Re: why are locations dictated by bison?

[Bruce Lilly]

Hans Aberg wrote:
[...]
> Bison reserves the values 0 (initial/end "$") and 1 ("error"), but the
> other non-character tokens have values > 256, so one knows that tokens in
[...]

Bison 1.28 uses 256 for error, not 1.  And it uses -1 for end.
0 is reserved, but one can define a NUL token and return that
from flex via a rule like:

\0  { return NUL; }

Obviously, that rule has to appear before the catch-all rule.