[−][src]Crate delegate_attr
Attribute proc-macro to delegate method to a field.
Examples
Delegate impl
block
use delegate_attr::delegate; struct Foo(String); #[delegate(self.0)] impl Foo { fn as_str(&self) -> &str; fn into_bytes(self) -> Vec<u8>; } let foo = Foo("hello".to_owned()); assert_eq!(foo.as_str(), "hello"); assert_eq!(foo.into_bytes(), b"hello");
Delegate trait impl
struct Iter(std::vec::IntoIter<u8>); #[delegate(self.0)] impl Iterator for Iter { type Item = u8; fn next(&mut self) -> Option<u8>; fn count(self) -> usize; fn size_hint(&self) -> (usize, Option<usize>); fn last(self) -> Option<u8>; } let iter = Iter(vec![1, 2, 4, 8].into_iter()); assert_eq!(iter.count(), 4); let iter = Iter(vec![1, 2, 4, 8].into_iter()); assert_eq!(iter.last(), Some(8)); let iter = Iter(vec![1, 2, 4, 8].into_iter()); assert_eq!(iter.sum::<u8>(), 15);
With more complicated target
struct Foo<T> { inner: RefCell<Vec<T>>, } #[delegate(self.inner.borrow())] impl<T> Foo<T> { fn len(&self) -> usize; } #[delegate(self.inner.borrow_mut())] impl<T> Foo<T> { fn push(&self, value: T); } #[delegate(self.inner.into_inner())] impl<T> Foo<T> { fn into_boxed_slice(self) -> Box<[T]>; } let foo = Foo { inner: RefCell::new(vec![1]) }; assert_eq!(foo.len(), 1); foo.push(2); assert_eq!(foo.len(), 2); assert_eq!(foo.into_boxed_slice().as_ref(), &[1, 2]);
into
and call
attribute
struct Inner; impl Inner { pub fn method(&self, num: u32) -> u32 { num } } struct Wrapper { inner: Inner } #[delegate(self.inner)] impl Wrapper { // calls method, converts result to u64 #[into] pub fn method(&self, num: u32) -> u64; // calls method, returns () #[call(method)] pub fn method_noreturn(&self, num: u32); }
Delegate single method
struct Foo<T>(Vec<T>); impl<T> Foo<T> { #[delegate(self.0)] fn len(&self) -> usize; } let foo = Foo(vec![1]); assert_eq!(foo.len(), 1);
Attribute Macros
delegate |