.wikipedia.org/wiki/
MoinMoin http://moinmoin.wikiwikiweb.de/
...
}}}
}}}

Then, 
 * `MoinMoin:InterWikiMap` should be rendered as 
   [http://moinmoin.wikiwikiweb.de/InterWikiMap MoinMoin:InterWikiMap]
   and the ''title'' for that link would be "!InterWikiMap in !MoinMoin"
 * {{{TracML:4346}}} should be rendered as 
   [http://thread.gmane.org/gmane.comp.version-control.subversion.trac.general/4346 TracML:4346]
   and the ''title'' for that link would be "Message 4346 in Trac Mailing List"