#cpp #compiler #standard #token #preprocessor #macro #c-20

yanked rcpp

An attempt to implement the C++20 standard. This is mostly to have fun & learn rust

0.1.3 Sep 30, 2022
0.1.2 Sep 30, 2022
0.1.1 Sep 26, 2022
0.1.0 Sep 26, 2022

#118 in #preprocessor

GPL-3.0-or-later

2MB
5K SLoC

Contains (JAR file, 2.5MB) antlr4-4.8-2-SNAPSHOT-complete.jar

C++20 preprocessor of C++ written in Rust

Currently, a custom build of lalrpop is needed. I'll find a proper solution to this, or replace it with antlr, which is now supported.

This is a very simple and most certainly wrong preprocessor for C++. This was not done with any major intents, it was simply to test Rust and its capabilities (I find learning by doing a lot more useful than just following tutorials).

As a rust novice, I do not claim this to be of any quality.

So far, the most rellevant missing things are:

  • Module tokens are not implemented in any way. I'm waiting to getting some field experience before even looking at implementing it.
  • String literal rule is way too lax. This is due to the limitations of the regex engine logos uses (Although I could revalidate the string in a following action. So, still a TODO). This does not cause a missclasification of token, so it's ok.
  • the #line directive is not supported (and probably won't for some time, I do not intend to support generated code for now :) )
  • QOL Features of preprocessors, like any pragma directive (none mandated by standard, but #pragma once is expected from any sensible implementation), or the __FUNCTION__ macro (which requires the step 7 parser to be implemented in order to know such information)
  • Most test macros are kinda useless right now. __has_cpp_attribute is literally just hardcoded to 0

I'd say that the first 4 steps of the compilation process of C++ are done-ish! Time for lexing.

If you want more logs on what's going on, you can use the environment varaible RUST_LOG, like so: RUST_LOG=debug

Dependencies

~10–20MB
~237K SLoC