[antlr-interest] [newbie] nondeterminism upon error

[Martin Probst]

Hi,

> Can anyone give me some hints? I don't get why that rule is  
> nondeterministic... If anyone wants to see the whole file I can put  
> it online somewhere.

Can varid be followed by another varid or idrest?

If you have:
varid: SMALL (idrest)*;
idrest: (SMALL | LARGE | ... )*
Then the parser will first consume a SMALL token, then for example  
take another SMALL token, then the parser will be within the idrest  
rule. If now another SMALL token comes up, the parser cannot decide  
whether it should parse the new token as part of the idrest rule  
('alternative 1') or exit the idrest rule and parse it as another  
iteration of the (idrest)* block ('exit branch').

Does this help?

Regards,
Martin