Add methods to set ControlFlow operation

This allows downstream users to avoid importing `ControlFlow` from winit.

src/event_loop.rs

@@ -169,6 +169,41 @@ impl ControlFlow {
     /// [`ExitWithCode`]: ControlFlow::ExitWithCode
     #[allow(non_upper_case_globals)]
     pub const Exit: Self = Self::ExitWithCode(0);
+
+    /// Sets this to [`Poll`].
+    ///
+    /// [`Poll`]: ControlFlow::Poll
+    pub fn set_poll(&mut self) {
+        *self = Self::Poll;
+    }
+
+    /// Sets this to [`Wait`].
+    ///
+    /// [`Wait`]: ControlFlow::Wait
+    pub fn set_wait(&mut self) {
+        *self = Self::Wait;
+    }
+
+    /// Sets this to [`WaitUntil`]`(instant)`.
+    ///
+    /// [`WaitUntil`]: ControlFlow::WaitUntil
+    pub fn set_wait_until(&mut self, instant: Instant) {
+        *self = Self::WaitUntil(instant);
+    }
+
+    /// Sets this to [`ExitWithCode`]`(code)`.
+    ///
+    /// [`ExitWithCode`]: ControlFlow::ExitWithCode
+    pub fn set_exit_with_code(&mut self, code: i32) {
+        *self = Self::ExitWithCode(code);
+    }
+
+    /// Sets this to [`Exit`].
+    ///
+    /// [`Exit`]: ControlFlow::Exit
+    pub fn set_exit(&mut self) {
+        *self = Self::Exit;
+    }
 }
 
 impl Default for ControlFlow {

src/lib.rs

@@ -44,7 +44,7 @@
 //! ```no_run
 //! use winit::{
 //!     event::{Event, WindowEvent},
-//!     event_loop::{ControlFlow, EventLoop},
+//!     event_loop::EventLoop,
 //!     window::WindowBuilder,
 //! };
 //!
@@ -54,12 +54,12 @@
 //! event_loop.run(move |event, _, control_flow| {
 //!     // ControlFlow::Poll continuously runs the event loop, even if the OS hasn't
 //!     // dispatched any events. This is ideal for games and similar applications.
-//!     *control_flow = ControlFlow::Poll;
+//!     control_flow.set_poll();
 //!
 //!     // ControlFlow::Wait pauses the event loop if no events are available to process.
 //!     // This is ideal for non-game applications that only update in response to user
 //!     // input, and uses significantly less power/CPU time than ControlFlow::Poll.
-//!     *control_flow = ControlFlow::Wait;
+//!     control_flow.set_wait();
 //!
 //!     match event {
 //!         Event::WindowEvent {
@@ -67,7 +67,7 @@
 //!             ..
 //!         } => {
 //!             println!("The close button was pressed; stopping");
-//!             *control_flow = ControlFlow::Exit
+//!             control_flow.set_exit();
 //!         },
 //!         Event::MainEventsCleared => {
 //!             // Application update code.

src/window.rs

@@ -18,7 +18,7 @@ pub use crate::icon::{BadIcon, Icon};
 /// ```no_run
 /// use winit::{
 ///     event::{Event, WindowEvent},
-///     event_loop::{ControlFlow, EventLoop},
+///     event_loop::EventLoop,
 ///     window::Window,
 /// };
 ///
@@ -26,13 +26,13 @@ pub use crate::icon::{BadIcon, Icon};
 /// let window = Window::new(&event_loop).unwrap();
 ///
 /// event_loop.run(move |event, _, control_flow| {
-///     *control_flow = ControlFlow::Wait;
+///     control_flow.set_wait();
 ///
 ///     match event {
 ///         Event::WindowEvent {
 ///             event: WindowEvent::CloseRequested,
 ///             ..
-///         } => *control_flow = ControlFlow::Exit,
+///         } => control_flow.set_exit(),
 ///         _ => (),
 ///     }
 /// });