bp3d_util/

extension.rs

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//! Helper macro for writing extensions to any foreign type using sealed traits.

/// Generate a sealed trait with a given name and content.
#[macro_export]
macro_rules! extension {
    (
        $(#[$meta: meta])*
        pub extension $name: ident $(<$($generic: ident),*>)?: $ty: ident$(<$($generic1: ident),*>)? {
            $($tokens: tt)*
        }
    ) => {
        mod sealing {
            pub trait Sealed {}
        }
        impl$(<$($generic1),*>)? sealing::Sealed for $ty $(<$($generic1),*>)? {}

        $(#[$meta])*
        pub trait $name $(<$($generic),*>)? : sealing::Sealed {
            $($tokens)*
        }
    };
}