diff --git a/src/defines.cpp b/src/defines.cpp
index e07905c..ba70d41 100644
--- a/src/defines.cpp
+++ b/src/defines.cpp
@@ -148,6 +148,13 @@ struct {
                    "Wrong number of arguments: expected %d, got %d",    \
                    expected, actual)
 
+#define assert_arguments_length(expected, actual)                       \
+    do {                                                                \
+        if (expected != actual) {                                       \
+            create_wrong_number_of_arguments_error(expected, actual);   \
+        }                                                               \
+    } while(0)
+
 
 #define assert_type(_node, _type)                                       \
     do {                                                                \
diff --git a/src/memory.cpp b/src/memory.cpp
index 3446346..dd7e177 100644
--- a/src/memory.cpp
+++ b/src/memory.cpp
@@ -180,7 +180,7 @@ namespace Memory {
         return node;
     }
 
-    proc create_lisp_object_string(char* str) -> Lisp_Object* {
+    proc create_lisp_object_string(const char* str) -> Lisp_Object* {
         Lisp_Object* node = create_lisp_object();
         set_type(node, Lisp_Object_Type::String);
         node->value.string = create_string(str);