Allow for variable bindings (let statements) inside a template

[ghost]

For example:
@{ let a = bit.source.unwrap(); }

[lambda-fairy]

Can you give me an example of how such a feature would be used?

I've considered it in the past, but held back because I couldn't find a use case for it.

Note that you can declare variables outside the html! block as well.

[ghost]

because some situation e.g. @for n in 1..2 {}.
we want to insert normal rust expression to cache something.

[ghost]

@for n in somethings {
    div {
        @ { // here are any rust normal code.
            let item = n.something.unwrap(); // here item in something is move out, so we cannot unwrap twise.
        }
        h1 { (item.name) }
        a { (item.age) }
    }
}

[lambda-fairy]

Okay, that makes sense -- thanks. I have a feeling we need to go all the way to arbitrary Rust statements to solve your problem though. Maybe just a @let special form would be enough?

I'll need to think about this a bit more.

[ghost]

but maybe this is powerful and smart.

html! {
    @ {
        somefunction(); // I can run any rust code here.
    }
}

[TheNeikos]

I have to say that I didn't need to do this so far, anything that should be run once can be run outside the macro, and the @if let syntax allows for the rest

Note: I'm not trying to argue too hard against it, however it doesn't feel like something that is necessary.

[lambda-fairy]

Implemented in 39602a0. The new @let form is pretty much like @if let, except the pattern cannot fail.

@Sackery I don't want to allow arbitrary Rust statements within a template. If your view logic is complicated enough that you need a whole block for it, then that's a sign that it should be in a separate function altogether.