parse tree

[Aurelian Melinte]

hello,

I will soon need to modify a grammar to build a parse tree. As bison does 
not offer such a functionality , I thought it would be nice to put it 
straight into it. At least, I could not find it and I am surprised to be 
the first one to have thought to.

For this, it looks like I need to (among other things):
-force bison to generate numbers for LHS nonterminals, numbers that do not
 overlap with the terminals' ones
-keep a tree node stack in parallel with the shift/reduce one, from which
 I will build the tree

I would appreciate any suggestions :)

a.