Crate tryvial

A small crate for Ok-wrapping and try blocks. This is compatible with Result, Option, and any type implementing the unstable std::ops::Try trait.

This crate does not require nightly Rust.

Overview

The macro try_fn is used to perform Ok-wrapping on the return value of a function.

Before:

fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Enter your name: ");
    let mut name = String::new();
    std::io::stdin().read_line(&mut name)?;
    println!("Hello, {name}!");
    Ok(()) // this is ugly
}

After:

#[try_fn]
fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Enter your name: ");
    let mut name = String::new();
    std::io::stdin().read_line(&mut name)?;
    println!("Hello, {name}!");
}

---

The macro try_block is an implementation of “try blocks” from nightly rust.

let result: Result<T, E> = try_block! {
   let a = do_one(x)?;
   let b = do_two(a)?;
   b
};

---

The macro wrap_ok simply wraps an expression with the “ok” variant for a given Try type.

assert_eq!(Some(42), wrap_ok!(42));

Macros

try_block

Macro for the receiving end of a ? operation.

wrap_ok

Performs “Ok-wrapping” on the result of an expression. This is compatible with Result, Option, [ControlFlow], and any type that implements the unstable [std::ops::Try] trait.

Attribute Macros

try_fn

An attribute macro that performs “Ok-wrapping” on the return value of a fn item. This is compatible with Result, Option, ControlFlow, and any type that implements the unstable [std::ops::Try] trait.

tryvial