Macro def_impls 

def_impls!() { /* proc-macro */ }

defines enums, with the syntax support of

1. generates a range of enums in the syntax of Enum![ range ]

2. implements traits for enums the variants of which have implemented

Example

The macro below generates enum type Enum1, Enum2 Enum3 with 1,2,3 variants of generic types respectively. The optional impl blocks implement Clone and Display for these enum types.

def_impls! {
    #[derive( Debug, PartialEq )] pub enum Enum[ 1..=3 ] where _Variants!(): Clone;

    impl Clone for Enum!(1..=3) where _Variants!(): Clone {
        fn clone( &self ) -> Self {
            _match!( _enum!( _variant!().clone() ))
        }
    }

    impl Display for Enum!(1..=3) where _Variants!(): Display {
        fn fmt( &self, f: &mut std::fmt::Formatter ) -> std::fmt::Result {
            _match!( _variant!().fmt(f) )
        }
    }
}