Code Tour

Introduction

This project is an attempt to improve Rust example-based learning approach.

Imagine the following example file:

#[derive(Debug)]
struct S {
    x: i32,
    y: i32,
}

fn main() {
    // Declare something.
    // Because it's an example.
    let a = S { x: 7, y: 42 };

    let b = a.x + a.y;

    // Here is the result!
    let c = b + 1;
}

When one runs the example with cargo run --example foo, nothing is printed! It means the author of the example must add println! or dbg! instructions everytime. Moreover the users are going to miss the comments, that's really unfortunate.

Enter code_tour.

Let's rewrite the example as such:

use code_tour::code_tour;

#[derive(Debug)]
struct S {
    x: i32,
    y: i32,
}

#[code_tour]
fn main() {
    /// Declare something.
    /// Because it's an example.
    let a = S { x: 7, y: 42 };

    let b = a.x + a.y;

    /// Here is the result!
    let c = b + 1;
}

Let's re-execute the example as previously, and we'll see:

$ cargo run --example foo

The example annotations are replicated on the output during the execution.

An annotation must be a comment of kind /// or /** … */ that introduces a let binding. That's all for the moment!

Interactive mode

Running the example with --features interactive will display a “Press Enter to continue, otherwise Ctrl-C to exit.” message after each step of your code.

$ cargo run --example foo --features interactive

Quiet mode

Running the example with the environment variable CODE_TOUR_QUIET set will turn code-tour silent. Note that it won't disable the interactive mode (which is on purpose).

$ CODE_TOUR_QUIET=1 cargo run --example foo

Better source code display

Running the example with cargo +nightly will generate a better output for the code, by using Span::source_text.

$ cargo +nightly run --example foo

Install

This is a classic Rust project, thus add code_tour to your Cargo.toml file, and that's it.

License

BSD-3-Clause, see LICENSE.md.