Re: yacc parse tree

> > get to the top, you have a parse tree. The most annoying part is
> > allocating and deallocating the tree nodes, particularly if you want
> > to recover from parse errors.
>
> I imagine Knuth would have a clever data-structure based solution to this
> one - is anyone aware of any work done on the idea of the parser
> constructing a *tree of trees*?


Once I had done something similar, maybe it suits for you too. you can
get it at


http://www.ug.bcc.bilkent.edu.tr/~scinar/st.tgz


The trick is done in the file yaccp. tree specific functions are in
tnode.c


instead of using the $$ thing, I prefer constructing the tree myself
like this:


when ruleN is reduced,
make a tree whose root is the rule that has just reduced
and children are the children :)
save it to a global variable.


this is done easily by modifiying the output of yacc.


when yyparse() exits, global variable is the root of the whole tree.


****************************************************************************
Sukru Cinar scinar@ug.bcc.bilkent.edu.tr
YetNotGraduate Computer Science Student in Bilkent/Turkey
[Seems to me you're just building your own stack parallel to the one
that yacc already keeps for you. I don't see the advantage of storing
the tree pointer in a global, other than the final top-level tree since
yacc doesn't let you return it from yyparse(). -John]

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