Allow any type to be used as Children (take 2)

examples/function_todomvc/src/state.rs

@@ -42,6 +42,12 @@ impl Filter {
     }
 }
 
+impl Renderable for Filter {
+    fn into_html(self) -> Html {
+        html! {<>{self.to_string()}</>}
+    }
+}
+
 pub enum Action {
     Add(String),
     Edit((usize, String)),

examples/futures/src/markdown.rs

@@ -54,10 +54,12 @@ pub fn render_markdown(src: &str) -> Html {
                     top = pre;
                 } else if let Tag::Table(aligns) = tag {
                     if let Some(top_children) = top.children_mut() {
-                        for r in top_children.iter_mut() {
+                        for r in top_children.to_vlist_mut().iter_mut() {
                             if let VNode::VTag(ref mut vtag) = r {
                                 if let Some(vtag_children) = vtag.children_mut() {
-                                    for (i, c) in vtag_children.iter_mut().enumerate() {
+                                    for (i, c) in
+                                        vtag_children.to_vlist_mut().iter_mut().enumerate()
+                                    {
                                         if let VNode::VTag(ref mut vtag) = c {
                                             match aligns[i] {
                                                 Alignment::None => {}
@@ -73,7 +75,7 @@ pub fn render_markdown(src: &str) -> Html {
                     }
                 } else if let Tag::TableHead = tag {
                     if let Some(top_children) = top.children_mut() {
-                        for c in top_children.iter_mut() {
+                        for c in top_children.to_vlist_mut().iter_mut() {
                             if let VNode::VTag(ref mut vtag) = c {
                                 // TODO
                                 //                            vtag.tag = "th".into();

examples/nested_list/src/main.rs

@@ -8,7 +8,8 @@ use std::fmt;
 use std::ops::Deref;
 use std::rc::Rc;
 
-use yew::html::{Component, ImplicitClone, Scope};
+use yew::html::{ImplicitClone, Scope};
+use yew::prelude::*;
 
 pub struct WeakComponentLink<COMP: Component>(Rc<RefCell<Option<Scope<COMP>>>>);
 
@@ -62,6 +63,18 @@ impl fmt::Display for Hovered {
     }
 }
 
+impl Renderable for Hovered {
+    fn into_html(self) -> yew::Html {
+        html! {<>{self.to_string()}</>}
+    }
+}
+
+impl Renderable for &'_ Hovered {
+    fn into_html(self) -> yew::Html {
+        html! {<>{self.to_string()}</>}
+    }
+}
+
 fn main() {
     wasm_logger::init(wasm_logger::Config::default());
     yew::Renderer::<app::App>::new().render();

examples/timer/src/main.rs

@@ -139,7 +139,7 @@ impl Component for App {
                         { &self.time }
                     </div>
                     <div id="messages">
-                        { for self.messages.iter().map(|message| html! { <p>{ message }</p> }) }
+                        { for self.messages.iter().map(|message| html! { <p>{ *message }</p> }) }
                     </div>
                 </div>
             </>

examples/timer_functional/src/main.rs

@@ -105,7 +105,7 @@ fn App() -> Html {
         .iter()
         .map(|message| {
             key += 1;
-            html! { <p key={ key }>{ message }</p> }
+            html! { <p key={ key }>{ *message }</p> }
         })
         .collect();
 

examples/todomvc/src/state.rs

@@ -1,5 +1,6 @@
 use serde_derive::{Deserialize, Serialize};
 use strum_macros::{Display, EnumIter};
+use yew::prelude::*;
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct State {
@@ -140,3 +141,9 @@ impl Filter {
         }
     }
 }
+
+impl Renderable for Filter {
+    fn into_html(self) -> yew::Html {
+        html! { <>{self.to_string()}</> }
+    }
+}

packages/yew-macro/src/html_tree/html_component.rs

@@ -133,11 +133,7 @@ impl ToTokens for HtmlComponent {
 
         let ty_span = ty.span().resolved_at(Span::call_site());
         let props_ty = quote_spanned!(ty_span=> <#ty as ::yew::html::BaseComponent>::Properties);
-        let children_renderer = if children.is_empty() {
-            None
-        } else {
-            Some(quote! { ::yew::html::ChildrenRenderer::new(#children) })
-        };
+        let children_renderer = children.to_children_renderer_tokens();
         let build_props = props.build_properties_tokens(&props_ty, children_renderer);
         let key = props.special().wrap_key_attr();
         let use_close_tag = close

packages/yew-macro/src/html_tree/html_element.rs

@@ -313,12 +313,7 @@ impl ToTokens for HtmlElement {
 
         // TODO: if none of the children have possibly None expressions or literals as keys, we can
         // compute `VList.fully_keyed` at compile time.
-        let child_list = quote! {
-            ::yew::virtual_dom::VList::with_children(
-                #children,
-                ::std::option::Option::None,
-            )
-        };
+        let children = children.to_vnode_tokens();
 
         tokens.extend(match &name {
             TagName::Lit(dashedname) => {
@@ -370,7 +365,7 @@ impl ToTokens for HtmlElement {
                                     #key,
                                     #attributes,
                                     #listeners,
-                                    #child_list,
+                                    #children,
                                 ),
                             )
                         }
@@ -392,6 +387,8 @@ impl ToTokens for HtmlElement {
                 let expr = &name.expr;
                 let vtag_name = Ident::new("__yew_vtag_name", expr.span());
 
