Added support for trailing comma in the arr! macro

Author: regexident

src/arr.rs

@@ -26,30 +26,30 @@ pub type Inc<T, U> = <U as AddLength<T, U1>>::Output;
 #[macro_export]
 macro_rules! arr_impl {
     ($T:ty; $N:ty, [$($x:expr),*], []) => ({
-	unsafe { $crate::transmute::<_, $crate::GenericArray<$T, $N>>([$($x),*]) }
+        unsafe { $crate::transmute::<_, $crate::GenericArray<$T, $N>>([$($x),*]) }
     });
     ($T:ty; $N:ty, [], [$x1:expr]) => (
         arr_impl!($T; $crate::arr::Inc<$T, $N>, [$x1 as $T], [])
     );
     ($T:ty; $N:ty, [], [$x1:expr, $($x:expr),+]) => (
-        arr_impl!($T; $crate::arr::Inc<$T, $N>, [$x1 as $T], [$($x),*])
+        arr_impl!($T; $crate::arr::Inc<$T, $N>, [$x1 as $T], [$($x),+])
     );
     ($T:ty; $N:ty, [$($y:expr),+], [$x1:expr]) => (
-        arr_impl!($T; $crate::arr::Inc<$T, $N>, [$($y),*, $x1 as $T], [])
+        arr_impl!($T; $crate::arr::Inc<$T, $N>, [$($y),+, $x1 as $T], [])
     );
     ($T:ty; $N:ty, [$($y:expr),+], [$x1:expr, $($x:expr),+]) => (
-        arr_impl!($T; $crate::arr::Inc<$T, $N>, [$($y),*, $x1 as $T], [$($x),*])
+        arr_impl!($T; $crate::arr::Inc<$T, $N>, [$($y),+, $x1 as $T], [$($x),+])
     );
 }
 
 /// Macro allowing for easy generation of Generic Arrays.
 /// Example: `let test = arr![u32; 1, 2, 3];`
 #[macro_export]
 macro_rules! arr {
-    ($T:ty;) => ({
+    ($T:ty; $(,)*) => ({
         unsafe { $crate::transmute::<[$T; 0], $crate::GenericArray<$T, $crate::typenum::U0>>([]) }
     });
-    ($T:ty; $($x:expr),*) => (
+    ($T:ty; $($x:expr),* $(,)*) => (
         arr_impl!($T; $crate::typenum::U0, [], [$($x),*])
     );
     ($($x:expr,)+) => (arr![$($x),*]);

tests/arr.rs

@@ -0,0 +1,27 @@
+#[macro_use]
+extern crate generic_array;
+extern crate typenum;
+
+#[test]
+fn empty_without_trailing_comma() {
+    let ar = arr![u8; ];
+    assert_eq!(format!("{:x}", ar), "");
+}
+
+#[test]
+fn empty_with_trailing_comma() {
+    let ar = arr![u8; , ];
+    assert_eq!(format!("{:x}", ar), "");
+}
+
+#[test]
+fn without_trailing_comma() {
+    let ar = arr![u8; 10, 20, 30];
+    assert_eq!(format!("{:x}", ar), "0a141e");
+}
+
+#[test]
+fn with_trailing_comma() {
+    let ar = arr![u8; 10, 20, 30, ];
+    assert_eq!(format!("{:x}", ar), "0a141e");
+}