4 releases
0.1.3 | Jul 30, 2024 |
---|---|
0.1.2 | Jul 11, 2024 |
0.1.1 | May 3, 2023 |
0.1.0 | May 3, 2023 |
#1689 in Procedural macros
2,311 downloads per month
Used in 3 crates
(via kernel_guard)
11KB
161 lines
crate_interface
Provides a way to define an interface (trait) in a crate, but can implement or use it in any crate. It 's usually used to solve the problem of circular dependencies between crates.
Example
// Define the interface
#[crate_interface::def_interface]
pub trait HelloIf {
fn hello(&self, name: &str, id: usize) -> String;
}
// Implement the interface in any crate
struct HelloIfImpl;
#[crate_interface::impl_interface]
impl HelloIf for HelloIfImpl {
fn hello(&self, name: &str, id: usize) -> String {
format!("Hello, {} {}!", name, id)
}
}
// Call `HelloIfImpl::hello` in any crate
use crate_interface::call_interface;
assert_eq!(
call_interface!(HelloIf::hello("world", 123)),
"Hello, world 123!"
);
assert_eq!(
call_interface!(HelloIf::hello, "rust", 456), // another calling style
"Hello, rust 456!"
);
Implementation
The procedural macros in the above example will generate the following code:
// #[def_interface]
pub trait HelloIf {
fn hello(&self, name: &str, id: usize) -> String;
}
#[allow(non_snake_case)]
pub mod __HelloIf_mod {
use super::*;
extern "Rust" {
pub fn __HelloIf_hello(name: &str, id: usize) -> String;
}
}
struct HelloIfImpl;
// #[impl_interface]
impl HelloIf for HelloIfImpl {
fn hello(&self, name: &str, id: usize) -> String {
{
#[export_name = "__HelloIf_hello"]
extern "Rust" fn __HelloIf_hello(name: &str, id: usize) -> String {
let _impl: HelloIfImpl = HelloIfImpl;
_impl.hello(name, id)
}
}
{
format!("Hello, {} {}!", name, id)
}
}
}
// call_interface!
assert_eq!(
unsafe { __HelloIf_mod::__HelloIf_hello("world", 123) },
"Hello, world 123!"
);
Dependencies
~230–670KB
~16K SLoC