rust macro

playground.rs

macro_rules! enum_with_str_representation {
    (enum $enum_name:ident {
        $($variant:ident => $nice_name:expr,)+
    }) => {
        #[derive(Debug, PartialEq, Eq, Clone, Hash)]
        enum $enum_name {
            $($variant),+
        }
        
        impl ::std::fmt::Display for $enum_name {
            fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
                match *self {
                    $($enum_name::$variant => write!(f, $nice_name)),+
                }
            }
        }
        
        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
        struct ParseError;
        
        impl ::std::str::FromStr for $enum_name {
            type Err = ParseError;
        
            fn from_str(s: &str) -> Result<$enum_name, Self::Err> {
                match s {
                    $($nice_name => Ok($enum_name::$variant),)+
                    _ => Err(ParseError),
                }
            }
        }
    }
}

enum_with_str_representation! {
    enum Status {
        Success => "Success",
        NoContent => "No content",
        NotFound => "Not found",
    }
}

fn main() {
    println!("{:?}", Status::Success);
    println!("{:?}", "Not found".parse::<Status>());
    println!("{:?}", "Internal Server Error".parse::<Status>());
    println!("{:?}", "Internal Server Error".parse::<Status>());
}