seed-rs · glennsl · May 1, 2021 · May 2, 2021 · May 2, 2021 · May 3, 2021
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -14,6 +14,7 @@
 - Added macro `raw_svg!` (#589).
 - Added `browser::dom::Namespace` to `prelude`. 
 - Adapted to Rust 1.51.0.
+- Added an experimental component API, feature-flagged behind `experimental-component-api`, and the `experimental-component` example to demonstrate its use.
 
 ## v0.8.0
 - [BREAKING] Rename `linear_gradient!` to `linearGradient!` for consistency with the other svg macros (same with `radial_gradient!` and `mesh_gradient!`) (#377).

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -129,6 +129,7 @@ members = [
     "examples/custom_elements",
     "examples/drop_zone",
     "examples/el_key",
+    "examples/experimental_component",
     "examples/graphql",
     "examples/i18n",
     "examples/markdown",
@@ -163,3 +164,4 @@ exclude = [
 default = ["panic-hook"]
 panic-hook = ["console_error_panic_hook"]
 markdown = ["pulldown-cmark"]
+experimental-component-api = []
diff --git a/examples/experimental_component/Cargo.toml b/examples/experimental_component/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "experimental_component"
+version = "0.1.0"
+authors = ["glennsl"]
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+seed = { path = "../../", features = ["experimental-component-api"] }
diff --git a/examples/experimental_component/Makefile.toml b/examples/experimental_component/Makefile.toml
@@ -0,0 +1,27 @@
+extend = "../../Makefile.toml"
+
+# ---- BUILD ----
+
+[tasks.build]
+alias = "default_build"
+
+[tasks.build_release]
+alias = "default_build_release"
+
+# ---- START ----
+
+[tasks.start]
+alias = "default_start"
+
+[tasks.start_release]
+alias = "default_start_release"
+
+# ---- TEST ----
+
+[tasks.test_firefox]
+alias = "default_test_firefox"
+
+# ---- LINT ----
+
+[tasks.clippy]
+alias = "default_clippy"
diff --git a/examples/experimental_component/README.md b/examples/experimental_component/README.md
@@ -0,0 +1,11 @@
+## Experimental component API example
+
+Demonstrates how to use the experimental component API.
+
+---
+
+```bash
+cargo make start
+```
+
+Open [127.0.0.1:8000](http://127.0.0.1:8000) in your browser.
diff --git a/examples/experimental_component/index.html b/examples/experimental_component/index.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+  <meta charset="utf-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
+  <title>Experimental component API example</title>
+</head>
+
+<body>
+  <section id="app"></section>
+  <script type="module">
+    import init from '/pkg/package.js';
+    init('/pkg/package_bg.wasm');
+  </script>
+</body>
+
+</html>
diff --git a/examples/experimental_component/src/button.rs b/examples/experimental_component/src/button.rs
@@ -0,0 +1,97 @@
+#![allow(dead_code)]
+
+use seed::{prelude::*, *};
+use std::borrow::Cow;
+use std::rc::Rc;
+
+pub struct Button<S> {
+    pub label: S,
+}
+
+impl<S: Into<Cow<'static, str>>> Button<S> {
+    pub fn into_component<Ms>(self) -> ButtonComponent<Ms> {
+        ButtonComponent {
+            label: self.label.into(),
+            outlined: false,
+            disabled: false,
+            on_clicks: Vec::new(),
+        }
+    }
+}
+
+#[allow(clippy::module_name_repetitions)]
+pub struct ButtonComponent<Ms: 'static> {
+    label: Cow<'static, str>,
+    outlined: bool,
+    disabled: bool,
+    on_clicks: Vec<Rc<dyn Fn() -> Ms>>,
+}
+
+impl<Ms> ButtonComponent<Ms> {
+    pub const fn outlined(mut self, outlined: bool) -> Self {
+        self.outlined = outlined;
+        self
+    }
+
+    pub const fn disabled(mut self, disabled: bool) -> Self {
+        self.disabled = disabled;
+        self
+    }
+
+    pub fn on_click(mut self, on_click: impl FnOnce() -> Ms + Clone + 'static) -> Self {
+        self.on_clicks.push(Rc::new(move || on_click.clone()()));
+        self
+    }
+}
+
+impl<Ms> Component<Ms> for ButtonComponent<Ms> {
+    fn render(&self) -> Node<Ms> {
+        let attrs = {
+            let mut attrs = attrs! {};
+
+            if self.disabled {
+                attrs.add(At::from("aria-disabled"), true);
+                attrs.add(At::TabIndex, -1);
+                attrs.add(At::Disabled, AtValue::None);
+            }
+
+            attrs
+        };
+
+        let css = {
+            let color = "teal";
+
+            let mut css = style! {
+                St::TextDecoration => "none",
+            };
+
+            if self.outlined {
+                css.merge(style! {
+                    St::Color => color,
+                    St::BackgroundColor => "transparent",
+                    St::Border => format!("{} {} {}", px(2), "solid", color),
+                });
+            } else {
+                css.merge(style! { St::Color => "white", St::BackgroundColor => color });
+            };
+
+            if self.disabled {
+                css.merge(style! {St::Opacity => 0.5});
+            } else {
+                css.merge(style! {St::Cursor => "pointer"});
+            }
+
+            css
+        };
+
+        let mut button = button![css, attrs, self.label];
+
+        if !self.disabled {
+            for on_click in self.on_clicks.iter().cloned() {
+                button.add_event_handler(ev(Ev::Click, move |_| on_click()));
+            }
+        }
+
+        button
+    }
+}
diff --git a/examples/experimental_component/src/lib.rs b/examples/experimental_component/src/lib.rs
@@ -0,0 +1,77 @@
+use seed::{prelude::*, *};
+
+mod button;
+use button::Button;
+
+// ------ ------
+//     Init
+// ------ ------
+
+fn init(_: Url, _: &mut impl Orders<Msg>) -> Model {
+    Model::default()
+}
+
+// ------ ------
+//     Model
+// ------ ------
+
+type Model = i32;
+
+// ------ ------
+//    Update
+// ------ ------
+
+enum Msg {
+    Increment(i32),
+    Decrement(i32),
+}
+
+#[allow(clippy::needless_pass_by_value)]
+fn update(msg: Msg, model: &mut Model, _: &mut impl Orders<Msg>) {
+    match msg {
+        Msg::Increment(d) => *model += d,
+        Msg::Decrement(d) => *model -= d,
+    }
+}
+
+// ------ ------
+//     View
+// ------ ------
+
+#[allow(clippy::trivially_copy_pass_by_ref)]
+fn view(model: &Model) -> Node<Msg> {
+    div![
+        style! {
+            St::Display => "flex"
+            St::AlignItems => "center",
+        },
+        comp![Button { label: "-100" },
+            disabled => true,
+            on_click => || Msg::Decrement(100),
+        ],
+        comp![Button { label: "-10" }, on_click => || Msg::Decrement(10)],
+        comp![Button { label: "-1" },
+            outlined => true,
+            on_click => || Msg::Decrement(1),
+        ],
+        div![style! { St::Margin => "0 1em" }, model],
+        comp![Button { label: "+1" },
+            outlined => true,
+            on_click => || Msg::Increment(1),
+        ],
+        comp![Button { label: "+10" }, on_click => || Msg::Increment(10)],
+        comp![Button { label: "+100" },
+              disabled => true,
+              on_click => || Msg::Increment(100),
+        ]
+    ]
+}
+
+// ------ ------
+//     Start
+// ------ ------
+
+#[wasm_bindgen(start)]
+pub fn start() {
+    App::start("app", init, update, view);
+}
diff --git a/src/lib.rs b/src/lib.rs
@@ -198,8 +198,8 @@ pub mod prelude {
         // https://github.com/rust-lang-nursery/reference/blob/master/src/macros-by-example.md
         shortcuts::*,
         virtual_dom::{
-            el_key, el_ref::el_ref, AsAtValue, At, AtValue, CSSValue, El, ElRef, Ev, EventHandler,
-            IntoNodes, Node, St, Tag, ToClasses, UpdateEl, UpdateElForIterator, View,
+            el_key, el_ref::el_ref, AsAtValue, At, AtValue, CSSValue, Component, El, ElRef, Ev,
+            EventHandler, IntoNodes, Node, St, Tag, ToClasses, UpdateEl, UpdateElForIterator, View,
         },
     };
     pub use indexmap::IndexMap; // for attrs and style to work.

