update examples

8 files changed, 84 insertions, 156 deletions

diff --git a/examples/full-syntax.rs b/examples/full-syntax.rs
index 184349b..20e8dfb 100644
--- a/examples/full-syntax.rs
+++ b/examples/full-syntax.rs
@@ -1,5 +1,4 @@
 //! A showcase of the `app!` macro syntax
-
 #![deny(unsafe_code)]
 #![feature(const_fn)]
 #![feature(proc_macro)]
@@ -8,7 +7,7 @@
 extern crate cortex_m_rtfm as rtfm;
 extern crate stm32f103xx;
 
-use rtfm::{app, Resource, Threshold};
+use rtfm::{app, Threshold};
 
 app! {
     device: stm32f103xx,
@@ -21,23 +20,30 @@ app! {
     },
 
     init: {
-        path: init_, // this is a path to the "init" function
+        // This is the path to the `init` function
+        //
+        // `init` doesn't necessarily has to be in the root of the crate
+        path: main::init,
     },
 
     idle: {
-        path: idle_, // this is a path to the "idle" function
+        // This is a path to the `idle` function
+        //
+        // `idle` doesn't necessarily has to be in the root of the crate
+        path: main::idle,
         resources: [OWNED, SHARED],
     },
 
     tasks: {
         SYS_TICK: {
             path: sys_tick,
-            priority: 1,
+            // If omitted priority is assumed to be 1
+            // priority: 1,
             resources: [CO_OWNED, ON, SHARED],
         },
 
         TIM2: {
-            // tasks are enabled, between `init` and `idle`, by default but they
+            // Tasks are enabled, between `init` and `idle`, by default but they
             // can start disabled if `false` is specified here
             enabled: false,
             path: tim2,
@@ -47,18 +53,22 @@ app! {
     },
 }
 
-fn init_(_p: init::Peripherals, _r: init::Resources) {}
+mod main {
+    use rtfm::{self, Resource, Threshold};
+
+    pub fn init(_p: ::init::Peripherals, _r: ::init::Resources) {}
 
-fn idle_(t: &mut Threshold, mut r: idle::Resources) -> ! {
-    loop {
-        *r.OWNED != *r.OWNED;
+    pub fn idle(t: &mut Threshold, mut r: ::idle::Resources) -> ! {
+        loop {
+            *r.OWNED != *r.OWNED;
 
-        if *r.OWNED {
-            if r.SHARED.claim(t, |shared, _| **shared) {
-                rtfm::wfi();
+            if *r.OWNED {
+                if r.SHARED.claim(t, |shared, _| **shared) {
+                    rtfm::wfi();
+                }
+            } else {
+                r.SHARED.claim_mut(t, |shared, _| **shared = !**shared);
             }
-        } else {
-            r.SHARED.claim_mut(t, |shared, _| **shared = !**shared);
         }
     }
 }
diff --git a/examples/generics.rs b/examples/generics.rs
index 6c6e1d6..57c9b8e 100644
--- a/examples/generics.rs
+++ b/examples/generics.rs
@@ -1,5 +1,4 @@
 //! Working with resources in a generic fashion
-
 #![deny(unsafe_code)]
 #![feature(proc_macro)]
 #![no_std]
@@ -36,7 +35,7 @@ fn idle() -> ! {
     }
 }
 
-// a generic function to use resources in any task (regardless of its priority)
+// A generic function that uses some resources
 fn work<G, S>(t: &mut Threshold, gpioa: &G, spi1: &S)
 where
     G: Resource<Data = GPIOA>,
@@ -53,12 +52,12 @@ where
     });
 }
 
-// this task needs critical sections to access the resources
+// This task needs critical sections to access the resources
 fn exti0(t: &mut Threshold, r: EXTI0::Resources) {
     work(t, &r.GPIOA, &r.SPI1);
 }
 
