Type check binary expressions

source/lexer.cpp

@@ -216,6 +216,10 @@ namespace elna::source
                 return "«proc»";
             case type::comparison_operator:
                 return "«comparison_operator»";
+            case type::hat:
+                return "«^»";
+            case type::at:
+                return "«@»";
         };
         assert(false);
     }