Make Command implementations platform-specific

This allows us to introduce a platform-specific `Action` to both `iced_native`
and `iced_web` and remove the `Clipboard` from `Application::update` to maintain
purity.

Additionally, this should let us implement further actions to let users query
and modify the shell environment (e.g. window, clipboard, and more!)

examples/clock/src/main.rs

@@ -1,7 +1,7 @@
 use iced::{
     canvas::{self, Cache, Canvas, Cursor, Geometry, LineCap, Path, Stroke},
-    executor, time, Application, Clipboard, Color, Command, Container, Element,
-    Length, Point, Rectangle, Settings, Subscription, Vector,
+    executor, time, Application, Color, Command, Container, Element, Length,
+    Point, Rectangle, Settings, Subscription, Vector,
 };
 
 pub fn main() -> iced::Result {
@@ -40,11 +40,7 @@ impl Application for Clock {
         String::from("Clock - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::Tick(local_time) => {
                 let now = local_time;

examples/download_progress/src/main.rs

@@ -1,6 +1,6 @@
 use iced::{
-    button, executor, Align, Application, Button, Clipboard, Column, Command,
-    Container, Element, Length, ProgressBar, Settings, Subscription, Text,
+    button, executor, Align, Application, Button, Column, Command, Container,
+    Element, Length, ProgressBar, Settings, Subscription, Text,
 };
 
 mod download;
@@ -43,11 +43,7 @@ impl Application for Example {
         String::from("Download progress - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::Add => {
                 self.last_id = self.last_id + 1;

examples/events/src/main.rs

@@ -1,7 +1,7 @@
 use iced::{
-    button, executor, Align, Application, Button, Checkbox, Clipboard, Column,
-    Command, Container, Element, HorizontalAlignment, Length, Settings,
-    Subscription, Text,
+    button, executor, Align, Application, Button, Checkbox, Column, Command,
+    Container, Element, HorizontalAlignment, Length, Settings, Subscription,
+    Text,
 };
 use iced_native::{window, Event};
 
@@ -40,11 +40,7 @@ impl Application for Events {
         String::from("Events - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::EventOccurred(event) if self.enabled => {
                 self.last.push(event);

examples/game_of_life/src/main.rs

@@ -12,8 +12,8 @@ use iced::slider::{self, Slider};
 use iced::time;
 use iced::window;
 use iced::{
-    Align, Application, Checkbox, Clipboard, Column, Command, Container,
-    Element, Length, Row, Settings, Subscription, Text,
+    Align, Application, Checkbox, Column, Command, Container, Element, Length,
+    Row, Settings, Subscription, Text,
 };
 use preset::Preset;
 use std::time::{Duration, Instant};
@@ -71,11 +71,7 @@ impl Application for GameOfLife {
         String::from("Game of Life - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::Grid(message, version) => {
                 if version == self.version {

examples/integration_opengl/src/controls.rs

@@ -1,7 +1,7 @@
 use iced_glow::Renderer;
 use iced_glutin::{
-    slider, Align, Clipboard, Color, Column, Command, Element, Length, Program,
-    Row, Slider, Text,
+    slider, Align, Color, Column, Command, Element, Length, Program, Row,
+    Slider, Text,
 };
 
 pub struct Controls {
@@ -30,13 +30,8 @@ impl Controls {
 impl Program for Controls {
     type Renderer = Renderer;
     type Message = Message;
-    type Clipboard = Clipboard;
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::BackgroundColorChanged(color) => {
                 self.background_color = color;

examples/integration_wgpu/src/controls.rs

@@ -1,7 +1,7 @@
 use iced_wgpu::Renderer;
 use iced_winit::{
-    slider, Align, Clipboard, Color, Column, Command, Element, Length, Program,
-    Row, Slider, Text,
+    slider, Align, Color, Column, Command, Element, Length, Program, Row,
+    Slider, Text,
 };
 
 pub struct Controls {
@@ -30,13 +30,8 @@ impl Controls {
 impl Program for Controls {
     type Renderer = Renderer;
     type Message = Message;
-    type Clipboard = Clipboard;
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::BackgroundColorChanged(color) => {
                 self.background_color = color;

examples/menu/src/main.rs

@@ -1,7 +1,6 @@
 use iced::menu::{self, Menu};
 use iced::{
-    executor, Application, Clipboard, Command, Container, Element, Length,
-    Settings, Text,
+    executor, Application, Command, Container, Element, Length, Settings, Text,
 };
 use iced_native::keyboard::{Hotkey, KeyCode, Modifiers};
 
