How to write conditional rules?

[tamlok]

Hi,

I am writing a markdown parser. As what we know, there are some feature extensions to the standard markdown grammar. So I want to provide some macros as switches and only compile a certain rules based on the switch.

One solution might be evaluating a C code expression as a precondition check.

I am trying to rewrite the PEG parser here in PackCC and it has the ability to use a C code expression as a precondition check: https://github.com/vnotex/peg-markdown-highlight/blob/20f17c03969a1655c39536bf78f3ee5c2a9dd9f7/pmh_grammar.leg#L97

What is the right way to do it in PackCC?

Thanks!

[arithy]

Hello @tamlok , sorry for the late reply.
Currently, PackCC cannot provide a suitable solution. I recognize it's a big issue considering the indent-based grammar such as Markdown and Python (#79). I'm now developing a new feature to solve this. It may take a few months to release it.

[tamlok]

Hi @arithy , great to hear from you again!!! I am now all in the packcc in my project :)

Thanks for your work! Look forward to it.