A REPL (Read-Eval-Print Loop) is an interactive environment, which can be used connected to your console, running application, language compiler and more, which gives you superpowers as an engineer 🦸🏼. Lisp dialects, more specifically Guile Scheme, have great support for this. I personally of course like to do this with Guix, Emacs, (Arei/Ares + sesman) you can get an ultimate extensible powerful editor experience, miles ahead of traditional IDEs 🐂 . It fundamentally changes the development workflow by eliminating the slow edit, save, compile, run cycle. Instead of writing a whole program and then running it to see what happens, you get a fast, conversational workflow. What does this mean for in practice? Incremental Development: Write, test, inspect, evaluate one function or even one line at a time. Get immediate feedback without running the entire app. Powerful Debugging: Forget adding print statements and restarting. You can pause, inspect objects, change values, and even redefine a broken function on the fly to test a fix in any environment (yes even in production, while running). Fast Prototyping & Learning: Instantly experiment with a new library or API. Just load it and start calling functions to see how they work, which is much faster than only reading documentation. When integrated into your code editor, you can execute any piece of code (a line, a selection, or a file) with a keyboard shortcut and see the result instantly, creating a seamless and powerful development experience.
First seen: 2026-07-21 13:27
Last seen: 2026-07-22 09:41