Function thunder::thunderclap

pub fn thunderclap(args: TokenStream, input: TokenStream) -> TokenStream

Main macro that implements automated clap generation. This invokes ✨ magic ✨

Foremost every impl block tagged with the macro will turn into a Thunder-app. At the moment only a single Thunder app can exist in the same scope (this will change).

What a thunder app does is take every function in it's scope and turn it into a CLI handle with clap, meaning that all arguments will be mapped to the user shell as they are described in the function body.

Example

fn say_hello(name: &str, age: Option<u16>) {
    // ...
}

This function will turn into the CLI option say_hello that always takes a name parameter (which is a String) and optionally a number (which has to fit into u16!)

These conversion checks are done at run-time but functions are only called if the parameters are valid. As such, you don't have to worry :)

A more complete example

The block below defines a medium sized thunder application.

struct MyApp;

#[thunderclap]
impl MyApp {
    /// Say hello to someone on the other side
    fn say_hello(name: &str, age: Option<u16>) { /* ... */ }
     
    /// It was nice to meet you!
    fn goodybe(name: Option<&str>) { /* ... */ }
}

fn main() {
    // This starts the match execution
    MyApp::start();
}

## Global variables

It's possible to declare argument parameters that can be invoked on any function and
are available outside of regular context. `thunder` generates an argument store which
you can use to get results from these global arguments.

They can be both mandatory (`T`) or optional (`Option<T>`) and are named and also have
a description displayed to the user. Their names are abbreviated with `--name` and `-n`
if the parameter was called `name`.

A small example below.

```norun
struct MyApp;

#[thunder(arg1: u32: "A small description", arg2: Option<bool>: "Optional global")]
impl MyApp {
    fn hello(name: &str) {}
}

fn main() {
    MyApp::start();
}

If you have more questions or encounter bugs, don't hesitate to contact us! PR's always welcome (we're friendly ❤️)