@@ -92,11 +91,7 @@ impl Application for App {
         ])
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::MenuActivated(entry) => self.selected = Some(entry),
         }

examples/pane_grid/src/main.rs

@@ -1,8 +1,7 @@
 use iced::{
     button, executor, keyboard, pane_grid, scrollable, Align, Application,
-    Button, Clipboard, Color, Column, Command, Container, Element,
-    HorizontalAlignment, Length, PaneGrid, Row, Scrollable, Settings,
-    Subscription, Text,
+    Button, Color, Column, Command, Container, Element, HorizontalAlignment,
+    Length, PaneGrid, Row, Scrollable, Settings, Subscription, Text,
 };
 use iced_native::{event, subscription, Event};
 
@@ -51,11 +50,7 @@ impl Application for Example {
         String::from("Pane grid - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::Split(axis, pane) => {
                 let result = self.panes.split(

examples/pokedex/src/main.rs

@@ -1,6 +1,6 @@
 use iced::{
-    button, futures, image, Align, Application, Button, Clipboard, Column,
-    Command, Container, Element, Length, Row, Settings, Text,
+    button, futures, image, Align, Application, Button, Column, Command,
+    Container, Element, Length, Row, Settings, Text,
 };
 
 pub fn main() -> iced::Result {
@@ -48,11 +48,7 @@ impl Application for Pokedex {
         format!("{} - Pokédex", subtitle)
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::PokemonFound(Ok(pokemon)) => {
                 *self = Pokedex::Loaded {

examples/solar_system/src/main.rs

@@ -8,8 +8,8 @@
 //! [1]: https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API/Tutorial/Basic_animations#An_animated_solar_system
 use iced::{
     canvas::{self, Cursor, Path, Stroke},
-    executor, time, window, Application, Canvas, Clipboard, Color, Command,
-    Element, Length, Point, Rectangle, Settings, Size, Subscription, Vector,
+    executor, time, window, Application, Canvas, Color, Command, Element,
+    Length, Point, Rectangle, Settings, Size, Subscription, Vector,
 };
 
 use std::time::Instant;
@@ -48,11 +48,7 @@ impl Application for SolarSystem {
         String::from("Solar system - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::Tick(instant) => {
                 self.state.update(instant);

examples/stopwatch/src/main.rs

@@ -1,6 +1,6 @@
 use iced::{
-    button, executor, time, Align, Application, Button, Clipboard, Column,
-    Command, Container, Element, HorizontalAlignment, Length, Row, Settings,
+    button, executor, time, Align, Application, Button, Column, Command,
+    Container, Element, HorizontalAlignment, Length, Row, Settings,
     Subscription, Text,
 };
 use std::time::{Duration, Instant};
@@ -49,11 +49,7 @@ impl Application for Stopwatch {
         String::from("Stopwatch - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::Toggle => match self.state {
                 State::Idle => {

examples/todos/src/main.rs

@@ -1,7 +1,7 @@
 use iced::{
     button, scrollable, text_input, Align, Application, Button, Checkbox,
-    Clipboard, Column, Command, Container, Element, Font, HorizontalAlignment,
-    Length, Row, Scrollable, Settings, Text, TextInput,
+    Column, Command, Container, Element, Font, HorizontalAlignment, Length,
+    Row, Scrollable, Settings, Text, TextInput,
 };
 use serde::{Deserialize, Serialize};
 
@@ -58,11 +58,7 @@ impl Application for Todos {
         format!("Todos{} - Iced", if dirty { "*" } else { "" })
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match self {
             Todos::Loading => {
                 match message {

examples/url_handler/src/main.rs

@@ -1,6 +1,6 @@
 use iced::{
-    executor, Application, Clipboard, Command, Container, Element, Length,
-    Settings, Subscription, Text,
+    executor, Application, Command, Container, Element, Length, Settings,
+    Subscription, Text,
 };
 use iced_native::{
     event::{MacOS, PlatformSpecific},
@@ -34,11 +34,7 @@ impl Application for App {
         String::from("Url - Iced")
     }
 
