LF macro system

[stustd]

Thinking of software variants and multiple contributors to the same LF project, LF software management could benefit from being able to use a macro system. Initially thinking of implementing something myself, after some digging into the LF parser code I had to conclude that the reading of the imported source files (on which string content the macro system would have to operate) is deeply buried in the eclipse/xtext-based IResourceDescription object -- so it's not a trivial implementation on top the LF parser framework - I have retreated for now ...

However, if it's going to be picked up (sometime) a decision of which macro system technology to use then has to be made. I didn't find any promising Java resources, however ... (personally, I would have opted for LuaX based ypp).

Anyway, just a thought ...