Implicit optional attributes (#1637)

.github/workflows/pull-request.yml

@@ -198,7 +198,7 @@ jobs:
     strategy:
       matrix:
         toolchain:
-          - 1.45.0 # MSRV
+          - 1.51.0 # min version with const generics
           - stable
           - nightly
 

CONTRIBUTING.md

@@ -68,9 +68,10 @@ Alternatively, you can set the `ECHO_SERVER_URL` environment variable to the URL
 
 When adding or updating tests, please make sure to update the appropriate `stderr` file, which you can find [here](https://github.com/yewstack/yew/tree/master/packages/yew-macro/tests/macro) for the `html!` macro.
 These files ensure that macro compilation errors are correct and easy to understand.
-These errors can change with each release of the compiler so they should be generated with the MSRV (currently 1.45).
+These errors can change with each release of the compiler so they should be generated with the Rust version 1.51 
+(because some tests make use of const generics which were stabilized in that version).
 
-To update or generate a new `stderr` file you can run `TRYBUILD=overwrite cargo +1.45.2 test` in the `yew-macro` directory.
+To update or generate a new `stderr` file you can run `cargo make test-overwrite` in the `yew-macro` directory.
 
 ## Linting
 

docs/concepts/function-components/attribute.md

@@ -30,7 +30,7 @@ pub fn rendered_at(props: &RenderedAtProps) -> Html {
     html! {
         <p>
             <b>{ "Rendered at: " }</b>
-            { &props.time }
+            { props.time.clone() }
         </p>
     }
 }
@@ -46,7 +46,7 @@ fn app() -> Html {
         let counter = Rc::clone(&counter);
         Callback::from(move |_| set_counter(*counter + 1))
     };
-    
+
     html! {
         <div>
             <button onclick=onclick>{ "Increment value" }</button>

docs/concepts/html/components.md

@@ -67,7 +67,7 @@ impl Component for Container {
 
     fn view(&self) -> Html {
        html! {
-           <div id=&self.0.id>
+           <div id=self.0.id.clone()>
                { self.0.children.clone() }
            </div>
        }
@@ -112,45 +112,6 @@ impl Component for List {
 }
 ```
 
-## Transformers
-
-Whenever you set a prop its value goes through a transformation step first.
-If the value already has the correct type, this step doesn't do anything.
-However, transformers can be useful to reduce code repetition.
-
-The following is a list of transformers you should know about:
-
-- `&T` -> `T`
-
-  Clones the reference to get an owned value.
-
-- `&str` -> `String`
-
-  Allows you to use string literals without adding `.to_owned()` at the end.
-
-- `T` -> `Option<T>`
-
-  Wraps the value in `Some`.
-
-```rust
-struct Props {
-    unique_id: Option<usize>,
-    text: String,
-}
-
-struct Model;
-impl Component for Model {
-    type Properties = Props;
-
-    // ...
-}
-
-// transformers allow you to write this:
-html! { <Model unique_id=5 text="literals are fun" /> };
-// instead of:
-html! { <Model unique_id=Some(5) text="literals are fun".to_owned() /> };
-```
-
 ## Relevant examples
 - [Boids](https://github.com/yewstack/yew/tree/master/examples/boids)
 - [Router](https://github.com/yewstack/yew/tree/master/examples/router)

docs/concepts/html/elements.md

@@ -15,26 +15,36 @@ let level = 5;
 let text = "Hello World!".to_owned()
 
 html! {
-    <@{format!("h{}", level)} class="title">{ content }</@>
+    <@{format!("h{}", level)} class="title">{ text }</@>
 }
 ```
 
 ## Optional attributes for HTML elements
 
-Most HTML attributes can be marked as optional by placing a `?` in front of
-the `=` sign. This makes them accept the same type of value as otherwise, but
-wrapped in an `Option<T>`:
+Most HTML attributes can use optional values (`Some(x)` or `None`). This allows us
+to omit the attribute if the attribute is marked as optional.
 
 ```rust
 let maybe_id = Some("foobar");
 
 html! {
-    <div id?=maybe_id></div>
+    <div id=maybe_id></div>
 }
 ```
 
 If the attribute is set to `None`, the attribute won't be set in the DOM.
 