diff --git a/src/shortcuts.rs b/src/shortcuts.rs
@@ -553,3 +553,17 @@ macro_rules! key_value_pairs {
         }
      };
 }
+
+#[cfg(feature = "experimental-component-api")]
+/// Instantiates and renders a `Component`
+///
+/// NOTE: This is an experimental API that requires the `experimental-component-api` feature.
+#[macro_export]
+macro_rules! comp {
+    ($init:expr, $($opt_field:ident => $opt_val:expr),* $(,)?) => {
+        $crate::virtual_dom::component::instantiate(
+            $init.into_component()
+                $( .$opt_field($opt_val) )*
+        )
+    };
+}
diff --git a/src/virtual_dom.rs b/src/virtual_dom.rs
@@ -1,4 +1,5 @@
 pub mod attrs;
+pub mod component;
 pub mod el_ref;
 pub mod event_handler_manager;
 pub mod mailbox;
@@ -11,6 +12,7 @@ pub mod values;
 pub mod view;
 
 pub use attrs::Attrs;
+pub use component::Component;
 pub use el_ref::{el_ref, ElRef, SharedNodeWs};
 pub use event_handler_manager::{EventHandler, EventHandlerManager, Listener};
 pub use mailbox::Mailbox;

diff --git a/src/virtual_dom/component.rs b/src/virtual_dom/component.rs
@@ -0,0 +1,17 @@
+use super::Node;
+
+pub trait Component<Ms> {
+    fn render(&self) -> Node<Ms>;
+}
+
+#[allow(clippy::needless_pass_by_value)]
+pub fn instantiate<Ms, C: Component<Ms>>(component: C) -> Node<Ms> {
+    // TODO: This is where we'd create a boundary node and a state container
+    // that can then either be passed to `render` to be populated, or capture
+    // hook calls indirectly like React does.
+    //
+    // The boundary node will own the state container and remember the component
+    // configuration, so that it can do a local re-render when triggered by a
+    // hook.
+    component.render()
+}