1 files changed, 173 insertions, 0 deletions
diff --git a/gen/src/list.erl b/gen/src/list.erl
new file mode 100644
index 0000000..b606f22
--- /dev/null
+++ b/gen/src/list.erl
@@ -0,0 +1,173 @@
+-module(list).
+-compile(no_auto_import).
+
+-export([length/1, reverse/1, is_empty/1, contains/2, head/1, tail/1, filter/2, map/2, traverse/2, drop/2, take/2, new/0, append/2, flatten/1, fold/3, fold_right/3, find/2]).
+
+length(A) ->
+    erlang:length(A).
+
+reverse(A) ->
+    lists:reverse(A).
+
+is_empty(List) ->
+    List =:= [].
+
+contains(List, Elem) ->
+    case List of
+        [] ->
+            false;
+
+        [Head | Rest] ->
+            Head =:= Elem orelse contains(Rest, Elem)
+    end.
+
+head(List) ->
+    case List of
+        [] ->
+            {error, empty};
+
+        [X | _] ->
+            {ok, X}
+    end.
+
+tail(List) ->
+    case List of
+        [] ->
+            {error, empty};
+
+        [_ | Xs] ->
+            {ok, Xs}
+    end.
+
+do_filter(List, Fun, Acc) ->
+    case List of
+        [] ->
+            reverse(Acc);
+
+        [X | Xs] ->
+            NewAcc = case Fun(X) of
+                true ->
+                    [X | Acc];
+
+                false ->
+                    Acc
+            end,
+            do_filter(Xs, Fun, NewAcc)
+    end.
+
+filter(List, Fun) ->
+    do_filter(List, Fun, []).
+
+do_map(List, Fun, Acc) ->
+    case List of
+        [] ->
+            reverse(Acc);
+
+        [X | Xs] ->
+            do_map(Xs, Fun, [Fun(X) | Acc])
+    end.
+
+map(List, Fun) ->
+    do_map(List, Fun, []).
+
+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, []).
+
+drop(List, N) ->
+    case N =< 0 of
+        true ->
+            List;
+
+        false ->
+            case List of
+                [] ->
+                    [];
+
+                [_ | Xs] ->
+                    drop(Xs, N - 1)
+            end
+    end.
+
+do_take(List, N, Acc) ->
+    case N =< 0 of
+        true ->
+            reverse(Acc);
+
+        false ->
+            case List of
+                [] ->
+                    reverse(Acc);
+
+                [X | Xs] ->
+                    do_take(Xs, N - 1, [X | Acc])
+            end
+    end.
+
+take(List, N) ->
+    do_take(List, N, []).
+
+new() ->
+    [].
+
+append(A, B) ->
+    lists:append(A, B).
+
+do_flatten(Lists, Acc) ->
+    case Lists of
+        [] ->
+            Acc;
+
+        [L | Rest] ->
+            do_flatten(Rest, append(Acc, L))
+    end.
+
+flatten(Lists) ->
+    do_flatten(Lists, []).
+
+fold(List, Acc, Fun) ->
+    case List of
+        [] ->
+            Acc;
+
+        [X | Rest] ->
+            fold(Rest, Fun(X, Acc), Fun)
+    end.
+
+fold_right(List, Acc, Fun) ->
+    case List of
+        [] ->
+            Acc;
+
+        [X | Rest] ->
+            Fun(X, fold_right(Rest, Acc, Fun))
+    end.
+
+find(Haystack, F) ->
+    case Haystack of
+        [] ->
+            {error, not_found};
+
+        [X | Rest] ->
+            case F(X) of
+                {ok, X1} ->
+                    {ok, X1};
+
+                _ ->
+                    find(Rest, F)
+            end
+    end.