+Please note that it is also valid to give only the value as properties behave
+like `Into<Option<T>>`:
+
+```rust
+let id = "foobar";
+
+html! {
+    <div id=id></div>
+}
+```
+
 ## Listeners
 
 Listener attributes need to be passed a `Callback` which is a wrapper around a closure. How you create your callback depends on how you wish your app to react to a listener event:

examples/boids/src/slider.rs

@@ -80,13 +80,13 @@ impl Component for Slider {
 
         html! {
             <div class="slider">
-                <label for=id class="slider__label">{ label }</label>
+                <label for=id.clone() class="slider__label">{ label }</label>
                 <input type="range"
                     id=id
                     class="slider__input"
-                    min=min max=max step=step
+                    min=min.to_string() max=max.to_string() step=step.to_string()
                     oninput=onchange.reform(|data: InputData| data.value.parse().unwrap())
-                    value=value
+                    value=value.to_string()
                 />
                 <span class="slider__value">{ display_value }</span>
             </div>

examples/crm/src/add_client.rs

@@ -78,19 +78,19 @@ impl Component for AddClientForm {
                     <input
                         class=classes!("new-client", "firstname")
                         placeholder="First name"
-                        value=&client.first_name
+                        value=client.first_name.clone()
                         oninput=link.callback(|e: InputData| Msg::UpdateFirstName(e.value))
                     />
                     <input
                         class=classes!("new-client", "lastname")
                         placeholder="Last name"
-                        value=&client.last_name
+                        value=client.last_name.clone()
                         oninput=link.callback(|e: InputData| Msg::UpdateLastName(e.value))
                     />
                     <textarea
                         class=classes!("new-client", "description")
                         placeholder="Description"
-                        value=&client.description
+                        value=client.description.clone()
                         oninput=link.callback(|e: InputData| Msg::UpdateDescription(e.value))
                     />
                 </div>

examples/js_callback/src/main.rs

@@ -58,7 +58,7 @@ impl Component for Model {
                 <textarea
                     class="code-block"
                     oninput=self.link.callback(|input: InputData| Msg::Payload(input.value))
-                    value=&self.payload
+                    value=self.payload.clone()
                 />
                 <button onclick=self.link.callback(|_| Msg::Payload(bindings::get_payload()))>
                     { "Get the payload!" }

examples/keyed_list/src/main.rs

@@ -169,7 +169,7 @@ impl Model {
                             { self.build_component_ratio }
                         </p>
                         <input name="ratio" type="range" class="form-control-range" min="0.0" max="1.0" step="any"
-                            value=self.build_component_ratio
+                            value=self.build_component_ratio.to_string()
                             oninput=self.link.callback(|e: InputData| Msg::ChangeRatio(e.value))
                         />
                     </div>

examples/keyed_list/src/person.rs

@@ -116,9 +116,9 @@ impl PersonType {
             }
             Self::Component(info) => {
                 if keyed {
-                    html! { <PersonComponent key=info.id.to_string() info=info /> }
+                    html! { <PersonComponent key=info.id.to_string() info=info.clone() /> }
                 } else {
-                    html! { <PersonComponent info=info /> }
+                    html! { <PersonComponent info=info.clone() /> }
                 }
             }
         }

examples/mount_point/src/main.rs

@@ -39,7 +39,7 @@ impl Component for Model {
         html! {
             <div>
                 <input
-                    value=&self.name
+                    value=self.name.clone()
                     oninput=self.link.callback(|e: InputData| Msg::UpdateName(e.value))
                 />
                 <p>{ self.name.chars().rev().collect::<String>() }</p>