-    fn update(
-        &mut self,
-        message: Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<Message> {
+    fn update(&mut self, message: Message) -> Command<Message> {
         match message {
             Message::EventOccurred(event) => {
                 if let Event::PlatformSpecific(PlatformSpecific::MacOS(

futures/src/command.rs

@@ -1,138 +0,0 @@
-use crate::BoxFuture;
-use futures::future::{Future, FutureExt};
-
-/// A collection of async operations.
-///
-/// You should be able to turn a future easily into a [`Command`], either by
-/// using the `From` trait or [`Command::perform`].
-pub struct Command<T> {
-    futures: Vec<BoxFuture<T>>,
-}
-
-impl<T> Command<T> {
-    /// Creates an empty [`Command`].
-    ///
-    /// In other words, a [`Command`] that does nothing.
-    pub fn none() -> Self {
-        Self {
-            futures: Vec::new(),
-        }
-    }
-
-    /// Creates a [`Command`] that performs the action of the given future.
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn perform<A>(
-        future: impl Future<Output = T> + 'static + Send,
-        f: impl Fn(T) -> A + 'static + Send,
-    ) -> Command<A> {
-        Command {
-            futures: vec![Box::pin(future.map(f))],
-        }
-    }
-
-    /// Creates a [`Command`] that performs the action of the given future.
-    #[cfg(target_arch = "wasm32")]
-    pub fn perform<A>(
-        future: impl Future<Output = T> + 'static,
-        f: impl Fn(T) -> A + 'static + Send,
-    ) -> Command<A> {
-        Command {
-            futures: vec![Box::pin(future.map(f))],
-        }
-    }
-
-    /// Applies a transformation to the result of a [`Command`].
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn map<A>(
-        mut self,
-        f: impl Fn(T) -> A + 'static + Send + Sync,
-    ) -> Command<A>
-    where
-        T: 'static,
-    {
-        let f = std::sync::Arc::new(f);
-
-        Command {
-            futures: self
-                .futures
-                .drain(..)
-                .map(|future| {
-                    let f = f.clone();
-
-                    Box::pin(future.map(move |result| f(result)))
-                        as BoxFuture<A>
-                })
-                .collect(),
-        }
-    }
-
-    /// Applies a transformation to the result of a [`Command`].
-    #[cfg(target_arch = "wasm32")]
-    pub fn map<A>(mut self, f: impl Fn(T) -> A + 'static) -> Command<A>
-    where
-        T: 'static,
-    {
-        let f = std::rc::Rc::new(f);
-
-        Command {
-            futures: self
-                .futures
-                .drain(..)
-                .map(|future| {
-                    let f = f.clone();
-
-                    Box::pin(future.map(move |result| f(result)))
-                        as BoxFuture<A>
-                })
-                .collect(),
-        }
-    }
-
-    /// Creates a [`Command`] that performs the actions of all the given
-    /// commands.
-    ///
-    /// Once this command is run, all the commands will be executed at once.
-    pub fn batch(commands: impl IntoIterator<Item = Command<T>>) -> Self {
-        Self {
-            futures: commands
-                .into_iter()
-                .flat_map(|command| command.futures)
-                .collect(),
-        }
-    }
-
-    /// Converts a [`Command`] into its underlying list of futures.
-    pub fn futures(self) -> Vec<BoxFuture<T>> {
-        self.futures
-    }
-}
-
-#[cfg(not(target_arch = "wasm32"))]
-impl<T, A> From<A> for Command<T>
-where
-    A: Future<Output = T> + 'static + Send,
-{
-    fn from(future: A) -> Self {
-        Self {
-            futures: vec![future.boxed()],
-        }
-    }
-}
-
-#[cfg(target_arch = "wasm32")]
-impl<T, A> From<A> for Command<T>
-where
-    A: Future<Output = T> + 'static,
-{
-    fn from(future: A) -> Self {
-        Self {
-            futures: vec![future.boxed_local()],
-        }
-    }
-}
-
-impl<T> std::fmt::Debug for Command<T> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_struct("Command").finish()
-    }
-}

futures/src/lib.rs

@@ -10,7 +10,6 @@
 
 pub use futures;
 
-mod command;
 mod runtime;
 
 pub mod executor;
@@ -35,7 +34,6 @@ pub mod subscription;
 )]
 pub mod time;
 
-pub use command::Command;
 pub use executor::Executor;
 pub use runtime::Runtime;
 pub use subscription::Subscription;

futures/src/runtime.rs

@@ -1,5 +1,6 @@
 //! Run commands and keep track of subscriptions.
-use crate::{subscription, Command, Executor, Subscription};
+use crate::BoxFuture;
+use crate::{subscription, Executor, Subscription};
 
 use futures::{channel::mpsc, Sink};
 use std::marker::PhantomData;
@@ -51,22 +52,18 @@ where
     ///
     /// The resulting `Message` will be forwarded to the `Sender` of the
     /// [`Runtime`].
-    pub fn spawn(&mut self, command: Command<Message>) {
+    pub fn spawn(&mut self, future: BoxFuture<Message>) {
         use futures::{FutureExt, SinkExt};
 
