Implement unshift

src/core/List.pm

@@ -174,6 +174,13 @@ class List does Positional {
           !! fail 'Element shifted from empty list';
     }
 
+    method unshift(*@elems) {
+        while @elems.pop -> $e {
+            nqp::unshift($!items, $e)
+        }
+        self
+    }
+
     method sort($by = &infix:<cmp>) {
         # We defer to Parrot's ResizablePMCArray.sort method here.
         # Instead of sorting elements directly, we sort a Parcel of
@@ -298,6 +305,9 @@ multi sub pop(@a) { @a.pop }
 proto sub shift(|$) {*}
 multi sub shift(@a) { @a.shift }
 
+proto sub unshift(|$) {*}
+multi sub unshift(@a, *@elems) { @a.unshift: @elems }
+
 proto sub push(|$) {*}
 multi sub push(@a, *@elems) { @a.push: @elems }
 

t/spectest.data

@@ -485,7 +485,7 @@ S32-array/push.t
 # S32-array/rotate.t # err: Method 'rotate' not found for invocant of class 'Array'
 S32-array/shift.t
 # S32-array/splice.t # err: Could not find sub &splice
-# S32-array/unshift.t # err: Could not find sub &unshift
+S32-array/unshift.t
 # S32-basics/warn.t # err: "load_bytecode" couldn't find file 'Test/Util.pbc'
 # S32-container/zip.t # err: Cannot assign to a non-container
 S32-hash/exists.t
@@ -502,7 +502,7 @@ S32-io/file-tests.t
 # S32-io/IO-Socket-INET.t # err: Useless declaration of a has-scoped method in mainline
 S32-list/classify.t
 S32-list/create.t
-# S32-list/end.t # err: Method 'unshift' not found for invocant of class 'Array'
+S32-list/end.t
 # S32-list/first.t # err: Could not find sub &first
 S32-list/grep.t
 S32-list/join.t