| /// Implement the standard library `Clone` for a trait object that has |
| /// `DynClone` as a supertrait. |
| /// |
| /// ``` |
| /// use dyn_clone::DynClone; |
| /// |
| /// trait MyTrait: DynClone { |
| /// /* ... */ |
| /// } |
| /// |
| /// dyn_clone::clone_trait_object!(MyTrait); |
| /// |
| /// // Now data structures containing Box<dyn MyTrait> can derive Clone. |
| /// #[derive(Clone)] |
| /// struct Container { |
| /// trait_object: Box<dyn MyTrait>, |
| /// } |
| /// ``` |
| /// |
| /// The macro supports traits that have type parameters and/or `where` clauses. |
| /// |
| /// ``` |
| /// use dyn_clone::DynClone; |
| /// use std::io::Read; |
| /// |
| /// trait Difficult<R>: DynClone where R: Read { |
| /// /* ... */ |
| /// } |
| /// |
| /// dyn_clone::clone_trait_object!(<R> Difficult<R> where R: Read); |
| /// ``` |
| #[macro_export] |
| macro_rules! clone_trait_object { |
| ($($path:tt)+) => { |
| $crate::__internal_clone_trait_object!(begin $($path)+); |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __internal_clone_trait_object { |
| // Invocation started with `<`, parse generics. |
| (begin < $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(generics () () $($rest)*); |
| }; |
| |
| // Invocation did not start with `<`. |
| (begin $first:tt $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(path () ($first) $($rest)*); |
| }; |
| |
| // End of generics. |
| (generics ($($generics:tt)*) () > $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(path ($($generics)*) () $($rest)*); |
| }; |
| |
| // Generics open bracket. |
| (generics ($($generics:tt)*) ($($brackets:tt)*) < $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(generics ($($generics)* <) ($($brackets)* <) $($rest)*); |
| }; |
| |
| // Generics close bracket. |
| (generics ($($generics:tt)*) (< $($brackets:tt)*) > $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(generics ($($generics)* >) ($($brackets)*) $($rest)*); |
| }; |
| |
| // Token inside of generics. |
| (generics ($($generics:tt)*) ($($brackets:tt)*) $first:tt $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(generics ($($generics)* $first) ($($brackets)*) $($rest)*); |
| }; |
| |
| // End with `where` clause. |
| (path ($($generics:tt)*) ($($path:tt)*) where $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(impl ($($generics)*) ($($path)*) ($($rest)*)); |
| }; |
| |
| // End without `where` clause. |
| (path ($($generics:tt)*) ($($path:tt)*)) => { |
| $crate::__internal_clone_trait_object!(impl ($($generics)*) ($($path)*) ()); |
| }; |
| |
| // Token inside of path. |
| (path ($($generics:tt)*) ($($path:tt)*) $first:tt $($rest:tt)*) => { |
| $crate::__internal_clone_trait_object!(path ($($generics)*) ($($path)* $first) $($rest)*); |
| }; |
| |
| // The impl. |
| (impl ($($generics:tt)*) ($($path:tt)*) ($($bound:tt)*)) => { |
| impl<'clone, $($generics)*> $crate::private::Clone for $crate::private::Box<dyn $($path)* + 'clone> where $($bound)* { |
| fn clone(&self) -> Self { |
| $crate::clone_box(&**self) |
| } |
| } |
| impl<'clone, $($generics)*> $crate::private::Clone for $crate::private::Box<dyn $($path)* + $crate::private::Send + 'clone> where $($bound)* { |
| fn clone(&self) -> Self { |
| $crate::clone_box(&**self) |
| } |
| } |
| impl<'clone, $($generics)*> $crate::private::Clone for $crate::private::Box<dyn $($path)* + $crate::private::Sync + 'clone> where $($bound)* { |
| fn clone(&self) -> Self { |
| $crate::clone_box(&**self) |
| } |
| } |
| impl<'clone, $($generics)*> $crate::private::Clone for $crate::private::Box<dyn $($path)* + $crate::private::Send + $crate::private::Sync + 'clone> where $($bound)* { |
| fn clone(&self) -> Self { |
| $crate::clone_box(&**self) |
| } |
| } |
| }; |
| } |