Implement "Fragment" syntax for html! macro

[wldcordeiro]

It'd be great if you could do something like the Fragment syntax from React in the macro to avoid wrapping things in unnecessary divs.

fn view(model: &Model) -> Html<Msg> {
    html! {
        <>
            <section class="todoapp",>
               ...
            </section>
            <footer class="info",>
                ...
            </footer>
        </>
    }
}

[therustmonk]

Useful thing! 👍 I need to think how to implement it.

[remexre]

Would it also make sense (at least in the short term) to allow the html! macro to expand to either Html<Msg> or Vec<Html<Msg>>, depending on whether one or multiple DOM trees are present?

[wldcordeiro]

@remexre I think fragments would be the equivalent of Vec<Html<Msg>> if I'm interpreting what React does into Rust properly. It's essentially a way to wrap up an array/vector of components/elements.

[remexre]

Sure, but there'd still be the matter of whether html! expands by:

• Always Html<Msg>, change VNode<Msg> to have a "multiple children" variant
• Sometimes Html<Msg>, sometimes Vec<Html<Msg>>
• Always Vec<Html<Msg>>
• Redefine Html<Msg> = Vec<VNode<Msg>>
• Maybe something like Html<Msg> = ArrayVec<[VNode<Msg>; 1]>, which would mitigate the performance loss in the single-element case of needing a pointer dereference.

[therustmonk]

Solved with #122