4 releases

Uses new Rust 2021

0.1.3 Apr 5, 2022
0.1.2 Mar 27, 2022
0.1.1 Mar 27, 2022
0.1.0 Mar 27, 2022

#641 in Rust patterns








Crates.io License

What is sing?

This crate is meant to create interfaces between traits in Rust libraries and the command line. It does this by providing two macros:

  • sing_add_trait, which acts as an attribute to a trait implementation and gathers the method signatures that are used by sing_loop!.
  • sing_loop!, which takes a trait object and serialization/deserialization functions as well as some optional parameters. It generates a loop parsing function calls coming from STDIN (or any other BufRead stream), evaluating them by calling the appropriate method on the object and returning them on STDOUT (or any other Write stream).

Usage example

use serde::{Serialize, Deserialize};
use sing_rs::{sing_add_trait, sing_loop};

trait FruitTree {
         fn shake(&self, shakes: u32) -> Vec<Fruit>;

#[derive(Debug, Serialize, Deserialize)]
struct Fruit {
         fruit_type: String,

struct BananaTree;

impl FruitTree for BananaTree {
         fn shake(&self, shakes: u32) -> Vec<Fruit>{
                  let mut out = vec!();

                  for _ in 0..shakes {
                                out.push(Fruit{fruit_type: String::from("Banana")});

fn main() {
         let tree = BananaTree {};
    sing_loop!(tree, [different, ron::to_string, ron::from_str],);

Negotiator? Really?

Yes, it's somewhat far-fetched, but I really wanted to be able to sing and clap in my rusty command-line projects.

Why the name?

See above.


~251K SLoC