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J_Shelby_J • yesterday at 6:52 PM • 1 reply • view on HN

Wow that’s amazing. The partial equality implementation is really surprising.

One question about avoiding boolean parameters, I’ve just been using structs wrapping bools. But you can’t treat them like bools… you have to index into them like wrapper.0.

Is there a way to treat the enum style replacement for bools like normal bools, or is just done with matches! Or match statements?

It’s probably not too important but if we could treat them like normal bools it’d feel nicer.

Replies

jvanderbot • yesterday at 7:01 PM

I almost always prefer enums and matches! vs bool parameters. Another way is to implement a Trait that you find useful that encapsulates the logic. And don't forget you can do impl <Enum> {} blocks to add useful functions that execute regardless of which member of the enum you got.

    enum MyType{
    
    ...
    
    }

    impl MyType{
        pub fn is_useable_in_this_way(&self) -> bool{
            // possibly ...
            match self {...}
        }
    }
and later:

    pub fn use_in_that_way(e: MyType) {
        if e.is_useable_in_this_way() {...}
    }
Or if you hate all that there's always:

    if let MyType::Member(x) = e {
        ...
    }
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