[antlr-interest] hooray! got ANTLR 3 to lex java

[Oliver Zeigermann]

Great! Congratulations :)

Oliver


On Fri, 3 Dec 2004 14:17:46 -0800, Terence Parr <parrt at cs.usfca.edu> wrote:
> 
> Howdy,
> 
> A nice little milestone on the way to getting lexing/parsing working
> properly for 3.0.  I just got the Java lexer from java.g to walk
> through a 120k 5000 line java program.  That is to say, ANTLR 3 is able
> to read the java.g lexical spec and generate a program to break up a
> 5000 java program into tokens.  ANTLR generates both 2150 lines of Java
> (for the main lexing functionality) and generates 33k of bytecodes
> directly to implement some cyclic DFAs.
> 
> Note that even though I'm being hideously inefficient by backtracking
> on every token and by using linear searches for DFA edges rather than
> switch-statements, it lexes the 5000 line Java program in .9s on my
> 1Ghz mac laptop versus 1.7s for the 2.7.4 version of ANTLR on the same
> input.  So, once I spend some time to optimize things, it should go
> pretty dog gone fast! :)
> 
> Anyway, if it can do the java lexer, it can do the parser as that is
> much simpler in terms of lookahead DFAs (should be acyclic and LL(2))
> for the most part.  Oh, and the grammar doesn't need any of the
> manually specified syntactic predicates. :)  The DFA thingie just
> builds a little state machine to look ahead.
> 
> Whew! ...was driving me nuts tracking down lookahead errors in
> thousands of lines of generate bytecode ;)
> 
> Ter
> --
> 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!
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
>


 
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