Hello, I don't know if this is the right place to post this. Please redirect as needed. I've made a small Python interpreter in Python with runtime AST node semantics and edit-and-continue. I thought it could make prototyping language changes more easily and visualize usage before writing them in C. Its here: https://github.com/asrp/python_terp So, for example, redefining the for_stmt function in the right scope changes the behaviour of future for loops at runtime. Although from discussion I've read in PEPs, actual implementation always look like a non-issue (which seems like magic to me) so maybe no-one here actually needs this. (I really needed edit-and-continue for one of my projects but of course, running it in this extra interpreter is much too slow.) asrp