-// this task has direct access to the resources
+// This task has direct access to the resources
 fn exti1(t: &mut Threshold, r: EXTI1::Resources) {
     work(t, r.GPIOA, r.SPI1);
 }
diff --git a/examples/modules.rs b/examples/modules.rs
deleted file mode 100644
index 6bdf8d9..0000000
--- a/examples/modules.rs
+++ /dev/null
@@ -1,76 +0,0 @@
-//! Using paths and modules
-#![deny(unsafe_code)]
-#![feature(const_fn)]
-#![feature(proc_macro)]
-#![no_std]
-
-extern crate cortex_m_rtfm as rtfm;
-extern crate stm32f103xx;
-
-use rtfm::app;
-
-app! {
-    device: stm32f103xx,
-
-    resources: {
-        static CO_OWNED: u32 = 0;
-        static ON: bool = false;
-        static OWNED: bool = false;
-        static SHARED: bool = false;
-    },
-
-    init: {
-        path: main::init,
-    },
-
-    idle: {
-        path: main::idle,
-        resources: [OWNED, SHARED],
-    },
-
-    tasks: {
-        SYS_TICK: {
-            path: tasks::sys_tick,
-            resources: [CO_OWNED, ON, SHARED],
-        },
-
-        TIM2: {
-            path: tasks::tim2,
-            resources: [CO_OWNED],
-        },
-    },
-}
-
-mod main {
-    use rtfm::{self, Resource, Threshold};
-
-    pub fn init(_p: ::init::Peripherals, _r: ::init::Resources) {}
-
-    pub fn idle(t: &mut Threshold, mut r: ::idle::Resources) -> ! {
-        loop {
-            *r.OWNED != *r.OWNED;
-
-            if *r.OWNED {
-                if r.SHARED.claim(t, |shared, _| **shared) {
-                    rtfm::wfi();
-                }
-            } else {
-                r.SHARED.claim_mut(t, |shared, _| **shared = !**shared);
-            }
-        }
-    }
-}
-
-pub mod tasks {
-    use rtfm::Threshold;
-
-    pub fn sys_tick(_t: &mut Threshold, r: ::SYS_TICK::Resources) {
-        **r.ON = !**r.ON;
-
-        **r.CO_OWNED += 1;
-    }
-
-    pub fn tim2(_t: &mut Threshold, r: ::TIM2::Resources) {
-        **r.CO_OWNED += 1;
-    }
-}
diff --git a/examples/nested.rs b/examples/nested.rs
index 92f90cb..7013170 100644
--- a/examples/nested.rs
+++ b/examples/nested.rs
@@ -2,7 +2,6 @@
 //!
 //! If you run this program you'll hit the breakpoints as indicated by the
 //! letters in the comments: A, then B, then C, etc.
-
 #![deny(unsafe_code)]
 #![feature(const_fn)]
 #![feature(proc_macro)]
@@ -46,9 +45,12 @@ app! {
 fn init(_p: init::Peripherals, _r: init::Resources) {}
 
 fn idle() -> ! {
-    // sets task `exti0` as pending
+    // A
+    rtfm::bkpt();
+
+    // Sets task `exti0` as pending
     //
-    // because `exti0` has higher priority than `idle` it will be executed
+    // Because `exti0` has higher priority than `idle` it will be executed
     // immediately
     rtfm::set_pending(Interrupt::EXTI0); // ~> exti0
 
@@ -58,64 +60,66 @@ fn idle() -> ! {
 }
 
 fn exti0(t: &mut Threshold, r: EXTI0::Resources) {
-    // because this task has a priority of 1 the preemption threshold is also 1
+    // Because this task has a priority of 1 the preemption threshold `t` also
+    // starts at 1
 
     let mut low = r.LOW;
     let mut high = r.HIGH;
 
-    // A
+    // B
     rtfm::bkpt();
 
-    // because `exti1` has higher priority than `exti0` it can preempt it
+    // Because `exti1` has higher priority than `exti0` it can preempt it
     rtfm::set_pending(Interrupt::EXTI1); // ~> exti1
 
-    // a claim creates a critical section
+    // A claim creates a critical section
     low.claim_mut(t, |_low, t| {
-        // this claim increases the preemption threshold to 2
-        // just high enough to not race with task `exti1` for access to the
+        // This claim increases the preemption threshold to 2
+        //
+        // 2 is just high enough to not race with task `exti1` for access to the
         // `LOW` resource
 
-        // C
+        // D
         rtfm::bkpt();
 
