Currently, the compiler allows this:

while not .is_eof() and .is_numeric() or .get_byte() == b'.' {
  // ...
}

But this is ambiguous as to how the and and or should be resolved. Instead, we should prevent both being part of the same "group", requiring that parentheses are provided to disambiguate it:

// either:
while not .is_eof() and (.is_numeric() or .get_byte() == b'.') {
  // ...
}
// or:
while (not .is_eof() and .is_numeric()) or .get_byte() == b'.' {
  // ...
}