An simple enum variant extractor

Can extract a (mutable) reference or turn into a tuple from fields. When variant is different than the expected, return None.

Example

use digenum::DigEnum;
use std::io::Read;

#[derive(DigEnum)]
enum Login<T: Read> {
    Local,
    Stream(T)
    Token([u8; 64]),
    UserAndPasswd(String, String),
}

Maps to:

Variant	Reference	Mutable Reference	Owned
Local	None	None	None
Stream(T)	as_Stream -> Option<&T>	as_mut_Stream -> Option<&mut T>	into_Stream -> Option<T>
Token([u8; 64])	as_Token -> Option<&[u8; 64]>	as_mut_Token -> Option<&mut [u8; 64]>	into_Token -> Option<[u8; 64]>
UserAndPasswd(String, String)	as_UserAndPasswd -> Option<(&String, &String)>	as_mut_UserAndPasswd -> Option<(&mut String, &mut String)>	into_UserAndPasswd -> Option<(String, String)>

"Why do not turn snake_case?"

Consider this example:

use digenum::DigEnum;

#[derive(DigEnum)]
enum Foo {
    FOO,
    foo,
    Foo
}

How should I handle it?

Works on

• Empty enums
• Empty variants
• Single-fielded variants
• Multiple-fielded variants
• Different-case variants (like Foo::FOO and Foo::foo)
• Generic variants
• Unit variants
• Struct-like variants