Initial project import

tools/v/vlib/arrays/reverse_iterator.v

@@ -0,0 +1,37 @@
+module arrays
+
+// ReverseIterator provides a convenient way to iterate in reverse over all elements of an array without allocations.
+// I.e. it allows you to use this syntax: `for elem in arrays.reverse_iterator(a) {` .
+pub struct ReverseIterator[T] {
+mut:
+	a []T
+	i int
+}
+
+// reverse_iterator can be used to iterate over the elements in an array.
+// i.e. you can use this syntax: `for elem in arrays.reverse_iterator(a) {` .
+pub fn reverse_iterator[T](a []T) ReverseIterator[T] {
+	return ReverseIterator[T]{
+		a: a
+		i: a.len
+	}
+}
+
+// next is the required method, to implement an iterator in V.
+// It returns none when the iteration should stop.
+// Otherwise it returns the current element of the array.
+@[direct_array_access]
+pub fn (mut iter ReverseIterator[T]) next() ?&T {
+	iter.i--
+	if iter.i < 0 {
+		return none
+	}
+	return unsafe { &iter.a[iter.i] }
+}
+
+// free frees the iterator resources.
+pub fn (iter &ReverseIterator[T]) free() {
+	// The array stored in the iterator is not owned by the iterator.
+	// It should not be freed, when the iterator goes out of scope.
+	// This is the reason, that this manual free method exists and is empty.
+}