examples/nested_list/src/list.rs

@@ -40,9 +40,9 @@ where
     }
 }
 
-impl Into<Html> for ListVariant {
-    fn into(self) -> Html {
-        match self.props {
+impl From<ListVariant> for Html {
+    fn from(variant: ListVariant) -> Html {
+        match variant.props {
             Variants::Header(props) => {
                 VComp::new::<ListHeader>(props, NodeRef::default(), None).into()
             }

examples/nested_list/src/main.rs

@@ -7,7 +7,7 @@ use std::cell::RefCell;
 use std::fmt;
 use std::ops::Deref;
 use std::rc::Rc;
-use yew::html::{Component, ComponentLink};
+use yew::html::{Component, ComponentLink, ImplicitClone};
 
 pub struct WeakComponentLink<COMP: Component>(Rc<RefCell<Option<ComponentLink<COMP>>>>);
 
@@ -16,6 +16,7 @@ impl<COMP: Component> Clone for WeakComponentLink<COMP> {
         Self(Rc::clone(&self.0))
     }
 }
+impl<COMP: Component> ImplicitClone for WeakComponentLink<COMP> {}
 
 impl<COMP: Component> Default for WeakComponentLink<COMP> {
     fn default() -> Self {

examples/router/src/components/author_card.rs

@@ -44,7 +44,7 @@ impl Component for AuthorCard {
                     <div class="media">
                         <div class="media-left">
                             <figure class="image is-128x128">
-                                <img src=author.image_url />
+                                <img src=author.image_url.clone() />
                             </figure>
                         </div>
                         <div class="media-content">

examples/router/src/components/post_card.rs

@@ -42,7 +42,7 @@ impl Component for PostCard {
             <div class="card">
                 <div class="card-image">
                     <figure class="image is-2by1">
-                        <img src={ &post.image_url } loading="lazy" />
+                        <img src=post.image_url.clone() loading="lazy" />
                     </figure>
                 </div>
                 <div class="card-content">

examples/router/src/components/progress_delay.rs

@@ -70,7 +70,7 @@ impl Component for ProgressDelay {
     fn view(&self) -> Html {
         let value = self.value;
         html! {
-            <progress class="progress is-primary" value=value max=1.0>
+            <progress class="progress is-primary" value=value.to_string() max=1.0>
                 { format!("{:.0}%", 100.0 * value) }
             </progress>
         }

examples/router/src/pages/author.rs

@@ -54,7 +54,7 @@ impl Component for Author {
                         </div>
                         <div class="tile is-parent">
                             <figure class="tile is-child image is-square">
-                                <img src=author.image_url />
+                                <img src=author.image_url.clone() />
                             </figure>
                         </div>
                         <div class="tile is-parent">

examples/router/src/pages/author_list.rs

@@ -38,7 +38,7 @@ impl Component for AuthorList {
     }
 
     fn view(&self) -> Html {
-        let authors = self.seeds.iter().map(|seed| {
+        let authors = self.seeds.iter().map(|&seed| {
             html! {
                 <div class="tile is-parent">
                     <div class="tile is-child">

examples/router/src/pages/post.rs

@@ -48,7 +48,7 @@ impl Component for Post {
         html! {
             <>
                 <section class="hero is-medium is-light has-background">
-                    <img class="hero-background is-transparent" src=post.image_url />
+                    <img class="hero-background is-transparent" src=post.image_url.clone() />
                     <div class="hero-body">
                         <div class="container">
                             <h1 class="title">
@@ -79,7 +79,7 @@ impl Post {
             <article class="media block box my-6">
                 <figure class="media-left">
                     <p class="image is-64x64">
-                        <img src=quote.author.image_url loading="lazy" />
+                        <img src=quote.author.image_url.clone() loading="lazy" />
                     </p>
                 </figure>
                 <div class="media-content">
@@ -99,7 +99,7 @@ impl Post {
     fn render_section_hero(&self, section: &content::Section) -> Html {
         html! {
             <section class="hero is-dark has-background mt-6 mb-3">
-                <img class="hero-background is-transparent" src=section.image_url loading="lazy" />
+                <img class="hero-background is-transparent" src=section.image_url.clone() loading="lazy" />
                 <div class="hero-body">
                     <div class="container">
                         <h2 class="subtitle">{ &section.title }</h2>

