Add iterate function

src/glearray.gleam

@@ -1,3 +1,5 @@
+import gleam/iterator.{type Iterator}
+
 pub type Array(a)
 
 @external(erlang, "glearray_ffi", "new")
@@ -64,3 +66,11 @@ pub fn insert(
 @external(erlang, "glearray_ffi", "insert")
 @external(javascript, "./glearray_ffi.mjs", "insert")
 fn do_insert(array: Array(a), index: Int, value: a) -> Array(a)
+
+pub fn iterate(array: Array(a)) -> Iterator(a) {
+  use index <- iterator.unfold(from: 0)
+  case at(array, index) {
+    Ok(element) -> iterator.Next(element, index + 1)
+    Error(_) -> iterator.Done
+  }
+}

test/glearray_test.gleam

@@ -1,6 +1,7 @@
 import gleam/list
 import gleam/function
 import gleam/result
+import gleam/iterator
 import gleeunit
 import gleeunit/should
 import glearray.{type Array}
@@ -100,6 +101,20 @@ pub fn insert_test() {
   |> should.equal(Ok([1, 2, 3, 20]))
 }
 
+pub fn iterate_test() {
+  iterate([])
+  iterate([1, 2, 3, 4])
+  iterate([0.4, 6.1, 99.9, -64.0])
+}
+
+fn iterate(list: List(a)) {
+  list
+  |> glearray.from_list
+  |> glearray.iterate
+  |> iterator.to_list
+  |> should.equal(list)
+}
+
 fn assert_empty(array: Array(a)) -> Array(a) {
   assert_length(array, 0)
   should.equal(array, glearray.new())