[Potlatch-dev] Splitting map_features.xml into separate files

[Richard Fairhurst]

map_features.xml is currently 3742 lines. That's quite horrible.

I've added support for includes, so we can split it into several files. 
It works like this:

	[...beginning of map_features.xml...]
	<include file="map_features/roads.xml" />
	[...rest of map_features.xml]

and then in roads.xml:

	<featureGroup>
		<feature name="Motorway">
			<category>roads</category>
			<line/>
			<tag k="highway" v="motorway"/>
			<inputSet ref="majorRoad"/>
			<inputSet ref="common"/>
		</feature>
		<feature name="Trunk">
			<category>roads</category>
			<line/>
			<tag k="highway" v="trunk"/>
			<inputSet ref="majorRoad"/>
			<inputSet ref="common"/>
		</feature>
		[...and so on...]
	</featureGroup>

Some stuff to note:

- It's internally assembled into one big XML file before parsing. So you 
can happily refer from an include file to inputSets within the main file.

- The include file must be a well-formed XML document. In other words: a 
single root node. I suggest that the root node is <featureGroup>, 
containing a bunch of <feature>s, and that <inputSet>s and <category>s 
stay in mapfeatures.xml (because they need to be children of <mapFeatures>.

- All filepaths are resolved from the SWF's base path, _not_ the XML 
file's path. So if you include "map_features/roads.xml", and that then 
tries to include a further file, you'll still need to specify 
"map_features/minor_roads.xml"

- resources/ is getting overcrowded and it'd make sense to put all but 
the root map_features.xml into a map_features/ directory.

For anyone who's interested, 
http://trac.openstreetmap.org/browser/applications/editors/potlatch2/net/systemeD/halcyon/NestedXMLLoader.as 
is the code. Looks simple but took me hours largely due to closure 
scoping issues. :(

cheers
Richard