Editing Extensible programming (section)

=== Extensible runtime ===
At runtime, extensible programming systems must permit languages to extend the set of operations that it permits. For example, if the system uses a [[byte-code]] interpreter, it must allow new byte-code values to be defined. As with extensible syntax, it is acceptable for there to be some (smallish) set of fundamental or intrinsic operations that are immutable. However, it must be possible to overload or augment those intrinsic operations so that new or additional behavior can be supported.