Ep 099: REPL Your World

Functional Design in Clojure

Each week, we discuss a different topic about Clojure and functional programming.

If you have a question or topic you'd like us to discuss, tweet @clojuredesign, send an email to [e-mail], or join the #clojuredesign-podcast channel on the Clojurians Slack.

This week, the topic is: "taking the REPL beyond your application". We free our REPL to explore and automate the world around us.

Our discussion includes:

• What are the different ways of working with the REPL?
• How can you be more productive by using the REPL?
• What is the connected editor?
• How to use the REPL beside writing code for your application.
• What is often missing from API docs.
• Moving from bash to Clojure.
• Using the REPL for exploration.
• What is a "fiddle" approach to using the REPL? What is it good for?
• Why should you use your editor for non-coding activities?
• How to save time when you're stuck with manual testing.
• Interacting with databases.
• When is the REPL better than a script?
• How a REPL is like a bash prompt, and how it's not.
• What supports the supporting activities of software development?
• Using the REPL as your application interface.
• Migrating data using the REPL.
• Why your REPL is a natural place for difficult to access resources.
• Why the REPL saves you from extra coding.

Selected quotes:

• "We share because we care."
• "The connected editor is an interface to productivity."
• "I like to call it whiplash-driven development because it's so fast that you literally have no time between when you write the code to when you execute it. You're just blown back by the productivity!"
• "This is a Clojure Podcast, so I bet you know where this is going."
• "The REPL as a window into another system."
• "I actually wrote the API, so I know how it should behave...but not how it does!"
• "Isn't that one of the goals of your programming language and experience: to spend less time doing the things that are really mundane and repetitive and more time actually doing new things?"
• "I don't want to just let that go into the history file. I want to save it someplace more important."
• "I have all of the power of Clojure before the query and then after the query. I don't have to trick psql to write that data out somewhere so I can read it in my REPL. It's already there!"
• "It's not that there aren't other ways to do this. That's not the point. The point is that all of a sudden you realize there's a lot of interactive exploration and processing and task automation you can do from the REPL because you don't need to write a script to do it."
• "You can just execute a form, and boom! It's off. It's running."
• "But then, I was like 'Wait, there's got to be a better way!' You know, infomercial style."
• "It's functional programming, so we're going to talk about composition. It'll happen."
• "Whoa! The REPL could be a terminal! A super powerful terminal into a vast warehouse of data, and I can slice it and dice it all sorts of different ways and discover things."
• "The REPL is just a way of doing structured execution very rapidly and very flexibly."
• "With the REPL, every function or form is a potential entry point. You can have all kinds of entry points."
• "The malleability of it is its power."

Links:

• REPL Series
  • Ep 012: Embrace the REPL
  • Ep 013: Connect the REPL
  • Ep 014: Fiddle with the REPL
• Composition Series
  • Ep 093: Waffle Cakes (first episode)
  • Ep 098: Composed Learnings (summary episode)
• Talks mentioned
  • "Running With Scissors: Live Coding With Data" by Stuart Halloway. Presented at Strange Loop 2018.
  • "Data Science in Clojure" by Soren Macbeth. Presented at Clojure/West 2015.
• Projects mentioned
  • Nate's tabl project
  • Nate's guide: Developing Clojure in Vim (2023 edition)
  • Conjure for Neovim
  • next.jdbc
  • Honey SQL