Re: Re: software design clarification

> What reasons are there against XML in the specific case of ASTs?

I would ask why do you want to use the extensible markup language for 
processing of abstract syntax trees.
It won't be required if the trees are internally created and only 
analysed be the same program. It may be convenient to be able to reuse 
the available tools and software libraries for this data format.

Clear interfaces between the involved processes are more important for 
safe data exchange.

Regards,
Markus