feat: new api try_collect for builtin/iter

builtin/builtin.mbti

@@ -226,6 +226,7 @@ impl Iter {
   take_while[T](Self[T], (T) -> Bool) -> Self[T]
   tap[T](Self[T], (T) -> Unit) -> Self[T] //deprecated
   to_array[T](Self[T]) -> Array[T]
+  try_collect[T, E : Error](Self[Result[T, E]]) -> Array[T]!E
 }
 impl[T : Show] Show for Iter[T]
 

builtin/iter.mbt

@@ -781,6 +781,20 @@ pub fn collect[T](self : Iter[T]) -> Array[T] {
   result
 }
 
+///|
+/// Collects the `Ok` elements of the iterator into an array,
+/// short circuiting if a `Err` is encountered.
+pub fn try_collect[T, E : Error](self : Iter[Result[T, E]]) -> Array[T]!E {
+  let result = []
+  for element in self {
+    match element {
+      Ok(x) => result.push(x)
+      Err(e) => raise e
+    }
+  }
+  result
+}
+
 ///|
 /// Iter itself is an iterator.
 /// so that it works with array spread operator. e.g, `[..iter]`

builtin/iter_test.mbt

@@ -312,6 +312,38 @@ test "collect" {
   assert_eq!(vec, ['1', '2', '3', '4', '5'])
 }
 
+test "try_collect Ok" {
+  let arr = ['1', '2', '3', '4', '5']
+  let iter : Iter[Result[Char, Error]] = Iter::new(
+    fn(yield_) {
+      for i = 0, len = arr.length(); i < len; i = i + 1 {
+        yield_(Ok(arr[i])) |> ignore
+      }
+      IterContinue
+    },
+  )
+  let vec = iter.try_collect?()
+  inspect!(vec, content="Ok(['1', '2', '3', '4', '5'])")
+}
+
+test "try_collect Err" {
+  let arr = ['1', '2', '3', '4', '5']
+  let iter : Iter[Result[Char, Error]] = Iter::new(
+    fn(yield_) {
+      for i = 0, len = arr.length(); i < len; i = i + 1 {
+        if i % 2 == 0 {
+          yield_(Ok(arr[i])) |> ignore
+        } else {
+          yield_(Err(Failure("odd"))) |> ignore
+        }
+      }
+      IterContinue
+    },
+  )
+  let vec = iter.try_collect?()
+  inspect!(vec, content="Err(moonbitlang/core/builtin.Failure.Failure)")
+}
+
 test "until" {
   // edge cases
   inspect!((0).until(10).take(100), content="[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]")

builtin/moon.pkg.json

@@ -11,7 +11,8 @@
     "moonbitlang/core/array",
     "moonbitlang/core/int64",
     "moonbitlang/core/uint",
-    "moonbitlang/core/json"
+    "moonbitlang/core/json",
+    "moonbitlang/core/error"
   ],
   "targets": {
     "int64_js.mbt": ["js"],