RACC -- Rust Another Compiler-Compiler

A port of the Berkeley YACC parser-generator to Rust

racc is a Rust procedural macro (proc-macro) that allows crates to embed LALR(1) grammars in Rust source code.

How do I use it?

Look at racc/examples/math.rs for a brief example of how to write a grammar.

What do I do for a lexer?

nom is probably your best bet, for now.

But, why??

I've always loved yacc, and I first ported yacc to Rust as a syntax extension, years ago. This project is mostly an exercise in porting things to Rust, and seeing what the results are. If it's useful to anyone, then it's useful, and if it's not -- well, it's just anothere repo, rotting on Github, bothering no one.

Part of the exercise of this port is seeing how C idioms translate into Rust idioms. I find that porting code to Rust almost invariably clarifies the underlying algorithms, because concepts like slices and vectors much more clearly express the intent of an algorithm than C pointers do.

There are better packages out there, so just give up.

Sure, that's fine. Do whatever you want.

These packages do some or all things better than racc:

• https://crates.io/crates/lalrpop - pretty much better in every way
• https://crates.io/crates/nom - good for writing parsers

Limitations

There are lots of limitations and incomplete aspects of this, unfortunately. Finding them is left an exercise to the reader.

Author

RACC was implemented by Arlie Davis arlie.davis@gmail.com. I did this as an experiment in porting a well-known (and useful) tool to Rust. I was also intrigued by Rust's support for procedural macros, and I wanted to see whether I could implement something interesting using procedural macros.

Feedback

Feel free to send me any feedback on RACC to arlie.davis@gmail.com.

lib.rs:

Contains the supporting logic needed for applications that wish to use RACC-generated parsers. There used to be more stuff in racc_runtime, but now there is only a single Error type. Even this might be eliminated and folded into the generated code.