[antlr-interest] help with lexical nondeterminism

[Alan Oursland]

Do you mean "Lexical lookahead and the end-of-token symbol"? That didn't
help me understand why this example doesn't work.

Each of the tokens ends with a ';' and none of them start with a semicolon.
Shouldn't it be clear where the boundaries are?

i.e.
if( LA(1) == '+' ) {
	EXAMPLE1();
}
else if( LA(1) == '.' && LA(2) == '.' ) {
	EXAMPLE1();
}
else if( LA(1) == '.' && LA(2) == ';' ) {
	EXAMPLE2();
}

Alan

> -----Original Message-----
> From: Terence Parr [mailto:parrt at jguru.com]
> Sent: Thursday, February 13, 2003 1:37 AM
> To: antlr-interest at yahoogroups.com
> Subject: Re: [antlr-interest] help with lexical nondeterminism
>
>
> Hi.  Please read the section in the manual about lookahead computations
> that go past the end of a token :)
>
> Ter
>
> On Wednesday, February 12, 2003, at 05:27 PM, Alan Oursland wrote:
>
> > Can anyone explain to me why I am getting the following lexical
> > nondeterminism nondeterminism warning?
> >
> > ANTLR Parser Generator   Version 2.7.2   1989-2003 jGuru.com
> > sample.g: warning:lexical nondeterminism between rules EXAMPLE1 and
> > EXAMPLE2
> > upon
> > sample.g:     k==1:'.'
> > sample.g:     k==2:';'
> > sample.g:     k==3:<end-of-token>
> >
> > =======================================================================
> > =
> > class SampleLexer extends Lexer;
> > options {
> > 	k=3;
> > }
> >
> > EXAMPLE1
> > 	:	"+;"
> > 	|	"..;"
> > 	;
> > EXAMPLE2
> > 	:	".;"
> > 	;
> > =======================================================================
> > =
> >
> > Thank you.
> >
> > Alan
> >
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
> --
> Co-founder, http://www.jguru.com
> Creator, ANTLR Parser Generator: http://www.antlr.org
> Lecturer in Comp. Sci., University of San Francisco
>
>
>
>
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>
>



 

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