Implement pure version of component example

Cargo.toml

@@ -90,6 +90,7 @@ members = [
     "examples/tooltip",
     "examples/tour",
     "examples/url_handler",
+    "examples/pure/component",
     "examples/pure/counter",
     "examples/pure/pick_list",
     "examples/pure/todos",

examples/pure/component/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "pure_component"
+version = "0.1.0"
+authors = ["Héctor Ramón Jiménez <hector0193@gmail.com>"]
+edition = "2021"
+publish = false
+
+[dependencies]
+iced = { path = "../../..", features = ["debug", "pure"] }
+iced_native = { path = "../../../native" }
+iced_lazy = { path = "../../../lazy", features = ["pure"] }

examples/pure/component/src/main.rs

@@ -0,0 +1,168 @@
+use iced::pure::widget::container;
+use iced::pure::{Element, Sandbox};
+use iced::{Length, Settings};
+
+use numeric_input::numeric_input;
+
+pub fn main() -> iced::Result {
+    Component::run(Settings::default())
+}
+
+#[derive(Default)]
+struct Component {
+    value: Option<u32>,
+}
+
+#[derive(Debug, Clone, Copy)]
+enum Message {
+    NumericInputChanged(Option<u32>),
+}
+
+impl Sandbox for Component {
+    type Message = Message;
+
+    fn new() -> Self {
+        Self::default()
+    }
+
+    fn title(&self) -> String {
+        String::from("Component - Iced")
+    }
+
+    fn update(&mut self, message: Message) {
+        match message {
+            Message::NumericInputChanged(value) => {
+                self.value = value;
+            }
+        }
+    }
+
+    fn view(&self) -> Element<Message> {
+        container(numeric_input(self.value, Message::NumericInputChanged))
+            .padding(20)
+            .height(Length::Fill)
+            .center_y()
+            .into()
+    }
+}
+
+mod numeric_input {
+    use iced::pure::widget::Element;
+    use iced::pure::widget::{row, text, text_input};
+    use iced_lazy::pure::component::{self, Component};
+    use iced_native::alignment::{self, Alignment};
+    use iced_native::text;
+    use iced_native::Length;
+
+    pub struct NumericInput<Message> {
+        value: Option<u32>,
+        on_change: Box<dyn Fn(Option<u32>) -> Message>,
+    }
+
+    pub fn numeric_input<Message>(
+        value: Option<u32>,
+        on_change: impl Fn(Option<u32>) -> Message + 'static,
+    ) -> NumericInput<Message> {
+        NumericInput::new(value, on_change)
+    }
+
+    #[derive(Debug, Clone)]
+    pub enum Event {
+        InputChanged(String),
+        IncrementPressed,
+        DecrementPressed,
+    }
+
+    impl<Message> NumericInput<Message> {
+        pub fn new(
+            value: Option<u32>,
+            on_change: impl Fn(Option<u32>) -> Message + 'static,
+        ) -> Self {
+            Self {
+                value,
+                on_change: Box::new(on_change),
+            }
+        }
+    }
+
+    impl<Message, Renderer> Component<Message, Renderer> for NumericInput<Message>
+    where
+        Renderer: text::Renderer + 'static,
+    {
+        type State = ();
+        type Event = Event;
+
+        fn update(
+            &mut self,
+            _state: &mut Self::State,
+            event: Event,
+        ) -> Option<Message> {
+            match event {
+                Event::IncrementPressed => Some((self.on_change)(Some(
+                    self.value.unwrap_or_default().saturating_add(1),
+                ))),
+                Event::DecrementPressed => Some((self.on_change)(Some(
+                    self.value.unwrap_or_default().saturating_sub(1),
+                ))),
+                Event::InputChanged(value) => {
+                    if value.is_empty() {
+                        Some((self.on_change)(None))
+                    } else {
+                        value
+                            .parse()
+                            .ok()
+                            .map(Some)
+                            .map(self.on_change.as_ref())
+                    }
+                }
+            }
+        }
+
+        fn view(&self, _state: &Self::State) -> Element<Event, Renderer> {
+            let button = |label, on_press| {
+                use iced::pure::widget::button;
+
+                button(
+                    text(label)
+                        .width(Length::Fill)
+                        .height(Length::Fill)
+                        .horizontal_alignment(alignment::Horizontal::Center)
+                        .vertical_alignment(alignment::Vertical::Center),
+                )
+                .width(Length::Units(50))
+                .on_press(on_press)
+            };
+
+            row()
+                .push(button("-", Event::DecrementPressed))
+                .push(
+                    text_input(
+                        "Type a number",
+                        self.value
+                            .as_ref()
+                            .map(u32::to_string)
+                            .as_ref()
+                            .map(String::as_str)
+                            .unwrap_or(""),
+                        Event::InputChanged,
+                    )
+                    .padding(10),
+                )
+                .push(button("+", Event::IncrementPressed))
+                .align_items(Alignment::Fill)
+                .spacing(10)
+                .into()
+        }
+    }
+
+    impl<'a, Message, Renderer> From<NumericInput<Message>>
+        for Element<'a, Message, Renderer>
+    where
+        Message: 'a,
+        Renderer: 'static + text::Renderer,
+    {
+        fn from(numeric_input: NumericInput<Message>) -> Self {
+            component::view(numeric_input)
+        }
+    }
+}