Felipe Magno de Almeida wrote:
I guess that would imply to modify the preprocessor's internal state, i.e. causing it to look as if the condition that was actually false had been true. Everything else would potentially lead to inconsistent or undefined behavior.
I think I could keep the last context and define/undefine whatever is needed to make the evaluation true. Then preprocess the two contexts. Shouldnt that do it?
We had a similar discussion already. This involves some kind of re-evaluation of some of the input sequence after changing the internal state of the preprocessor. Wave currently does not support this. Wouldn't this involve making copies of the internal state essentially after every token (or at least before every pp operation), just to ensure it can be restarted at arbitrary points? I'm sure its impossible to make sure not to run into inconsistencies when trying to implement such a scheme (even putting aside the possible performance implications of making state copies). Regards Hartmut