1 files changed, 50 insertions, 0 deletions
diff --git a/src/gleam/iterator.gleam b/src/gleam/iterator.gleam
index 5865646..c13a10e 100644
--- a/src/gleam/iterator.gleam
+++ b/src/gleam/iterator.gleam
@@ -386,6 +386,56 @@ pub fn map(over iterator: Iterator(a), with f: fn(a) -> b) -> Iterator(b) {
   |> Iterator
 }
 
+fn do_map2(
+  continuation1: fn() -> Action(a),
+  continuation2: fn() -> Action(b),
+  with fun: fn(a, b) -> c,
+) -> fn() -> Action(c) {
+  fn() {
+    case continuation1() {
+      Stop -> Stop
+      Continue(a, next_a) ->
+        case continuation2() {
+          Stop -> Stop
+          Continue(b, next_b) ->
+            Continue(fun(a, b), do_map2(next_a, next_b, fun))
+        }
+    }
+  }
+}
+
+/// Combines two interators into a single one using the given function.
+/// 
+/// If an iterator is longer than the other the extra elements are dropped.
+/// 
+/// This function does not evaluate the elements of the two iterators, the
+/// computation is performed when the resulting iterator is later run.
+/// 
+/// ## Examples
+/// 
+/// ```gleam
+/// let first = from_list([1, 2, 3])
+/// let second = from_list([4, 5, 6])
+/// map2(first, second, fn(x, y) { x + y }) |> to_list
+/// // -> [5, 7, 9]
+/// ```
+/// 
+/// ```gleam
+/// let first = from_list([1, 2])
+/// let second = from_list(["a", "b", "c"])
+/// map2(first, second, fn(i, x) { #(i, x) }) |> to_list
+/// // -> [#(1, "a"), #(2, "b")]
+/// ```
+/// 
+pub fn map2(
+  iterator1: Iterator(a),
+  iterator2: Iterator(b),
+  with fun: fn(a, b) -> c,
+) -> Iterator(c) {
+  do_map2(iterator1.continuation, iterator2.continuation, fun)
+  |> Iterator
+}
+
 fn do_append(first: fn() -> Action(a), second: fn() -> Action(a)) -> Action(a) {
   case first() {
     Continue(e, first) -> Continue(e, fn() { do_append(first, second) })