[hypersoar]

For me, the killer feature of Clojure is "REPL driven development". The ability to get rapid feedback as you build things up is incredible. I'll make a comment form and evaluate expressions within it to try things out as I go. By the time I've written any reasonably complex function, all of the pieces have been tested on various examples. Once I'm done, the comment form leaves a helpful record of my thought process.

If you're wondering what's so great about the Clojure repl (and other lisp repls) in particular, the thing is that you never have to actually type something into it. You can run evaluations from the code file itself. The structure of lisps makes it clear exactly which code you want to evaluate. To do this, I use the excellent CIDER package for emacs. I understand Calva for VS Code and Cursive for IntellJ offer similar functionality.

Here's a good talk on what this looks like:

https://www.youtube.com/watch?v=gIoadGfm5T8

[pedrodelfino]

I kind of agree with you. I used to work with Common Lisp in a Desktop App (Nyxt browser). I had some fun playing with Racket. And I love Emacs. So, I am already into the Lisp idea. But, I was kind of disappointed with Clojure which is new in my life and has been used in my current job. Maybe you have a backend bias in your testimony?

I have been working with ClojureScript (re-frame and reagent) on front-end stuff and, unfortunately, the REPL does not seem to help me that much on my workflow. I miss the REPL driven development, by the way... The real "interactive programming" seems to happen on Chrome Dev Tools + Browser's reactions to Chrome Dev Tools tweaks on the UI + (lastly) changes on the source code via the editor (Emacs in my case).

Namespaces as prefix of invocations on the REPL are not that trustworthy on ClojureScript, apparently. It could also be that I am a noob and I missed something, so... How do you feel about ClojureScript?

[drikerf]

Don't know about your exact environment but I've structured my code so most of it is in .cljc files which can be evaluated in browser and on server. This allows me to evaluate/test/run things easily in the emacs repl.

For view code I think hot reloading has been a great thing with Clojure/Script too. Everything is reloaded properly and the state remains.

[yenda]

You can have a cljs repl as well, and you can open an alert in the browser from it like you'd do in the console

[freshhawk]

I have basically the same experience doing cljs dev that I do with clj dev, when it comes to being REPL-driven.

I know that the setup for cljs is a bit more involved and things will break sometimes (putting a browser in the loop will do that). I have dev tools open ... but I use it less and less, between hot-reloading and a data browser (portal or reveal) hooked up to the clojurescript repl I only use dev-tools stuff occasionally (the network tab is still very important of course).

It does sound like you are missing something, I'd try out one of the shadow-cljs example projects or walkthroughs to see what an example setup includes as features to see what you might be missing.

[jdminhbg]

Have you tried Figwheel[0]? This is how I maintain a REPL into a browser-based CLJS application under development.

[0]: https://figwheel.org

[hypersoar]

I don't want to overstate my experience--I've used neither professionally. But I think it's true that the repl is better with Clojure than with Clojurescript. Cider with shadow-cljs is very nice but not quite as well-supported as vanilla. Plus, the very fact that you're producing code to be rendered by a browser pushes the work you do on the pure data level, where the repl really shines, towards the background.

[staticelf]

I don't understand, doesn't most languages these days have a REPL?

[solarmist]

If you haven't used a lisp or lisp clone, it's hard to describe fully. Still, the fact that you can trivially replace and reload modules in running code or being able to fix a bug in a function and resubmit the input to the function from the stack trace is amazing ergonomically.

In the same way that most languages have lambdas, it's very different from being able to trivially compose functions into new functions. (This one I can't even describe well, but if you try and write SICP exercises in a lisp vs. python, the difference is obvious.

[staticelf]

Do you have any examples of this? Like a video on youtube or similar?

I have used Clojure before very lightly but I didn't really use the REPL in this way. I rather used it the same way I use it for javascript, python or any other language.

[solarmist]

This seems like a neat one. https://youtu.be/6pMyhrDcMzw

[seer-zig]

Java has `jshell`.

[bcrosby95]

Just like C++ has automatic memory management because of the existence of smart pointers.