xilem_web: An example using AnyDomView would be supe... | linebender/xilem

A pull request for this has already been merged.

#460 by @Philipp-M — merged

I'm trying to make a <li> which can have one of two types, either a button or text node, depending on the state.

I tried to do something like:

fn bar(state: &mut bool) -> impl HtmlLiElement<State> {
  html::li(if *state {
    Box::new(html::button("button")) as Box<AnyDomView<State>>
  } else {
    Box::new("not a button") as Box<AnyDomView<State>>
  })
}

But got a bunch of errors:

rustc output

    Checking library-viewer v0.0.0 (/Users/rodarmor/src/gossamer/crates/library-viewer)
error: could not compile `library-viewer` (bin "library-viewer") due to 3 previous errors; 3 warnings emitted
error[E0277]: the trait bound `ViewCtx: OrphanView<&'static str, State, ()>` is not satisfied
   --> crates/library-viewer/src/main.rs:117:5
    |
117 |     Box::new("not a button") as Box<AnyDomView<State>>
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `OrphanView<&'static str, State, ()>` is not implemented for `ViewCtx`, which is required by `&str: AnyView<State, (), ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>>`
    |
    = help: the following other types implement trait `OrphanView<V, State, Action, Message>`:
              <ViewCtx as OrphanView<&'static str, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<BezPath, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<Cow<'static, str>, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<f32, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<f64, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<i16, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<i32, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
              <ViewCtx as OrphanView<i64, State, Action, Box<(dyn xilem_web::Message + 'static)>>>
            and 12 others
    = note: required for `&str` to implement `View<State, (), ViewCtx>`
    = note: required for `&str` to implement `AnyView<State, (), ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>>`
    = note: required for the cast from `Box<&str>` to `Box<(dyn AnyView<State, (), ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>> + 'static)>`

error[E0277]: the trait bound `Box<dyn AnyView<State, (), ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>>>: ViewSequence<_, _, ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>, _, Box<(dyn xilem_web::Message + 'static)>>` is not satisfied
   --> crates/library-viewer/src/main.rs:114:12
    |
114 |     html::li(if *state {
    |  ___--------_^
    | |   |
    | |   required by a bound introduced by this call
115 | |     Box::new(html::button("button")) as Box<AnyDomView<State>>
116 | |   } else {
117 | |     Box::new("not a button") as Box<AnyDomView<State>>
118 | |   })
    | |___^ the trait `ViewSequence<_, _, ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>, _, Box<(dyn xilem_web::Message + 'static)>>` is not implemented for `Box<dyn AnyView<State, (), ViewCtx, Pod<DynNode, Box<(dyn Any + 'static)>>>>`
    |
    = help: the following other types implement trait `ViewSequence<State, Action, Context, Element, Marker, Message>`:
              <() as ViewSequence<State, Action, Context, Element, (), Message>>
              <(Seq,) as ViewSequence<State, Action, Context, Element, (Marker,), Message>>
              <(Seq0, Seq1) as ViewSequence<State, Action, Context, Element, (M0, M1), Message>>
              <(Seq0, Seq1, Seq2) as ViewSequence<State, Action, Context, Element, (M0, M1, M2), Message>>
              <(Seq0, Seq1, Seq2, Seq3) as ViewSequence<State, Action, Context, Element, (M0, M1, M2, M3), Message>>
              <(Seq0, Seq1, Seq2, Seq3, Seq4) as ViewSequence<State, Action, Context, Element, (M0, M1, M2, M3, M4), Message>>
              <(Seq0, Seq1, Seq2, Seq3, Seq4, Seq5) as ViewSequence<State, Action, Context, Element, (M0, M1, M2, M3, M4, M5), Message>>
              <(Seq0, Seq1, Seq2, Seq3, Seq4, Seq5, Seq6) as ViewSequence<State, Action, Context, Element, (M0, M1, M2, M3, M4, M5, M6), Message>>
            and 12 others
note: required by a bound in `xilem_web::elements::html::li`
   --> /Users/rodarmor/src/xilem/xilem_web/src/elements.rs:484:5
    |
484 | /     define_elements!(
485 | |         // the order is copied from
486 | |         // https://developer.mozilla.org/en-US/docs/Web/HTML/Element
487 | |         // DOM interfaces copied from https://html.spec.whatwg.org/multipage/grouping-content....
...   |
516 | |         (Li, li, HtmlLiElement),
    | |              -- required by a bound in this function
...   |
606 | |         (Template, template, HtmlTemplateElement),
607 | |     );
    | |_____^ required by this bound in `li`
    = note: this error originates in the macro `define_element` which comes from the expansion of the macro `define_elements` (in Nightly builds, run with -Z macro-backtrace for more info)

[Finished running. Exit status: 101]

I took a look at the examples, but didn't find any usage of AnyDomView. Am I trying using AnyDomView in the right way here, or is another approach required?

By the way, so far having a lot of fun with xilem_web, so thanks for putting it out there!

Start by reviewing the linked merged pull request #460 and the AnyDomView-related usage in crates/library-viewer/src/main.rs. Check xilem_web/src/elements.rs around the html::li definition and compare with the existing examples; done means providing a working example that demonstrates the button-or-text case and explains whether AnyDomView is appropriate.

Written by the indexing model from the issue text.

xilem_web: An example using AnyDomView would be super helpful

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