[antlr-interest] comments on suggestion to reduce tree construction code size
Terence Parr
parrt at jguru.com
Fri Dec 28 11:44:46 PST 2001
On Thursday, December 27, 2001, at 06:09 AM, Ric Klaren wrote:
> I would like to look at this before it might go into C++ mode. My
> experience with these kind of guards is that in a non critical loop the
> overhead is usually neglectible. Object creation can be very costly in
> C++.
Okidoki.
> Also it would depend very much on the grammar and the amount of guessing
> occuring. Does this work in the general case?
It depends on how much you use predicates ;)
> It also depends on coding style in antlr. If you spread around a lot of
> actions which could be bundled in one action block, you'll end up with a
> lot of 'guards'.
Well, it only turns gates off of the automatically generated tree
construction stuff as we can say "no side-effects". user actions can
lots of stuff like adding objects to symbol tables.
Ter
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