handler_map

like AnyMap, but with functions instead of values

This crate began with an idle thought: "Crates like AnyMap let you store one value of each type. What would it take to instead store a function that took that type, like a message handler?" What came out was this.

The basic idea is that you start with a message type, and a function that receives it by-value:

struct MyMessage;
fn handle_msg(_: MyMessage) {
    println!("Got your message!");
}

Then, take one of these HandlerMaps, and hand it the handler:

let mut map = HandlerMap::new();
map.insert(handle_msg);

This registers that type in the handler so you can call it later:

map.call(MyMessage);

// console prints "Got your message!"