>In order for the interpreter's behavior to be different when presented with exactly the same input, it's necessary that the state of the interpreter has change

>In order for the interpreter's behavior to be different when presented with exactly the same input, it's necessary that the state of the interpreter has changed. What's the alternative? I guess that scoped changes is an option, that is you ask to alter the interpreter behavior only in a lexical scoped. Ruby has refinement in this spirit, though it’s not exactly operating at the same level as a require. Here is a related discussion that arised in Crystal community a few years ago: https://github.com/crystal-lang/crystal/issues/4439 https://github.com/crystal-lang/crystal/issues/4439