-        let futures = command.futures();
+        let mut sender = self.sender.clone();
 
-        for future in futures {
-            let mut sender = self.sender.clone();
+        let future = future.then(|message| async move {
+            let _ = sender.send(message).await;
 
-            let future = future.then(|message| async move {
-                let _ = sender.send(message).await;
+            ()
+        });
 
-                ()
-            });
-
-            self.executor.spawn(future);
-        }
+        self.executor.spawn(future);
     }
 
     /// Tracks a [`Subscription`] in the [`Runtime`].

glutin/src/application.rs

@@ -48,7 +48,7 @@ where
 
     let subscription = application.subscription();
 
-    runtime.spawn(init_command);
+    application::run_command(init_command, &mut runtime);
     runtime.track(subscription);
 
     let context = {
@@ -211,7 +211,6 @@ async fn run_instance<A, E, C>(
                         &mut application,
                         &mut runtime,
                         &mut debug,
-                        &mut clipboard,
                         &mut messages,
                     );
 

native/src/clipboard.rs

@@ -21,3 +21,20 @@ impl Clipboard for Null {
 
     fn write(&mut self, _contents: String) {}
 }
+
+pub enum Action<T> {
+    Read(Box<dyn Fn(Option<String>) -> T>),
+    Write(Box<dyn Fn(String) -> T>),
+}
+
+impl<T> Action<T> {
+    pub fn map<A>(self, f: impl Fn(T) -> A + 'static + Send + Sync) -> Action<A>
+    where
+        T: 'static,
+    {
+        match self {
+            Self::Read(o) => Action::Read(Box::new(move |s| f(o(s)))),
+            Self::Write(o) => Action::Write(Box::new(move |s| f(o(s)))),
+        }
+    }
+}

native/src/command.rs

@@ -0,0 +1,77 @@
+mod action;
+
+pub use action::Action;
+
+use std::future::Future;
+
+/// A set of asynchronous actions to be performed by some runtime.
+pub enum Command<T> {
+    None,
+    Single(Action<T>),
+    Batch(Vec<Action<T>>),
+}
+
+impl<T> Command<T> {
+    /// Creates an empty [`Command`].
+    ///
+    /// In other words, a [`Command`] that does nothing.
+    pub fn none() -> Self {
+        Self::None
+    }
+
+    /// Creates a [`Command`] that performs the action of the given future.
+    pub fn perform<A>(
+        future: impl Future<Output = T> + 'static + Send,
+        f: impl Fn(T) -> A + 'static + Send,
+    ) -> Command<A> {
+        use iced_futures::futures::FutureExt;
+
+        Command::Single(Action::Future(Box::pin(future.map(f))))
+    }
+
+    /// Applies a transformation to the result of a [`Command`].
+    pub fn map<A>(
+        self,
+        f: impl Fn(T) -> A + 'static + Send + Sync + Clone,
+    ) -> Command<A>
+    where
+        T: 'static,
+    {
+        match self {
+            Self::None => Command::None,
+            Self::Single(action) => Command::Single(action.map(f)),
+            Self::Batch(batch) => Command::Batch(
+                batch
+                    .into_iter()
+                    .map(|action| action.map(f.clone()))
+                    .collect(),
+            ),
+        }
+    }
+
+    /// Creates a [`Command`] that performs the actions of all the given
+    /// commands.
+    ///
+    /// Once this command is run, all the commands will be executed at once.
+    pub fn batch(commands: impl IntoIterator<Item = Command<T>>) -> Self {
+        let mut batch = Vec::new();
+
+        for command in commands {
+            match command {
+                Self::None => {}
+                Self::Single(command) => batch.push(command),
+                Self::Batch(commands) => batch.extend(commands),
+            }
+        }
+
+        Self::Batch(batch)
+    }
+
+    pub fn actions(self) -> Vec<Action<T>> {
+        match self {
+            Self::None => Vec::new(),
+            Self::Single(action) => vec![action],
+            Self::Batch(batch) => batch,
+        }
+    }
+}

