[antlr-interest] non-determinism.

[mark kant]

How about the following lexer


protected: 
ALPHA: ('a'..'z'|'A'..'Z')
;
protected:
ALPHA_NUM: ('a'..'z'|'A'..'Z'|'0'..'9')
;
protected:
DIGIT: '0'..'9'
;


NAME: (ALPHA) ((ALPHA) | '_' | '.') )*
;

ID: (ALPHA) ( (ALPHA_NUM) |'_'|'.'|'@')*
;

TOKEN: (ALPHANUM|'_'|'.'|'@'|'%'|';'|'~')+
;

NUMBER: ( DIGITS )+
;


Thanks

Mark
--- mzukowski at yci.com wrote:
> remove your AT rule and then add a literal keyword
> AT='@' to the keywords
> section and test for it in TOKEN by turning on the
> option testLiterals=true.
> See the docs on literals.
> 
> Monty
> 
> -----Original Message-----
> From: mark kant [mailto:markkant2001 at yahoo.com]
> Sent: Tuesday, March 25, 2003 9:42 AM
> To: antlr-interest at yahoogroups.com
> Subject: [antlr-interest] non-determinism.
> 
> 
> Hi,
> 
> I get non-determinism in the following lexer
> (relevant
> portion of parser and lexer)
> 
> hosport: host COLON password
> 
> password: TOKEN
> 
> host: NAME AT TOKEN
> 
> 
> lexer ...............
> 
> COLON: ':'
> 
> SEMI: ';'
> 
> AT: '@'
> 
> TOKEN: ('a'..'z' | 'A'..'Z'
> |'0'..'9'|'.'|':'|';'|'@')+
> 
> 
> What is the best way to resolve it:
> 1. multiple lexers
> 2. syntactic predicates - not appropriate as I have
> other similar rules for special characters
> 3. some kind of flag set in parser and lexer checks
> it
> before matching a rule in lexer (how do I
> communicate
> the flag state from parser to lexer). I have done
> this
> in Lex and YAcc.
> 
> Thanks
> 
> Mark
> 
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