+                let void_children = Ident::new("__yew_void_children", Span::mixed_site());
+
                 // handle special attribute value
                 let handle_value_attr = props.value.as_ref().map(|prop| {
                     let v = prop.value.optimize_literals();
@@ -455,7 +452,7 @@ impl ToTokens for HtmlElement {
                                 #key,
                                 #attributes,
                                 #listeners,
-                                #child_list,
+                                #children,
                             );
 
                             #handle_value_attr
@@ -468,7 +465,10 @@ impl ToTokens for HtmlElement {
                     // For literal tags this is already done at compile-time.
                     //
                     // check void element
-                    if !#vtag.children().is_empty() {
+                    if !::std::matches!(
+                        ::yew::virtual_dom::VTag::children(&#vtag),
+                        ::std::option::Option::Some(::yew::virtual_dom::VNode::VList(ref #void_children)) if ::std::vec::Vec::is_empty(#void_children)
+                    ) {
                         ::std::debug_assert!(
                             !::std::matches!(#vtag.tag().to_ascii_lowercase().as_str(),
                                 "area" | "base" | "br" | "col" | "embed" | "hr" | "img" | "input"

packages/yew-macro/src/html_tree/mod.rs

@@ -29,6 +29,8 @@ use html_list::HtmlList;
 use html_node::HtmlNode;
 use tag::TagTokens;
 
+use self::html_block::BlockContent;
+
 pub enum HtmlType {
     Block,
     Component,
@@ -280,6 +282,62 @@ impl HtmlChildrenTree {
 
         Ok(children)
     }
+
+    pub fn to_children_renderer_tokens(&self) -> Option<TokenStream> {
+        if self.0.is_empty() {
+            return None;
+        }
+
+        if let [HtmlTree::Block(ref m)] = self.0[..] {
+            if let HtmlBlock {
+                content: BlockContent::Node(children),
+                ..
+            } = m.as_ref()
+            {
+                return Some(quote! { #children });
+            }
+        }
+
+        if let [HtmlTree::Component(ref children)] = self.0[..] {
+            return Some(quote! { #children });
+        }
+
+        if let [HtmlTree::Element(ref children)] = self.0[..] {
+            return Some(quote! { #children });
+        }
+
+        Some(quote! { ::yew::html::ChildrenRenderer::new(#self) })
+    }
+
+    pub fn to_vnode_tokens(&self) -> TokenStream {
+        if self.0.is_empty() {
+            return quote! {::std::default::Default::default() };
+        }
+
+        if let [HtmlTree::Block(ref m)] = self.0[..] {
+            if let HtmlBlock {
+                content: BlockContent::Node(children),
+                ..
+            } = m.as_ref()
+            {
+                return quote! { ::yew::html::IntoPropValue::<::yew::virtual_dom::VNode>::into_prop_value(#children) };
+            }
+        }
+
+        if let [HtmlTree::Component(ref children)] = self.0[..] {
+            return quote! { ::yew::html::IntoPropValue::<::yew::virtual_dom::VNode>::into_prop_value(#children) };
+        }
+
+        if let [HtmlTree::Element(ref children)] = self.0[..] {
+            return quote! { ::yew::html::IntoPropValue::<::yew::virtual_dom::VNode>::into_prop_value(#children) };
+        }
+
+        quote! {
+            ::yew::html::IntoPropValue::<::yew::virtual_dom::VNode>::into_prop_value(
+                ::yew::html::ChildrenRenderer::new(#self)
+            )
+        }
+    }
 }
 
 impl ToTokens for HtmlChildrenTree {

packages/yew-macro/src/props/component.rs

@@ -131,7 +131,7 @@ impl ComponentProps {
                 });
                 let set_children = children_renderer.map(|children| {
                     quote_spanned! {props_ty.span()=>
-                        #ident.children = #children;
+                        #ident.children = ::yew::html::IntoPropValue::into_prop_value(#children);
                     }
                 });
                 let init_base = quote_spanned! {expr.span().resolved_at(Span::call_site())=>

packages/yew-macro/tests/html_macro/block-fail.stderr

@@ -13,21 +13,6 @@ error[E0277]: `()` doesn't implement `std::fmt::Display`
   = note: required because of the requirements on the impl of `Into<NodeSeq<(), VNode>>` for `()`
   = note: this error originates in the macro `html` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0277]: `()` doesn't implement `std::fmt::Display`
-  --> tests/html_macro/block-fail.rs:12:16
-   |
-12 |         <div>{ not_tree() }</div>
-   |                ^^^^^^^^ `()` cannot be formatted with the default formatter
-   |
-   = help: the trait `std::fmt::Display` is not implemented for `()`
-   = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
-   = note: required because of the requirements on the impl of `ToString` for `()`
-   = note: required because of the requirements on the impl of `From<()>` for `VNode`
-   = note: required because of the requirements on the impl of `Into<VNode>` for `()`
-   = note: 2 redundant requirements hidden
-   = note: required because of the requirements on the impl of `Into<NodeSeq<(), VNode>>` for `()`
-   = note: this error originates in the macro `html` (in Nightly builds, run with -Z macro-backtrace for more info)
-
 error[E0277]: `()` doesn't implement `std::fmt::Display`
   --> tests/html_macro/block-fail.rs:15:17
    |