some safety checks

src/memory.cpp

@@ -151,11 +151,11 @@ namespace Memory {
         next_free_spot_in_string_memory = string_memory;
 
         // init nil
-        try nil = create_lisp_object();
+        try_void nil = create_lisp_object();
         set_type(nil, Lisp_Object_Type::Nil);
 
         // init t
-        try t = create_lisp_object();
+        try_void t = create_lisp_object();
         set_type(t, Lisp_Object_Type::T);
     }
 

src/parse.cpp

@@ -275,11 +275,14 @@ namespace Parser {
                 try ret = Memory::create_lisp_object_pair(
                     Memory::get_or_create_lisp_object_symbol("quasiquote"),
                     Memory::create_lisp_object_pair(result, Memory::nil));
-            else if (quoteType == ',')
+            else if (quoteType == ',') {
                 try ret = Memory::create_lisp_object_pair(
                     Memory::get_or_create_lisp_object_symbol("unquote"),
                     Memory::create_lisp_object_pair(result, Memory::nil));
+            }
+            if (ret) {
                 inject_scl(ret);
+            }
             return ret;
         }