native/src/command/action.rs

@@ -0,0 +1,24 @@
+use crate::clipboard;
+use crate::window;
+
+pub enum Action<T> {
+    Future(iced_futures::BoxFuture<T>),
+    Clipboard(clipboard::Action<T>),
+    Window(window::Action),
+}
+
+impl<T> Action<T> {
+    /// Applies a transformation to the result of a [`Command`].
+    pub fn map<A>(self, f: impl Fn(T) -> A + 'static + Send + Sync) -> Action<A>
+    where
+        T: 'static,
+    {
+        use iced_futures::futures::FutureExt;
+
+        match self {
+            Self::Future(future) => Action::Future(Box::pin(future.map(f))),
+            Self::Clipboard(action) => Action::Clipboard(action.map(f)),
+            Self::Window(window) => Action::Window(window),
+        }
+    }
+}

native/src/lib.rs

@@ -28,12 +28,13 @@
 //! [`druid`]: https://github.com/xi-editor/druid
 //! [`raw-window-handle`]: https://github.com/rust-windowing/raw-window-handle
 //! [renderer]: crate::renderer
-#![deny(missing_docs)]
-#![deny(missing_debug_implementations)]
+//#![deny(missing_docs)]
+//#![deny(missing_debug_implementations)]
 #![deny(unused_results)]
 #![forbid(unsafe_code)]
 #![forbid(rust_2018_idioms)]
 pub mod clipboard;
+pub mod command;
 pub mod event;
 pub mod keyboard;
 pub mod layout;
@@ -64,12 +65,13 @@ pub use iced_core::{
     menu, Align, Background, Color, Font, HorizontalAlignment, Length, Menu,
     Padding, Point, Rectangle, Size, Vector, VerticalAlignment,
 };
-pub use iced_futures::{executor, futures, Command};
+pub use iced_futures::{executor, futures};
 
 #[doc(no_inline)]
 pub use executor::Executor;
 
 pub use clipboard::Clipboard;
+pub use command::Command;
 pub use debug::Debug;
 pub use element::Element;
 pub use event::Event;

native/src/program.rs

@@ -1,5 +1,5 @@
 //! Build interactive programs using The Elm Architecture.
-use crate::{Clipboard, Command, Element, Renderer};
+use crate::{Command, Element, Renderer};
 
 mod state;
 
@@ -13,9 +13,6 @@ pub trait Program: Sized {
     /// The type of __messages__ your [`Program`] will produce.
     type Message: std::fmt::Debug + Clone + Send;
 
-    /// The type of [`Clipboard`] your [`Program`] will use.
-    type Clipboard: Clipboard;
-
     /// Handles a __message__ and updates the state of the [`Program`].
     ///
     /// This is where you define your __update logic__. All the __messages__,
@@ -24,11 +21,7 @@ pub trait Program: Sized {
     ///
     /// Any [`Command`] returned will be executed immediately in the
     /// background by shells.
-    fn update(
-        &mut self,
-        message: Self::Message,
-        clipboard: &mut Self::Clipboard,
-    ) -> Command<Self::Message>;
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message>;
 
     /// Returns the widgets to display in the [`Program`].
     ///

native/src/program/state.rs

@@ -1,5 +1,6 @@
 use crate::{
-    Cache, Command, Debug, Event, Point, Program, Renderer, Size, UserInterface,
+    Cache, Clipboard, Command, Debug, Event, Point, Program, Renderer, Size,
+    UserInterface,
 };
 
 /// The execution state of a [`Program`]. It leverages caching, event
@@ -91,7 +92,7 @@ where
         bounds: Size,
         cursor_position: Point,
         renderer: &mut P::Renderer,
-        clipboard: &mut P::Clipboard,
+        clipboard: &mut dyn Clipboard,
         debug: &mut Debug,
     ) -> Option<Command<P::Message>> {
         let mut user_interface = build_user_interface(
@@ -135,7 +136,7 @@ where
                     debug.log_message(&message);
 
                     debug.update_started();
-                    let command = self.program.update(message, clipboard);
+                    let command = self.program.update(message);
                     debug.update_finished();
 
                     command

native/src/window.rs

@@ -1,4 +1,6 @@
 //! Build window-based GUI applications.
+mod action;
 mod event;
 
