feat: add spawn_local

Author: dignifiedquire

src/task/builder.rs

@@ -60,6 +60,20 @@ impl Builder {
         Ok(JoinHandle::new(smol_task, task))
     }
 
+    /// Spawns a task locally with the configured settings.
+    pub fn local<F, T>(self, future: F) -> io::Result<JoinHandle<T>>
+    where
+        F: Future<Output = T> + 'static,
+        T: 'static,
+    {
+        let wrapped = self.build(future);
+
+        let task = wrapped.tag.task().clone();
+        let smol_task = smol::Task::local(wrapped).into();
+
+        Ok(JoinHandle::new(smol_task, task))
+    }
+
     /// Spawns a task with the configured settings, blocking on its execution.
     pub fn blocking<F, T>(self, future: F) -> T
     where

src/task/mod.rs

@@ -139,6 +139,7 @@ cfg_default! {
     pub use join_handle::JoinHandle;
     pub use sleep::sleep;
     pub use spawn::spawn;
+    pub use spawn_local::spawn_local;
     pub use task_local::{AccessError, LocalKey};
 
     pub(crate) use task_local::LocalsMap;
@@ -151,6 +152,7 @@ cfg_default! {
     mod sleep;
     mod spawn;
     mod spawn_blocking;
+    mod spawn_local;
     mod task;
     mod task_id;
     mod task_local;

src/task/spawn_local.rs

@@ -0,0 +1,32 @@
+use std::future::Future;
+
+use crate::task::{Builder, JoinHandle};
+
+/// Spawns a task onto the thread-local executor.
+///
+/// This function is similar to [`std::thread::spawn`], except it spawns an asynchronous task.
+///
+/// [`std::thread`]: https://doc.rust-lang.org/std/thread/fn.spawn.html
+///
+/// # Examples
+///
+/// ```
+/// # async_std::task::block_on(async {
+/// #
+/// use async_std::task;
+///
+/// let handle = task::spawn_local(async {
+///     1 + 2
+/// });
+///
+/// assert_eq!(handle.await, 3);
+/// #
+/// # })
+/// ```
+pub fn spawn_local<F, T>(future: F) -> JoinHandle<T>
+where
+    F: Future<Output = T> + 'static,
+    T: 'static,
+{
+    Builder::new().local(future).expect("cannot spawn task")
+}