macro_rules! dyon_fn {
(fn $name:ident () -> $rt:ty $b:block) => { ... };
(fn $name:ident ($($arg:tt : $t:ty),+) -> $rt:ty $b:block) => { ... };
(fn $name:ident () $b:block) => { ... };
(fn $name:ident ($($arg:tt : $t:ty),+) $b:block) => { ... };
}
Used to declare an embedded/external function in Rust
which can be called from Dyon.
For example, see "examples/functions.rs".