Macro tinfo

macro_rules! tinfo {
    ($ty:ty) => { ... };
    ($ty:ty, $name:literal) => { ... };
}

Creates TypeInfo from the given type and reflects whether the type implements Send, Sync, Default, and Clone to the TypeInfo.

If you want your own type name, you can call this macro like tinfo!(T, "new-name").

This macro exploits Rust’s function look-up procedures to determine if the type implements the traits. See TypeHelper for more details.

Examples

use my_ecs::prelude::*;

// - Clone detection

struct A;
struct B;
#[derive(Clone)]
struct C;
#[derive(Clone)]
struct D;

let a = tinfo!(A); // for non-cloneable type A.
let b = tinfo!(B); // for non-cloneable type B.
let c = tinfo!(C); // for cloneable type C.
let d = tinfo!(D); // for cloneable type D.

assert_eq!(a.fn_clone, b.fn_clone); // A and B have the same dummy clone function.
assert_ne!(a.fn_clone, c.fn_clone); // But C has its own clone function.
assert_ne!(a.fn_clone, d.fn_clone); // And so does D.
assert_ne!(c.fn_clone, d.fn_clone);

// - Send & Sync detection

struct SendSync(u8); // Both Send and Sync.
struct NotSendSync(*mut u8); // Neither Send nor Sync.

let send_sync = tinfo!(SendSync);
let not_send_sync = tinfo!(NotSendSync);

assert!(send_sync.is_send);
assert!(send_sync.is_sync);
assert!(!not_send_sync.is_send);
assert!(!not_send_sync.is_sync);

// Incorrect usage

fn is_clone<T: 'static>() -> bool {
    // The macro doesn't work if the type is passed through generic
    // parameter.
    tinfo!(T).is_clone
}

// assert!(is_clone::<C>());