Macro create_enum

macro_rules! create_enum {
    ($name:ident, $(($variant:ident, $value:expr)), *) => { ... };
}

The following macro invocation:

create_enum!(Words, (Pollo, "Pollo"), (Bianco, "Bianco"), (Giallo, "Giallo"));

Turns into a struct where each variant can be turned into and construct from the corresponding string.