implemented calls

lib/interpreter.ml

@@ -75,13 +75,34 @@ let rec interpret_expr (env : environment) (expr_node : expr_node) :
       match (op, lox_value_to_bool left) with
       | And, false | Or, true -> Ok left (* short circuit *)
       | _ -> interpret_expr env right)
+  | Call { callee; args } -> (
+      let* callee = interpret_expr env callee in
+      let f (acc : (lox_value list, runtime_error) result) (arg : expr_node) :
+          (lox_value list, runtime_error) result =
+        match acc with
+        | Ok acc ->
+            let* arg = interpret_expr env arg in
+            Ok (arg :: acc)
+        | Error e -> Error e
+      in
+      let* args = List.fold_left f (Ok []) args in
+      let args = List.rev args in
+      let args_s =
+        List.fold_left (fun acc value -> acc ^ " " ^ string_of_lox_value value) "" args
+      in
+      Printf.eprintf "Called %s with args%s\n%!" (string_of_lox_value callee) args_s;
+      match callee with
+      | _ ->
+          let msg = Printf.sprintf "%s object is not callable" (type_string_of_lox_value callee) in
+          RuntimeError.make pos msg |> Result.error)
 
 let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runtime_error) result =
   let { pos; stmt } = stmt_node in
   ignore pos;
   match stmt with
   | Expr expr ->
-      let* _ = interpret_expr env expr in
+      let* value = interpret_expr env expr in
+      ignore value;
       Ok ()
   | Break -> RuntimeError.break () |> Result.error
   | Continue -> RuntimeError.continue () |> Result.error
@@ -101,7 +122,7 @@ let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runt
       let rec _interpret stmts =
         match stmts with
         | stmt :: tail ->
-            let* _ = interpret_stmt env stmt in
+            let* () = interpret_stmt env stmt in
             _interpret tail
         | [] -> Ok ()
       in
@@ -123,7 +144,7 @@ let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runt
       else Ok ()
   | For { init; cond; update; body } ->
       let env = Env.enter env in
-      let* _ = init |> Option.map (interpret_stmt env) |> Option.value ~default:(Ok ()) in
+      let* () = init |> Option.map (interpret_stmt env) |> Option.value ~default:(Ok ()) in
       let eval_cond () =
         cond
         |> Option.map (interpret_expr env)
@@ -139,7 +160,8 @@ let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runt
           let result = interpret_stmt env body in
           match result with
           | Ok () | Error Continue ->
-              let* _ = do_update () in
+              let* value = do_update () in
+              ignore value;
               loop ()
           | Error Break -> Ok ()
           | Error e -> Error e