[antlr-interest] Nondeterminism and syntantic/semantic predicates info

[Monty Zukowski]

On Aug 4, 2004, at 1:26 PM, Joan Pujol wrote:

> And it is possible that ANTLR is not enough intelligent and give me
> nondeterminism warnings when the gramar is well determined?

Some nondeterminisms are acceptable, for instance the if/else 
ambiguity.  It truly is non-deterministic.  However, the code that 
ANTLR generates handles it the way you would expect.  Being 
nondeterministic means that ANTLR can't predict which alternative to 
choose because of overlapping lookahead sets.

You could give Ter's PhD Thesis a read (on antlr.org,) it sure gives a 
lot of detail on lookahead computations.

Inspecting the code is the best bet.  If you can tell that it will do 
the right thing then you can ignore the warning.

Monty

ANTLR & Java Consultant -- http://www.codetransform.com
ANSI C/GCC transformation toolkit -- 
http://www.codetransform.com/gcc.html
Embrace the Decay -- http://www.codetransform.com/EmbraceDecay.html



 
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