[antlr-interest] Re: Parser performance

[lgcraymer]

--- In antlr-interest at yahoogroups.com, Terence Parr <parrt at c...> wrote:
> 
> On Mar 22, 2004, at 12:06 PM, lgcraymer wrote:
> 
> > On 3.0:
> >
> > Ter's DFA approach will also speed up the parsing engine; 
> > interestingly enough, it may also apply to tree walkers and lead to 
> > k>1
> > support.  AST generation can be significantly optimized (ANTLR 2 does 
> > no optimization), and Ter is starting down a path that could
> > support that--basically, what you would need is a tree generation 
> > (static) analysis pass coupled with some dynamic runtime
> > "analysis" (build an tree constructor instruction stream, and edit it 
> > on the fly before generating code).  Stay tuned.
> 
> Let's be clear to everybody though that this is us thinking out loud as 
> we do research.  No one should expect 3.0 to magically pop up in the 
> near future; i.e., don't wait for 3.0 to use ANTLR.  Use 2.7.3 as 3.0 
> is a nebulous future event.

Perhaps I should have added the caveat.  Ter and I just submitted a seed proposal to NASA--even if ANTLR 3 can be released this 
year, we still can easily lay out a three year research plan that includes significant enhancements.

> note that I will provide a migration tool that auto-converts your 
> grammars to 3.0 where possible. :)

Note that that's a big step up over 2.0:  auto-converting 1.33 grammars that used predicate hoisting, dlg lexers, and so on would have 
been a big task.  Of course, "where possible" is probably not true for tree construction actions, so there will still be some 
disconnects.

--Loring

> Ter
> --
> Professor Comp. Sci., University of San Francisco
> Creator, ANTLR Parser Generator, http://www.antlr.org
> Cofounder, http://www.jguru.com
> Cofounder, http://www.knowspam.net enjoy email again!
> Cofounder, http://www.peerscope.com pure link sharing



 
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