+pub use action::Action;
 pub use event::Event;

native/src/window/action.rs

@@ -0,0 +1,18 @@
+/// An operation to be performed on some window.
+#[derive(Debug)]
+pub enum Action {
+    /// Resize the window.
+    Resize {
+        /// The new logical width of the window
+        width: u32,
+        /// The new logical height of the window
+        height: u32,
+    },
+    /// Move the window.
+    Move {
+        /// The new logical x location of the window
+        x: i32,
+        /// The new logical y location of the window
+        y: i32,
+    },
+}

native/src/window/event.rs

@@ -13,10 +13,9 @@ pub enum Event {
 
     /// A window was resized.
     Resized {
-        /// The new width of the window (in units)
+        /// The new logical width of the window
         width: u32,
-
-        /// The new height of the window (in units)
+        /// The new logical height of the window
         height: u32,
     },
 

src/application.rs

@@ -1,7 +1,5 @@
 use crate::window;
-use crate::{
-    Clipboard, Color, Command, Element, Executor, Menu, Settings, Subscription,
-};
+use crate::{Color, Command, Element, Executor, Menu, Settings, Subscription};
 
 /// An interactive cross-platform application.
 ///
@@ -80,7 +78,7 @@ use crate::{
 ///         String::from("A cool application")
 ///     }
 ///
-///     fn update(&mut self, _message: Self::Message, _clipboard: &mut Clipboard) -> Command<Self::Message> {
+///     fn update(&mut self, _message: Self::Message) -> Command<Self::Message> {
 ///         Command::none()
 ///     }
 ///
@@ -129,11 +127,7 @@ pub trait Application: Sized {
     /// this method.
     ///
     /// Any [`Command`] returned will be executed immediately in the background.
-    fn update(
-        &mut self,
-        message: Self::Message,
-        clipboard: &mut Clipboard,
-    ) -> Command<Self::Message>;
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message>;
 
     /// Returns the event [`Subscription`] for the current state of the
     /// application.
@@ -249,14 +243,9 @@ where
 {
     type Renderer = crate::renderer::Renderer;
     type Message = A::Message;
-    type Clipboard = iced_winit::Clipboard;
 
-    fn update(
-        &mut self,
-        message: Self::Message,
-        clipboard: &mut iced_winit::Clipboard,
-    ) -> Command<Self::Message> {
-        self.0.update(message, clipboard)
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
+        self.0.update(message)
     }
 
     fn view(&mut self) -> Element<'_, Self::Message> {
@@ -329,12 +318,8 @@ where
         self.0.title()
     }
 
-    fn update(
-        &mut self,
-        message: Self::Message,
-        clipboard: &mut Clipboard,
-    ) -> Command<Self::Message> {
-        self.0.update(message, clipboard)
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
+        self.0.update(message)
     }
 
     fn subscription(&self) -> Subscription<Self::Message> {

src/sandbox.rs

@@ -1,6 +1,5 @@
 use crate::{
-    Application, Clipboard, Color, Command, Element, Error, Settings,
-    Subscription,
+    Application, Color, Command, Element, Error, Settings, Subscription,
 };
 
 /// A sandboxed [`Application`].
@@ -162,11 +161,7 @@ where
         T::title(self)
     }
 
-    fn update(
-        &mut self,
-        message: T::Message,
-        _clipboard: &mut Clipboard,
-    ) -> Command<T::Message> {
+    fn update(&mut self, message: T::Message) -> Command<T::Message> {
         T::update(self, message);
 
         Command::none()

web/src/clipboard.rs

@@ -1,21 +0,0 @@
-/// A buffer for short-term storage and transfer within and between
-/// applications.
-#[derive(Debug, Clone, Copy)]
-pub struct Clipboard;
-
-impl Clipboard {
-    /// Creates a new [`Clipboard`].
-    pub fn new() -> Self {
-        Self
-    }
-
-    /// Reads the current content of the [`Clipboard`] as text.
-    pub fn read(&self) -> Option<String> {
-        unimplemented! {}
-    }
-
-    /// Writes the given text contents to the [`Clipboard`].
-    pub fn write(&mut self, _contents: String) {
-        unimplemented! {}
-    }
-}

