enum_primitive::enum_from_primitive!

macro_rules! enum_from_primitive {
    (
        $( #[$enum_attr:meta] )*
        enum $name:ident {
            $( $( #[$variant_attr:meta] )* $variant:ident = $discriminator:expr ),*
        }
    ) => {
        $( #[$enum_attr] )*
        enum $name {
            $( $( #[$variant_attr] )* $variant = $discriminator ),*
        }
        enum_from_primitive_impl! { $name, $($variant),* }
    };

    (
        $( #[$enum_attr:meta] )*
        enum $name:ident {
            $( $( #[$variant_attr:meta] )* $variant:ident = $discriminator:expr ),*,
        }
    ) => {
        enum_from_primitive! {
            $( #[$enum_attr] )*
            enum $name {
                $( $( #[$variant_attr] )* $variant = $discriminator ),*
            }
        }
    };

    (
        $( #[$enum_attr:meta] )*
        pub enum $name:ident {
            $( $( #[$variant_attr:meta] )* $variant:ident = $discriminator:expr ),*
        }
    ) => {
        $( #[$enum_attr] )*
        pub enum $name {
            $( $( #[$variant_attr] )* $variant = $discriminator ),*
        }
        enum_from_primitive_impl! { $name, $( $variant ),* }
    };

    (
        $( #[$enum_attr:meta] )*
        pub enum $name:ident {
            $( $( #[$variant_attr:meta] )* $variant:ident = $discriminator:expr ),*,
        }
    ) => {
        enum_from_primitive! {
            $( #[$enum_attr] )*
            pub enum $name {
                $( $( #[$variant_attr] )* $variant = $discriminator ),*
            }
        }
    };
}

[−] Expand description

Wrap this macro around an enum declaration to get an automatically generated implementation of num::FromPrimitive.