[antlr-interest] Constructing trees and building forests...
Terence Parr
parrt at cs.usfca.edu
Thu Jul 29 11:24:26 PDT 2004
On Jul 28, 2004, at 10:43 PM, iank at bearcave.com wrote:
>
> Ter,
>
> Thanks for the reply.
>
> I know that I'm in a minority here, but to me the power of ANTLR is
> mainly in parser generation, not tree construction. My views are
> biased by the fact that most of the parsers I've worked on are for
> languages like C, Fortran 90, Verilog or VHDL. In my opinion when
> you are constructing trees for complex languages, you want to create
> you own trees. So I have been largely uninterested in ANTLR's
> automatic tree construction.
I can understand that for sure. I usually do a mix since some stuff is
easy and the AST suffix operators work great.
> This said, my two cents is for an easy to use, easy to understand,
> robust parser generator that makes creating parsers for complex
> languages as easy as possible. Rather than trees I'd rather have
> something that makes it easy to understand why the parser generator
> does not like my grammar.
Yes, i'm working hard on that in my head. First step was to simply
reduce the number of grammars that ANTLR couldn't handle; enter
LL(star). Unfortunately, when you do get an error it's harder to say
how/why/where as the input could be arbitrarily long! I'm thinking
that I will build up a list of objects with all the info and then
people can change the reporting behavior with a simple mechanism (just
walk the list and do something else). I suspect that an IDE will be
really important here. I would like to highlight the paths that are
ambiguous etc...
> From my point of view, trees are secondary. Building trees is not
> that hard. Writing parsers by hand is. So the "juice" provided by
> ANTLR is that it helps with the most difficult part of parser
> construction.
The core engine will most definitely focus on this. Anything else
could perhaps be a "plugin" :)
> Of course it's easy for me to say... Terence, Loring and others are
> doing all the work. Those who write the code get to call the
> shots. And, as always, I deeply appreciate the work that has gone
> into ANTLR.
Thanks, as always, for your support, Ian. :)
Terence
--
CS Professor & Grad Director, 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
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/antlr-interest/
<*> To unsubscribe from this group, send an email to:
antlr-interest-unsubscribe at yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
More information about the antlr-interest
mailing list