web/src/command.rs

@@ -0,0 +1,77 @@
+mod action;
+
+pub use action::Action;
+
+#[cfg(target_arch = "wasm32")]
+use std::future::Future;
+
+/// A set of asynchronous actions to be performed by some runtime.
+pub enum Command<T> {
+    None,
+    Single(Action<T>),
+    Batch(Vec<Action<T>>),
+}
+
+impl<T> Command<T> {
+    /// Creates an empty [`Command`].
+    ///
+    /// In other words, a [`Command`] that does nothing.
+    pub fn none() -> Self {
+        Self::None
+    }
+
+    /// Creates a [`Command`] that performs the action of the given future.
+    #[cfg(target_arch = "wasm32")]
+    pub fn perform<A>(
+        future: impl Future<Output = T> + 'static,
+        f: impl Fn(T) -> A + 'static + Send,
+    ) -> Command<A> {
+        use iced_futures::futures::FutureExt;
+
+        Command::Single(Action::Future(Box::pin(future.map(f))))
+    }
+
+    /// Applies a transformation to the result of a [`Command`].
+    #[cfg(target_arch = "wasm32")]
+    pub fn map<A>(mut self, f: impl Fn(T) -> A + 'static + Clone) -> Command<A>
+    where
+        T: 'static,
+    {
+        match self {
+            Self::None => Command::None,
+            Self::Single(action) => Command::Single(action.map(f)),
+            Self::Batch(batch) => Command::Batch(
+                batch
+                    .into_iter()
+                    .map(|action| action.map(f.clone()))
+                    .collect(),
+            ),
+        }
+    }
+
+    /// Creates a [`Command`] that performs the actions of all the given
+    /// commands.
+    ///
+    /// Once this command is run, all the commands will be executed at once.
+    pub fn batch(commands: impl IntoIterator<Item = Command<T>>) -> Self {
+        let mut batch = Vec::new();
+
+        for command in commands {
+            match command {
+                Self::None => {}
+                Self::Single(command) => batch.push(command),
+                Self::Batch(commands) => batch.extend(commands),
+            }
+        }
+
+        Self::Batch(batch)
+    }
+
+    pub fn actions(self) -> Vec<Action<T>> {
+        match self {
+            Self::None => Vec::new(),
+            Self::Single(action) => vec![action],
+            Self::Batch(batch) => batch,
+        }
+    }
+}

web/src/command/action.rs

@@ -0,0 +1,18 @@
+pub enum Action<T> {
+    Future(iced_futures::BoxFuture<T>),
+}
+
+impl<T> Action<T> {
+    /// Applies a transformation to the result of a [`Command`].
+    #[cfg(target_arch = "wasm32")]
+    pub fn map<A>(self, f: impl Fn(T) -> A + 'static) -> Action<A>
+    where
+        T: 'static,
+    {
+        use iced_futures::futures::FutureExt;
+
+        match self {
+            Self::Future(future) => Action::Future(Box::pin(future.map(f))),
+        }
+    }
+}

web/src/lib.rs

@@ -50,8 +50,8 @@
 //! [`wasm-pack`]: https://github.com/rustwasm/wasm-pack
 //! [`wasm-bindgen`]: https://github.com/rustwasm/wasm-bindgen
 //! [`tour` example]: https://github.com/hecrj/iced/tree/0.3/examples/tour
-#![deny(missing_docs)]
-#![deny(missing_debug_implementations)]
+//#![deny(missing_docs)]
+//#![deny(missing_debug_implementations)]
 #![deny(unused_results)]
 #![forbid(unsafe_code)]
 #![forbid(rust_2018_idioms)]
@@ -59,7 +59,7 @@ use dodrio::bumpalo;
 use std::{cell::RefCell, rc::Rc};
 
 mod bus;
-mod clipboard;
+mod command;
 mod element;
 mod hasher;
 
@@ -68,7 +68,7 @@ pub mod subscription;
 pub mod widget;
 
 pub use bus::Bus;
-pub use clipboard::Clipboard;
+pub use command::Command;
 pub use css::Css;
 pub use dodrio;
 pub use element::Element;
@@ -77,7 +77,7 @@ pub use iced_core::{
     keyboard, menu, mouse, Align, Background, Color, Font, HorizontalAlignment,
     Length, Menu, Padding, Point, Rectangle, Size, Vector, VerticalAlignment,
 };
-pub use iced_futures::{executor, futures, Command};
+pub use iced_futures::{executor, futures};
 pub use subscription::Subscription;
 
 #[doc(no_inline)]
@@ -128,11 +128,7 @@ pub trait Application {
     /// this method.
     ///
     /// Any [`Command`] returned will be executed immediately in the background.
-    fn update(
-        &mut self,
-        message: Self::Message,
-        clipboard: &mut Clipboard,
-    ) -> Command<Self::Message>;
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message>;
 
     /// Returns the widgets to display in the [`Application`].
     ///
@@ -162,8 +158,6 @@ pub trait Application {
         let document = window.document().unwrap();
         let body = document.body().unwrap();
 
-        let mut clipboard = Clipboard::new();
-
         let (sender, receiver) =
             iced_futures::futures::channel::mpsc::unbounded();
 