-        // now `exti1` can't preempt this task because its priority is equal to
+        // Now `exti1` can't preempt this task because its priority is equal to
         // the current preemption threshold
         rtfm::set_pending(Interrupt::EXTI1);
 
-        // but `exti2` can, because its priority is higher than the current
+        // But `exti2` can, because its priority is higher than the current
         // preemption threshold
         rtfm::set_pending(Interrupt::EXTI2); // ~> exti2
 
-        // E
+        // F
         rtfm::bkpt();
 
-        // claims can be nested
+        // Claims can be nested
         high.claim_mut(t, |_high, _| {
             // This claim increases the preemption threshold to 3
 
-            // now `exti2` can't preempt this task
+            // Now `exti2` can't preempt this task
             rtfm::set_pending(Interrupt::EXTI2);
 
-            // F
+            // G
             rtfm::bkpt();
         });
 
-        // upon leaving the critical section the preemption threshold drops to 2
-        // and `exti2` immediately preempts this task
+        // Upon leaving the critical section the preemption threshold drops back
+        // to 2 and `exti2` immediately preempts this task
         // ~> exti2
     });
 
-    // once again the preemption threshold drops to 1
-    // now the pending `exti1` can preempt this task
+    // Once again the preemption threshold drops but this time to 1. Now the
+    // pending `exti1` task can preempt this task
     // ~> exti1
 }
 
 fn exti1(_t: &mut Threshold, _r: EXTI1::Resources) {
-    // B, H
+    // C, I
     rtfm::bkpt();
 }
 
 fn exti2(_t: &mut Threshold, _r: EXTI2::Resources) {
-    // D, G
+    // E, H
     rtfm::bkpt();
 }
diff --git a/examples/one-task.rs b/examples/one-task.rs
index e1d598d..556177d 100644
--- a/examples/one-task.rs
+++ b/examples/one-task.rs
@@ -14,11 +14,11 @@ use rtfm::{app, Threshold};
 app! {
     device: stm32f103xx,
 
-    // Here resources are declared
+    // Here data resources are declared
     //
-    // Resources are static variables that are safe to share across tasks
+    // Data resources are static variables that are safe to share across tasks
     resources: {
-        // declaration of resources looks exactly like declaration of static
+        // Declaration of resources looks exactly like declaration of static
         // variables
         static ON: bool = false;
     },
@@ -31,20 +31,24 @@ app! {
     tasks: {
         // Here we declare that we'll use the SYS_TICK exception as a task
         SYS_TICK: {
-            // Path to the task *handler*
+            // Path to the task handler
             path: sys_tick,
 
             // This is the priority of the task.
             //
-            // 1 is the lowest priority a task can have.
-            // The maximum priority is determined by the number of priority bits
-            // the device has. This device has 4 priority bits so 16 is the
-            // maximum value.
+            // 1 is the lowest priority a task can have, and the maximum
+            // priority is determined by the number of priority bits the device
+            // has. `stm32f103xx` has 4 priority bits so 16 is the maximum valid
+            // value.
+            //
+            // You can omit this field. If you do the priority is assumed to be
+            // 1.
             priority: 1,
 
-            // These are the *resources* associated with this task
+            // These are the resources this task has access to.
             //
-            // The peripherals that the task needs can be listed here
+            // A resource can be a peripheral like `GPIOC` or a static variable
+            // like `ON`
             resources: [GPIOC, ON],
         },
     }
@@ -75,8 +79,10 @@ fn idle() -> ! {
 
 // This is the task handler of the SYS_TICK exception
 //
-// `r` is the resources this task has access to. `SYS_TICK::Resources` has one
-// field per every resource declared in `app!`.
+// `_t` is the preemption threshold token. We won't use it in this program.
+//
+// `r` is the set of resources this task has access to. `TIMER0_A1::Resources`
+// has one field per resource declared in `app!`.
 fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
     // toggle state
     **r.ON = !**r.ON;
diff --git a/examples/preemption.rs b/examples/preemption.rs
index 057e4fd..256b9bd 100644
--- a/examples/preemption.rs
+++ b/examples/preemption.rs
@@ -1,4 +1,4 @@
-//! Two tasks running at different priorities with access to the same resource
+//! Two tasks running at *different* priorities with access to the same resource
 #![deny(unsafe_code)]
 #![feature(const_fn)]
 #![feature(proc_macro)]
@@ -17,7 +17,7 @@ app! {
     },
 
     tasks: {
-        // the task `SYS_TICK` has higher priority than `TIM2`
+        // The `SYS_TICK` task has higher priority than `TIM2`
         SYS_TICK: {
             path: sys_tick,
             priority: 2,
@@ -45,7 +45,7 @@ fn idle() -> ! {
 fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
     // ..
 
