[antlr-interest] Problem using predicates in V3

[Terence Parr]

On Feb 11, 2007, at 3:14 AM, Dr. Hartmut Kocher wrote:

> I have a combined grammar that has the normal identifier definition  
> in the lexer.
>
>
>
> fragment DIGIT  :    '0'..'9';
>
>
>
> fragment LETTER :    ('a'..'z'|'A'..'Z');
>
>
>
> INT :    DIGIT+;
>
>
>
> ID   :    ('a'..'z'|'A'..'Z') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')+ ;
>
>
>
> Now I have a keyword ’abc’ that’s used in the parser grammar like so:
>
>
>
> test : ‘abc’ INT?;
>
>
>
> The rule “test” should match input “abc”, “abc 2”, and “abc2”.
>
>
>
> Unfortunately, the latter matches ID as well. Now, I’m trying to  
> force ANTLR to parse “abc2” as two tokens “abc” and INT.

hi.
Then you have an ambiguity.  abc2 matches ID.  Take 0..9 out of ID.

Ter