add a peripherals! macro

for safe declaration of `Peripheral`s

closes #12

tests/cfail/peripherals-alias-1.rs

@@ -0,0 +1,68 @@
+// error-pattern: has already been defined
+
+#![feature(used)]
+
+#[macro_use]
+extern crate cortex_m_rtfm as rtfm;
+
+use rtfm::{C16, P0, P1};
+use device::interrupt::Exti0;
+
+peripherals!(device, {
+    GPIOA: Peripheral {
+        register_block: Gpioa,
+        ceiling: C1,
+    },
+    // WRONG: peripheral alias
+    GPIOA: Peripheral {
+        register_block: Gpioa,
+        ceiling: C2,
+    },
+});
+
+tasks!(device, {});
+
+fn init(_: P0, _: &C16) {}
+
+fn idle(_: P0) -> ! {
+    loop {}
+}
+
+fn j1(_task: Exti0, _prio: P1) {}
+
+// fake device crate
+extern crate core;
+extern crate cortex_m;
+
+mod device {
+    use cortex_m::peripheral::Peripheral;
+
+    pub const GPIOA: Peripheral<Gpioa> = unsafe { Peripheral::new(0x0) };
+
+    pub struct Gpioa;
+
+    pub mod interrupt {
+        use cortex_m::interrupt::Nr;
+
+        extern "C" fn default_handler<T>(_: T) {}
+
+        pub struct Handlers {
+            pub Exti0: extern "C" fn(Exti0),
+        }
+
+        pub struct Exti0;
+
+        pub enum Interrupt {
+            Exti0,
+        }
+
+        unsafe impl Nr for Interrupt {
+            fn nr(&self) -> u8 {
+                0
+            }
+        }
+
+        pub const DEFAULT_HANDLERS: Handlers =
+            Handlers { Exti0: default_handler };
+    }
+}

tests/cfail/peripherals-alias-2.rs

@@ -0,0 +1,74 @@
+// error-pattern: symbol `GPIOA` is already defined
+
+#![feature(const_fn)]
+#![feature(used)]
+
+#[macro_use]
+extern crate cortex_m_rtfm as rtfm;
+
+use rtfm::{C16, P0, P1};
+use device::interrupt::Exti0;
+
+peripherals!(device, {
+    GPIOA: Peripheral {
+        register_block: Gpioa,
+        ceiling: C1,
+    },
+});
+
+mod foo {
+    // WRONG: peripheral alias
+    peripherals!(device, {
+        GPIOA: Peripheral {
+            register_block: Gpioa,
+            ceiling: C2,
+        },
+    });
+}
+
+tasks!(device, {});
+
+fn init(_: P0, _: &C16) {}
+
+fn idle(_: P0) -> ! {
+    loop {}
+}
+
+fn j1(_task: Exti0, _prio: P1) {}
+
+// fake device crate
+extern crate core;
+extern crate cortex_m;
+
+mod device {
+    use cortex_m::peripheral::Peripheral;
+
+    pub const GPIOA: Peripheral<Gpioa> = unsafe { Peripheral::new(0x0) };
+
+    pub struct Gpioa;
+
+    pub mod interrupt {
+        use cortex_m::interrupt::Nr;
+
+        extern "C" fn default_handler<T>(_: T) {}
+
+        pub struct Handlers {
+            pub Exti0: extern "C" fn(Exti0),
+        }
+
+        pub struct Exti0;
+
+        pub enum Interrupt {
+            Exti0,
+        }
+
+        unsafe impl Nr for Interrupt {
+            fn nr(&self) -> u8 {
+                0
+            }
+        }
+
+        pub const DEFAULT_HANDLERS: Handlers =
+            Handlers { Exti0: default_handler };
+    }
+}