examples/router/src/switch.rs

@@ -1,7 +1,4 @@
-use yew::{
-    virtual_dom::{Transformer, VComp},
-    web_sys::Url,
-};
+use yew::{html::IntoPropValue, web_sys::Url};
 use yew_router::{components::RouterAnchor, prelude::*, switch::Permissive};
 
 #[derive(Clone, Debug, Switch)]
@@ -79,9 +76,9 @@ impl Switch for PublicUrlSwitch {
 
 // this allows us to pass `AppRoute` to components which take `PublicUrlSwitch`.
 
-impl Transformer<AppRoute, PublicUrlSwitch> for VComp {
-    fn transform(from: AppRoute) -> PublicUrlSwitch {
-        from.into_public()
+impl IntoPropValue<PublicUrlSwitch> for AppRoute {
+    fn into_prop_value(self: AppRoute) -> PublicUrlSwitch {
+        self.into_public()
     }
 }
 

examples/store/src/post.rs

@@ -71,7 +71,7 @@ impl Component for Post {
                 <h2>{ format!("Post #{}", self.id) }</h2>
                 <p>{text}</p>
 
-                <TextInput value=text onsubmit=self.link.callback(Msg::UpdateText) />
+                <TextInput value=text.to_owned() onsubmit=self.link.callback(Msg::UpdateText) />
                 <button onclick=self.link.callback(|_| Msg::Delete)>
                     { "Delete" }
                 </button>

examples/store/src/text_input.rs

@@ -57,7 +57,7 @@ impl Component for TextInput {
         html! {
             <input
                 type="text"
-                value=&self.text
+                value=self.text.clone()
                 oninput=self.link.callback(|e: InputData| Msg::SetText(e.value))
                 onkeydown=self.link.batch_callback(move |e: KeyboardEvent| {
                     e.stop_propagation();

examples/todomvc/src/main.rs

@@ -196,7 +196,7 @@ impl Model {
             <input
                 class="new-todo"
                 placeholder="What needs to be done?"
-                value=&self.state.value
+                value=self.state.value.clone()
                 oninput=self.link.callback(|e: InputData| Msg::Update(e.value))
                 onkeypress=self.link.batch_callback(|e: KeyboardEvent| {
                     if e.key() == "Enter" { Some(Msg::Add) } else { None }
@@ -242,7 +242,7 @@ impl Model {
                     class="edit"
                     type="text"
                     ref=self.focus_ref.clone()
-                    value=&self.state.edit_value
+                    value=self.state.edit_value.clone()
                     onmouseover=self.link.callback(|_| Msg::Focus)
                     oninput=self.link.callback(|e: InputData| Msg::UpdateEdit(e.value))
                     onblur=self.link.callback(move |_| Msg::Edit(idx))

packages/yew-components/src/select.rs

@@ -144,7 +144,7 @@ where
         html! {
             <select
                 ref=self.select_ref.clone()
-                id=self.props.id
+                id=self.props.id.clone()
                 class=self.props.class.clone()
                 disabled=self.props.disabled
                 onchange=self.on_change()

packages/yew-dsl/src/lib.rs

@@ -37,9 +37,9 @@ impl<COMP: Component> BoxedVNodeProducer<COMP> {
     }
 }
 
-impl<COMP: Component> Into<VNode> for BoxedVNodeProducer<COMP> {
-    fn into(self) -> VNode {
-        self.build()
+impl<COMP: Component> From<BoxedVNodeProducer<COMP>> for VNode {
+    fn from(value: BoxedVNodeProducer<COMP>) -> VNode {
+        value.build()
     }
 }