1 files changed, 14 insertions, 0 deletions
diff --git a/eval.c b/eval.c
index fc6e6d7..cb967c2 100644
--- a/eval.c
+++ b/eval.c
@@ -222,6 +222,19 @@ static enum RunStatus declare(struct Machine* machine, const struct Node* node)
     return RUN_DONE;
 }
 
+static enum RunStatus undeclare(struct Machine* machine, const struct Node* node)
+{
+    struct Variable* variable = find_variable(machine, node->name);
+    if (variable == NULL)
+    {
+        (void)complain(node, "cannot undeclare what was never declared");
+        return RUN_FAILED;
+    }
+
+    variable->declared = false;
+    return RUN_DONE;
+}
+
 static enum RunStatus emit(struct Machine* machine, const struct Node* node)
 {
     struct Type type;
@@ -261,6 +274,7 @@ static enum RunStatus execute_one(struct Machine* machine, const struct Node* no
     switch (node->kind)
     {
         case STMT_DECLARE: return declare(machine, node);
+        case STMT_UNDECLARE: return undeclare(machine, node);
         case STMT_EMIT: return emit(machine, node);
         case STMT_STATIC_ASSERT: return static_assert_statement(machine, node);
         default: break;