@@ -177,7 +171,7 @@ pub trait Application {
         let mut title = app.title();
         document.set_title(&title);
 
-        runtime.spawn(command);
+        run_command(command, &mut runtime);
 
         let application = Rc::new(RefCell::new(app));
 
@@ -190,8 +184,7 @@ pub trait Application {
 
         let event_loop = receiver.for_each(move |message| {
             let (command, subscription) = runtime.enter(|| {
-                let command =
-                    application.borrow_mut().update(message, &mut clipboard);
+                let command = application.borrow_mut().update(message);
                 let subscription = application.borrow().subscription();
 
                 (command, subscription)
@@ -199,7 +192,7 @@ pub trait Application {
 
             let new_title = application.borrow().title();
 
-            runtime.spawn(command);
+            run_command(command, &mut runtime);
             runtime.track(subscription);
 
             if title != new_title {
@@ -350,8 +343,7 @@ pub trait Embedded {
         );
 
         let (app, command) = runtime.enter(|| Self::new(flags));
-
-        runtime.spawn(command);
+        run_command(command, &mut runtime);
 
         let application = Rc::new(RefCell::new(app));
 
@@ -370,7 +362,7 @@ pub trait Embedded {
                 (command, subscription)
             });
 
-            runtime.spawn(command);
+            run_command(command, &mut runtime);
             runtime.track(subscription);
 
             vdom.weak().schedule_render();
@@ -382,6 +374,25 @@ pub trait Embedded {
     }
 }
 
+fn run_command<Message: 'static + Send, E: Executor>(
+    command: Command<Message>,
+    runtime: &mut iced_futures::Runtime<
+        Hasher,
+        (),
+        E,
+        iced_futures::futures::channel::mpsc::UnboundedSender<Message>,
+        Message,
+    >,
+) {
+    for action in command.actions() {
+        match action {
+            command::Action::Future(future) => {
+                runtime.spawn(future);
+            }
+        }
+    }
+}
+
 struct EmbeddedInstance<A: Embedded> {
     application: Rc<RefCell<A>>,
     bus: Bus<A::Message>,

winit/src/application.rs

@@ -30,7 +30,7 @@ use std::mem::ManuallyDrop;
 ///
 /// When using an [`Application`] with the `debug` feature enabled, a debug view
 /// can be toggled by pressing `F12`.
-pub trait Application: Program<Clipboard = Clipboard> {
+pub trait Application: Program {
     /// The data needed to initialize your [`Application`].
     type Flags;
 
@@ -143,7 +143,7 @@ where
 
     let subscription = application.subscription();
 
-    runtime.spawn(init_command);
+    run_command(init_command, &mut runtime);
     runtime.track(subscription);
 
     let window = settings
@@ -290,7 +290,6 @@ async fn run_instance<A, E, C>(
                         &mut application,
                         &mut runtime,
                         &mut debug,
-                        &mut clipboard,
                         &mut messages,
                     );
 
@@ -492,19 +491,36 @@ pub fn update<A: Application, E: Executor>(
     application: &mut A,
     runtime: &mut Runtime<E, Proxy<A::Message>, A::Message>,
     debug: &mut Debug,
-    clipboard: &mut A::Clipboard,
     messages: &mut Vec<A::Message>,
 ) {
     for message in messages.drain(..) {
         debug.log_message(&message);
 
         debug.update_started();
-        let command = runtime.enter(|| application.update(message, clipboard));
+        let command = runtime.enter(|| application.update(message));
         debug.update_finished();
 
-        runtime.spawn(command);
+        run_command(command, runtime);
     }
 
     let subscription = application.subscription();
     runtime.track(subscription);
 }
+
+/// Runs the actions of a [`Command`].
+pub fn run_command<Message: 'static + Send, E: Executor>(
+    command: Command<Message>,
+    runtime: &mut Runtime<E, Proxy<Message>, Message>,
+) {
+    use iced_native::command;
+
+    for action in command.actions() {
+        match action {
+            command::Action::Future(future) => {
+                runtime.spawn(future);
+            }
+            command::Action::Clipboard(_action) => unimplemented! {},
+            command::Action::Window(_action) => unimplemented! {},
+        }
+    }
+}

winit/src/window.rs

@@ -0,0 +1,7 @@
+pub use iced_native::window::*;
+
+/// The window of an [`Application`].
+///
+/// [`Application`]: crate::Application
+#[derive(Debug)]
+pub struct Window {}