[antlr-interest] newbie question, nondeterminism, syntactic predicate

[Gatis Avots]

Hello!


This is my first post to this mailing list. So please do not be too harsh if
my question might seem real dumb for somebody. ;)

I have a simplified grammar (see below). Antlr (v 2.7) generates:
***********************************************************
D:\antlr\277rc1\bin\learn.g: warning:lexical nondeterminism between rules
IDENT
and ANY_NUMBER upon
D:\antlr\277rc1\bin\learn.g:     k==1:'-','0'..'9'
D:\antlr\277rc1\bin\learn.g:     k==2:<end-of-token>,'0'..'9'
Press any key to continue . . .
***********************************************************

Questions:
1) Why is that...? Should not the lookahead of k=2 solve this issue?

2) If not the lookahead, then at least the syntactic predicate ( (MINUS
('0'..'9')) => ANY_NUMBER ( {setType(ANY_NUMBER);}) ) ? Right now it seems
there is no difference if I use this syntactic predicate or not.

3) How can I fix this so that lexer returns token of type IDENT (starting
optionally with '-') or token ANY_NUMBER (starting optionally with '-')

Grammar:
***********************************************************
class MyParser extends Parser;
page: ANY_NUMBER | IDENT;
  
class MyLexer extends Lexer;
options {k=2;}  
   
IDENT: 
   (MINUS ('0'..'9')) => ANY_NUMBER ( {setType(ANY_NUMBER);})
   |(MINUS)? ('a'..'z')+
  ;

ANY_NUMBER:
    (MINUS)? ('0'..'9')+
;
 
protected
MINUS       :  '-';
***********************************************************

Any help will be much appreciated, thank you!
 
Kind regards,
Gatis