From c7e63852341840f67f8b6164f4aea458960ebd56 Mon Sep 17 00:00:00 2001
From: Per Lindgren <per.lindgren@ltu.se>
Date: Sat, 24 Oct 2020 19:47:38 +0200
Subject: [PATCH] extern examples added

---
 CHANGELOG.md             |  2 ++
 examples/extern_binds.rs | 48 ++++++++++++++++++++++++++++++++++++++++
 examples/extern_spawn.rs | 34 ++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 examples/extern_binds.rs
 create mode 100644 examples/extern_spawn.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec19bd160d..75ffdca58c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   - `#[task_local]`, there must be only one task, similar to a task local
     resource, but (optionally) set-up by init. This is similar to move.
 
+- Improved ergonomics allowing separation of task signatures to actual implementation in extern block `externt "C" { #[task(..)] fn t(..); }`.
+
 ### Changed
 
 - [breaking-change] [PR 400] Move dispatchers from extern block to app argument.
diff --git a/examples/extern_binds.rs b/examples/extern_binds.rs
new file mode 100644
index 0000000000..5a43b341ee
--- /dev/null
+++ b/examples/extern_binds.rs
@@ -0,0 +1,48 @@
+//! examples/extern_binds.rs
+
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use cortex_m_semihosting::hprintln;
+use panic_semihosting as _;
+
+fn foo(_: app::foo::Context) {
+    hprintln!("foo called").ok();
+}
+
+// `examples/interrupt.rs` rewritten to use `binds`
+#[rtic::app(device = lm3s6965)]
+mod app {
+    use crate::foo;
+    use cortex_m_semihosting::{debug, hprintln};
+    use lm3s6965::Interrupt;
+
+    #[init]
+    fn init(_: init::Context) -> init::LateResources {
+        rtic::pend(Interrupt::UART0);
+
+        hprintln!("init").unwrap();
+
+        init::LateResources {}
+    }
+
+    #[idle]
+    fn idle(_: idle::Context) -> ! {
+        hprintln!("idle").unwrap();
+
+        rtic::pend(Interrupt::UART0);
+
+        debug::exit(debug::EXIT_SUCCESS);
+
+        loop {
+            cortex_m::asm::nop();
+        }
+    }
+
+    extern "C" {
+        #[task(binds = UART0)]
+        fn foo(_: foo::Context);
+    }
+}
diff --git a/examples/extern_spawn.rs b/examples/extern_spawn.rs
new file mode 100644
index 0000000000..7dbac2e8df
--- /dev/null
+++ b/examples/extern_spawn.rs
@@ -0,0 +1,34 @@
+//! examples/spawn.rs
+
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use cortex_m_semihosting::{debug, hprintln};
+use panic_semihosting as _;
+
+fn foo(_c: app::foo::Context, x: i32, y: u32) {
+    hprintln!("foo {}, {}", x, y).unwrap();
+    if x == 2 {
+        debug::exit(debug::EXIT_SUCCESS);
+    }
+    app::foo::spawn(2, 3).unwrap();
+}
+
+#[rtic::app(device = lm3s6965, dispatchers = [SSI0])]
+mod app {
+    use crate::foo;
+
+    #[init]
+    fn init(_c: init::Context) -> init::LateResources {
+        foo::spawn(1, 2).unwrap();
+
+        init::LateResources {}
+    }
+
+    extern "C" {
+        #[task()]
+        fn foo(_c: foo::Context, _x: i32, _y: u32);
+    }
+}