paw
Command line argument paw-rser abstraction for main.
Paw's goal is to show that C's idea of passing arguments into main wasn't that bad at all, but just needed a bit of oxidation to make it work with Rust.
Paw defines a trait, a proc macro, and an example implementation that when combined allow you to pass fully parsed arguments to main. Gone is the need to remember which methods to call in order to parse arguments in the CLI. Instead paw makes command line parsing feel first-class
Examples
More Examples
Installation
Safety
This crate uses #![deny(unsafe_code)]
to ensure everything is implemented in
100% Safe Rust.
Contributing
Want to join us? Check out our "Contributing" guide and take a look at some of these issues:
FAQ
How does paw work?
The paw::main
attribute allows fn main
to take any argument that implements the paw::ParseArgs
trait. paw::ParseArgs
implements one method: parse_args
which returns a Result<Self>
.
Any errors that are generated are returned back from fn main
, and the returned Result
type is in
control of how to print them.
What is the relationship to C?
In C's runtime, arguments command line arguments are passed as a combination of "number of
arguments" (argc
), and a "list of arguments" (argv
):
int
In Rust this would translate to an iterator of arguments, which is what
std::env::Args
provides, which is wrapped in
paw
through paw::Args
.
What's the future for paw?
Paw is an experiment by the CLI WG to provide a better command line experience for everyone. Our
hypothesis is that by moving command line parsing to fn main
Rust's command line experience can
become more intuitive and easy to use.
We hope to gather feedback how this works for people, and see how we can integrate with existing libraries. This will take time, and we might change things in the process.
If this experiment proves to be successful, we might move to formalize the features Paw provide into Rust itself through the RFC process. But that's not the case yet, so for now: we hope you enjoy Paw, and we'd love to hear your about your experiences using it!
License
MIT OR Apache-2.0