-    // this task can't be preempted by `tim2` so it has direct access to the
+    // This task can't be preempted by `tim2` so it has direct access to the
     // resource data
     **r.COUNTER += 1;
 
@@ -55,10 +55,10 @@ fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
 fn tim2(t: &mut Threshold, mut r: TIM2::Resources) {
     // ..
 
-    // as this task runs at lower priority it needs a critical section to
+    // As this task runs at lower priority it needs a critical section to
     // prevent `sys_tick` from preempting it while it modifies this resource
     // data. The critical section is required to prevent data races which can
-    // lead to data corruption or data loss
+    // lead to undefined behavior
     r.COUNTER.claim_mut(t, |counter, _t| { **counter += 1; });
 
     // ..
diff --git a/examples/two-tasks.rs b/examples/two-tasks.rs
index 42b91e4..ea059a0 100644
--- a/examples/two-tasks.rs
+++ b/examples/two-tasks.rs
@@ -1,4 +1,4 @@
-//! Two tasks running at the same priority with access to the same resource
+//! Two tasks running at the *same* priority with access to the same resource
 
 #![deny(unsafe_code)]
 #![feature(const_fn)]
@@ -13,34 +13,25 @@ use rtfm::{app, Threshold};
 app! {
     device: stm32f103xx,
 
-    // Resources that are plain data, not peripherals
     resources: {
-        // Declaration of resources looks like the declaration of `static`
-        // variables
         static COUNTER: u64 = 0;
     },
 
+    // Both SYS_TICK and TIM2 have access to the `COUNTER` data
     tasks: {
         SYS_TICK: {
             path: sys_tick,
-            priority: 1,
-            // Both this task and TIM2 have access to the `COUNTER` resource
             resources: [COUNTER],
         },
 
-        // An interrupt as a task
         TIM2: {
-            // For interrupts the `enabled` field must be specified. It
-            // indicates if the interrupt will be enabled or disabled once
-            // `idle` starts
             path: tim2,
-            priority: 1,
             resources: [COUNTER],
         },
     },
 }
 
-// when data resources are declared in the top `resources` field, `init` will
+// When data resources are declared in the top `resources` field, `init` will
 // have full access to them
 fn init(_p: init::Peripherals, _r: init::Resources) {
     // ..
diff --git a/examples/zero-tasks.rs b/examples/zero-tasks.rs
index 1320167..9176103 100644
--- a/examples/zero-tasks.rs
+++ b/examples/zero-tasks.rs
@@ -1,7 +1,7 @@
 //! Minimal example with zero tasks
-
 #![deny(unsafe_code)]
-#![feature(proc_macro)] // IMPORTANT always include this feature gate
+// IMPORTANT always include this feature gate
+#![feature(proc_macro)]
 #![no_std]
 
 extern crate cortex_m_rtfm as rtfm; // IMPORTANT always do this rename
@@ -15,7 +15,7 @@ use rtfm::app;
 // This macro will expand to a `main` function so you don't need to supply
 // `main` yourself.
 app! {
-    // this is a path to the device crate
+    // this is the path to the device crate
     device: stm32f103xx,
 }
 
@@ -28,20 +28,14 @@ fn init(p: init::Peripherals) {
     p.GPIOA;
     p.RCC;
     // ..
-
-    // You'll hit this breakpoint first
-    rtfm::bkpt();
 }
 
 // The idle loop.
 //
-// This runs afterwards and has a priority of 0. All tasks can preempt this
+// This runs after `init` and has a priority of 0. All tasks can preempt this
 // function. This function can never return so it must contain some sort of
 // endless loop.
 fn idle() -> ! {
-    // And then this breakpoint
-    rtfm::bkpt();
-
     loop {
         // This puts the processor to sleep until there's a task to service
         rtfm::wfi();