106 lines
2.2 KiB
Rust
106 lines
2.2 KiB
Rust
fn simple() -> i32 {
|
|
let y = 10;
|
|
let f = |x| x + y;
|
|
f(2)
|
|
}
|
|
|
|
fn crazy_closure() -> (i32, i32, i32) {
|
|
fn inner<T: Copy>(t: T) -> (i32, T, T) {
|
|
struct NonCopy;
|
|
let x = NonCopy;
|
|
|
|
let a = 2;
|
|
let b = 40;
|
|
let f = move |y, z, asdf| {
|
|
drop(x);
|
|
(a + b + y + z, asdf, t)
|
|
};
|
|
f(a, b, t)
|
|
}
|
|
|
|
inner(10)
|
|
}
|
|
|
|
fn closure_arg_adjustment_problem() -> i64 {
|
|
fn once<F: FnOnce(i64)>(f: F) { f(2); }
|
|
let mut y = 1;
|
|
{
|
|
let f = |x| y += x;
|
|
once(f);
|
|
}
|
|
y
|
|
}
|
|
|
|
fn fn_once_closure_with_multiple_args() -> i64 {
|
|
fn once<F: FnOnce(i64, i64) -> i64>(f: F) -> i64 { f(2, 3) }
|
|
let y = 1;
|
|
{
|
|
let f = |x, z| x + y + z;
|
|
once(f)
|
|
}
|
|
}
|
|
|
|
fn boxed(f: Box<dyn FnOnce() -> i32>) -> i32 {
|
|
f()
|
|
}
|
|
|
|
fn fn_item_as_closure_trait_object() {
|
|
fn foo() {}
|
|
let f: &dyn Fn() = &foo;
|
|
f();
|
|
}
|
|
|
|
fn fn_item_with_args_as_closure_trait_object() {
|
|
fn foo(i: i32) {
|
|
assert_eq!(i, 42);
|
|
}
|
|
let f: &dyn Fn(i32) = &foo;
|
|
f(42);
|
|
}
|
|
|
|
fn fn_item_with_multiple_args_as_closure_trait_object() {
|
|
fn foo(i: i32, j: i32) {
|
|
assert_eq!(i, 42);
|
|
assert_eq!(j, 55);
|
|
}
|
|
|
|
fn bar(i: i32, j: i32, k: f32) {
|
|
assert_eq!(i, 42);
|
|
assert_eq!(j, 55);
|
|
assert_eq!(k, 3.14159)
|
|
}
|
|
let f: &dyn Fn(i32, i32) = &foo;
|
|
f(42, 55);
|
|
let f: &dyn Fn(i32, i32, f32) = &bar;
|
|
f(42, 55, 3.14159);
|
|
}
|
|
|
|
fn fn_ptr_as_closure_trait_object() {
|
|
fn foo() {}
|
|
fn bar(u: u32) { assert_eq!(u, 42); }
|
|
fn baa(u: u32, f: f32) {
|
|
assert_eq!(u, 42);
|
|
assert_eq!(f, 3.141);
|
|
}
|
|
let f: &dyn Fn() = &(foo as fn());
|
|
f();
|
|
let f: &dyn Fn(u32) = &(bar as fn(u32));
|
|
f(42);
|
|
let f: &dyn Fn(u32, f32) = &(baa as fn(u32, f32));
|
|
f(42, 3.141);
|
|
}
|
|
|
|
|
|
fn main() {
|
|
assert_eq!(simple(), 12);
|
|
assert_eq!(crazy_closure(), (84, 10, 10));
|
|
assert_eq!(closure_arg_adjustment_problem(), 3);
|
|
assert_eq!(fn_once_closure_with_multiple_args(), 6);
|
|
assert_eq!(boxed(Box::new({let x = 13; move || x})), 13);
|
|
|
|
fn_item_as_closure_trait_object();
|
|
fn_item_with_args_as_closure_trait_object();
|
|
fn_item_with_multiple_args_as_closure_trait_object();
|
|
fn_ptr_as_closure_trait_object();
|
|
}
|