[antlr-interest] Alternative(s) 2 were disabled for that input

[Gavin Lambert]

At 07:32 20/09/2008, jack zhang wrote:
>Thanks. Now the warnings are cleared.  The only issue I had is 
>that for the following invalid inputs, it won't report error. 
>Here is the grammar.
>1) AND
>2) OR
>3) AND a
>4) OR a
[...]
>expr: orexpression*;

Your top level rule does not require anything at all to be matched 
("*" is zero-or-more, and if the input isn't a valid orexpression 
then it'll simply match nothing at all and succeed).

If you want to require at least one orexpression to be present, 
change the * to a +.  If you want to additionally ensure that the 
entire input is consumed (or produce an error if not), add EOF to 
the end of the rule.  For example:

expr : orexpression+ EOF;