Compile more of stdlib

2 files changed, 64 insertions, 28 deletions

diff --git a/gen/list.erl b/gen/list.erl
index ae1ef24..2d87a6a 100644
--- a/gen/list.erl
+++ b/gen/list.erl
@@ -1,7 +1,7 @@
 -module(list).
 -include_lib("eunit/include/eunit.hrl").
 
--export([length/1, reverse/1, is_empty/1, has_member/2, head/1, tail/1, map/2, new/0, foldl/3, foldr/3]).
+-export([length/1, reverse/1, is_empty/1, has_member/2, head/1, tail/1, map/2, do_traverse/3, traverse/2, new/0, foldl/3, foldr/3]).
 
 length(A) ->
     erlang:length(A).
@@ -107,6 +107,41 @@ map_test() ->
         end([0, 4, 5, 7, 3])).
 -endif.
 
+do_traverse(List, Fun, Acc) ->
+    case List of
+        [] ->
+            {ok, reverse(Acc)};
+
+        [X | Xs] ->
+            case Fun(X) of
+                {ok, Y} ->
+                    do_traverse(Xs, Fun, [Y | Acc]);
+
+                {error, Error} ->
+                    {error, Error}
+            end
+    end.
+
+traverse(List, Fun) ->
+    do_traverse(List, Fun, []).
+
+-ifdef(TEST).
+traverse_test() ->
+    Fun = fun(X) -> case X =:= 6 orelse X =:= 5 of
+            true ->
+                {ok, X * 2};
+
+            false ->
+                {error, X}
+        end end,
+    _ = fun(Capture1) ->
+        expect:equal(Capture1, {ok, [10, 12, 10, 12]})
+    end(fun(Capture1) -> traverse(Capture1, Fun) end([5, 6, 5, 6])),
+    fun(Capture1) ->
+        expect:equal(Capture1, {error, 7})
+    end(fun(Capture1) -> traverse(Capture1, Fun) end([6, 5, 7, 3])).
+-endif.
+
 new() ->
     [].
 
diff --git a/src/list.gleam b/src/list.gleam
index 338ee3c..871c980 100644
--- a/src/list.gleam
+++ b/src/list.gleam
@@ -134,37 +134,38 @@ test map {
     |> expect:equal(_, [0, 8, 10, 14, 6])
 }
 
-// pub fn do_traverse(list, fun, acc) {
-//   case list {
-//   | [] -> Ok(reverse(acc))
-//   | [x | xs] ->
-//       case fun(x) {
-//       | Ok(y) -> do_traverse(xs, fun, [y | acc])
-//       | Error(error) -> Error(error)
-//       }
-//   }
-// }
+pub fn do_traverse(list, fun, acc) {
+  case list {
+  | [] -> Ok(reverse(acc))
+  | [x | xs] ->
+      case fun(x) {
+      | Ok(y) -> do_traverse(xs, fun, [y | acc])
+      | Error(error) -> Error(error)
+      }
+  }
+}
 
-// pub fn traverse(list, fun) {
-//   do_traverse(list, fun, [])
-// }
+pub fn traverse(list, fun) {
+  do_traverse(list, fun, [])
+}
 
-// test traverse {
-//   let fun = fn(x) {
-//     case x < 6 {
-//     | True -> Ok(x * 2)
-//     | False -> Error(x)
-//     }
-//   }
+test traverse {
+  let fun = fn(x) {
+    case x == 6 || x == 5 || x == 4 {
+    | True -> Ok(x * 2)
+    | False -> Error(x)
+    }
+  }
 
-//   let _ = [0, 4, 5, 6, 3]
-//     |> traverse(_, fun)
-//     |> expect:equal(_, Ok([0, 8, 10, 12, 6]))
+  let _ = [5, 6, 5, 6]
+    |> traverse(_, fun)
+    |> expect:equal(_, Ok([10, 12, 10, 12]))
+
+  [4, 6, 5, 7, 3]
+    |> traverse(_, fun)
+    |> expect:equal(_, Error(7))
+}
 
-//   [0, 4, 5, 7, 3]
-//     |> traverse(_, fun)
-//     |> expect:equal(_, Error(7))
-// }
 
 // pub fn drop(list, n) {
 //   case n <= 0 {