Test the scope of captured exception

README.md

@@ -177,7 +177,7 @@ like this:
 [Success] Ducks should quack!
 [Success] Denji should say 'Woof!'
 [Success] Class properties should be updated
-Ran 178 tests. Successful: 178. Failed: 0.
+Ran 179 tests. Successful: 179. Failed: 0.
 ```
 
 The tests themselves are written in Dry (while the `testDry` command is written in Scala). You can see the directory

src/main/scala/com/melvic/dry/interpreter/eval/EvalStmt.scala

@@ -13,7 +13,6 @@ import com.melvic.dry.aux.Nel.{Many, One}
 import com.melvic.dry.interpreter.Value.{Returned, Unit => VUnit}
 import com.melvic.dry.interpreter.eval.Context.implicits._
 import com.melvic.dry.interpreter.eval.Evaluate.Out
-import com.melvic.dry.interpreter.values.DException.NoArgDException
 import com.melvic.dry.interpreter.values.Value.{ToValue, Types}
 import com.melvic.dry.interpreter.values._
 import com.melvic.dry.interpreter.{Env, ModuleManager, Run}
@@ -155,8 +154,8 @@ private[eval] trait EvalStmt {
         .fold(
           {
             case One(failure @ Failure.Raised(_)) => handleException(failure)
-            case One(RuntimeError(kind, token, _)) =>
-              NoArgDException(kind, env).call(token)(Nil).flatMap { instance =>
+            case One(RuntimeError(kind, token, message)) =>
+              DException(kind, env).call(token)(Value.Str(message) :: Nil).flatMap { instance =>
                 handleException(Raised(instance.asInstanceOf[DInstance]))
               }
             case errors => Result.failAll(errors)

src/main/scala/com/melvic/dry/interpreter/values/DException.scala

@@ -13,6 +13,8 @@ class DException(val kind: Kind, val env: Env) extends DClass(kind.exceptionName
 
   override def arity = 1
 
+  // TODO: Add support for the other exception constructors. This would
+  //  make it more convenient to compare exception objects (no more direct message comparison)
   override def call(token: Token) = {
     case args @ ((message: Value.Str) :: _) =>
       super.call(token)(args).flatMap { case instance: DInstance =>
@@ -29,20 +31,6 @@ class DException(val kind: Kind, val env: Env) extends DClass(kind.exceptionName
 }
 
 object DException {
-  class NoArgDException(override val kind: Kind, override val env: Env) extends DException(kind, env) {
-    override def arity = 0
-
-    override def call(token: Token) = {
-      case Nil => super.call(token)(Value.Str(kind.exceptionName) :: Nil)
-      case _   => RuntimeError.invalidArgument(s"${Types.String}", typeOf(Value.Unit), token.line).fail
-    }
-  }
-
-  object NoArgDException {
-    def apply(kind: Kind, env: Env): NoArgDException =
-      new NoArgDException(kind, env)
-  }
-
   object Attributes {
     val Message: String = "__message__"
     val Kind: String = "__kind__"

stdlib/asserts.dry

@@ -16,7 +16,9 @@ def assert_error(description, expected_error, code) {
     try {
         code();
     } catch (error:) {
-        assert_equals(description, expected_error, error);
+        let expected_details = (expected_error.__kind__, expected_error.__message__);
+        let actual_details = (error.__kind__, error.__message__);
+        assert_equals(description, expected_details, actual_details);
     }
 }
 

tests/test_try_catch.dry

@@ -53,9 +53,22 @@ class TestTryCatch {
                 } catch (: IncorrectArityError) {} catch (: DivisionByZeroError) {}
             });
     }
+
+    def test_captured_error_scope() {
+        try {
+            10 / 0;
+        } catch (division_by_zero_error: DivisionByZeroError) {}
+
+        assert_error("Captured errors should not be visible outside of the catch block",
+            UndefinedVariableError("Undefined variable: division_by_zero_error"),
+            lambda() {
+                println(division_by_zero_error);
+            });
+    }
 }
 
 let try_catch = TestTryCatch();
 try_catch.test_single_catch();
 try_catch.test_multiple_catches();
-try_catch.test_no_match();
+try_catch.test_no_match();
+try_catch.test_captured_error_scope();