Enum Fill 

pub enum Fill<'a> {
    Ready(&'a (dyn Render + Sync)),
    Awaiting(&'a (dyn AsyncRender + Sync)),
}

One slot’s content, and whether producing it suspends.

Two shapes rather than one because there is no way to run a future to completion from inside a synchronous render: an awaiting fill can only be written by a caller that is itself awaiting. Which of the two a fill is, is decided where the markup was written and is not something the component consuming it has to know — <slot/> lowers to Slots::render in a synchronous template and to render_async in an awaiting one, and the second handles both.

Rendering one directly

Render is implemented, so {@render slots.get("footer")} still works — and panics on an awaiting fill, naming the fix, because there is nothing else it could honestly do. Use <slot name="footer"/> instead, which is the form that has an async path. The panic is unreachable from a synchronous template: a fill that awaits makes its whole enclosing template await.

Variants

Ready(&'a (dyn Render + Sync))

Markup that is already there.

Awaiting(&'a (dyn AsyncRender + Sync))

Markup that has to suspend to be produced.

Implementations

impl<'a> Fill<'a>

pub fn render_async<'r>(self, r: &'r mut dyn Renderer) -> RenderFuture<'r>

where 'a: 'r,

Write this fill into r, suspending if it has to.

Not AsyncRender: that trait has a blanket impl over every Render, which this type is — so an impl here would either conflict with it or, worse, resolve to it and take the panicking synchronous path for exactly the fills that needed the other one.

Trait Implementations

impl<'a> Clone for Fill<'a>

fn clone(&self) -> Fill<'a>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Copy for Fill<'a>

impl Render for Fill<'_>

fn render_into(&self, r: &mut dyn Renderer)

Write this content into r, with no slots filled.

fn render_slots(&self, r: &mut dyn Renderer, _slots: Slots<'_>)

Write this content into r, resolving its <slot>s against slots.