[antlr-interest] Grammar ambiguity

[Johannes Luber]

Hello,

I have been removing grammar ambiguities of my C# grammar, but I've
stumbled over one case where I have no idea how I can solve it.

The situation is basically:

input: token*;

token: real_literal;

real_literal:
   DECIMAL_DIGIT+ '.' DECIMAL_DIGIT+ EXPONENT_PART? REAL_TYPE_SUFFIX?
   ;

ANTLR doesn't if there are two or more DECIMAL_DIGITs after '.', if
those belong to the same real_literal or if they start a second
real_literal (which has a DECIMAL_DIGIT as start token), as ANTLR can
generate an arbitrary number of tokens.

Hmm, writing about this gave me the idea that I could change the second
DECIMAL_DIGIT into another rule like FRACTIONAL_DECIMAL_DIGIT, but then
I'd get probably an non-determinism between FRACTIONAL_DECIMAL_DIGIT and
DECIMAL_DIGIT.

Any ideas?

Best regards,
Johannes Luber