June 2018 Update

Task/Permutations/Rust/permutations-2.rust

@@ -1,4 +1,5 @@
 use std::collections::VecDeque;
+
 fn permute<T, F: Fn(&[T])>(used: &mut Vec<T>, unused: &mut VecDeque<T>, action: &F) {
     if unused.is_empty() {
         action(used);
@@ -11,15 +12,7 @@ fn permute<T, F: Fn(&[T])>(used: &mut Vec<T>, unused: &mut VecDeque<T>, action:
     }
 }
 
-// Same as the vec! macro, but for VecDeques as well
-macro_rules! vec_deque {
-    ($($item:expr),*) => {{
-        let mut deque = ::std::collections::VecDeque::new();
-        $(deque.push_back($item);)*
-        deque
-    }}
-}
-
 fn main() {
-    permute(&mut Vec::new(), &mut vec_deque![1,2,3], &|perm| println!("{:?}", perm));
+    let mut queue = (1..4).collect::<VecDeque<_>>();
+    permute(&mut Vec::new(), &mut queue, &|perm| println!("{:?}", perm));
 }