[mkgmap-dev] Location not working in trunk default style

Mon Nov 28 07:12:08 GMT 2011

On Mon, Nov 28, 2011 at 12:45:30AM +0100, Olaf Hasemann wrote:
>#def and #undef is IMO not so useful at all, cause you allways are able 
>to prevent the execution of a rule by catching the element within 
>another rule given before the rule you want to 'undef'.

You are right, the #undef would merely allow the OSM parser to drop 
uninteresting tags (saving memory). For a relatively rare tag, such as 
power=line, this should not make much difference. For more widely-used 
tags, you would probably be better off omitting the 
include/source/base-style for the tags you are not interested in.

>Allowing an empty element type definition or a keyword 'next' or 
>'abort_element' comparable to the awk script 'next' statement would 
>help much more keeping the style files simple and readable. Example:
>
>highway=residential & mynamespace:not_usable=yes [ next ]

To my knowledge, this has not been implemented. I am not entirely 
convinced of the usefulness. This should be fairly easy to implement, 
basically replace the convertNode(), convertWay() calls with a no-op 
when the keyword is present. The [] stuff is parsed in 
osmstyle/TypeReader.java. Maybe we could simply have a special flag in 
GType that tells to omit the conversion in convertWay(), convertNode() 
and the like?

	Marko