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Comment by preek | Hacker News Reader

If you want to compare Lisp Live Coding and you know Python, then let me compare it like this: How much faster can you get things done using something like ipython vs. a compiled static language like C(++/#) or Java? I don't want to go into a flamewar against the other languages, of course. Yet, if you favor an ipython repl against the compile/build/test cycle, then Lisp gives you just about the same order of magnitude more power.

I've done professional Python coding for 2.5 years, Ruby and JS for 7. I always believed that the REPL combined with those languages being dynamically typed can yield big advantages.

With a Lisp you can evaluate your code in real time in your editor. Also your app will re-load your code live without losing it's state. I've done that with Backends, Web Frontends and Mobile Apps. It's pretty awesome, not just compared to everything else^^

Take it for a spin and enjoy the ride(;

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To me, the live loading of code and repl is a two edged sword, and I'm not sure which side is sharper.

It sounds great to say "live coding" and whatnot, but it turns out that you very quickly get the repl into an unknown state where you aren't sure what version of what has been eval'd, and what temporary cruft is lying around changing how your program behaves.

A number of times I would find out that a bug I thought I squashed was actually still there, just hidden by some temporary "what-if" I had eval'd. The only way to know is to clean the workspace and reload everything.

This was recognized as problematic by the clojure community and "Component" methodologies were developed, along with namespace refreshing. It would be far less useable if not for this.

However, in a live production system, a blanket reload of anything kind of defeats the purpose of keeping it running. I don't think I'd ever try loading code on a live production system unless all the alternatives were worse than possibly messing up the state of the system.

It's nice to have the repl for investigating what's going on in production, for inspection. But I avoid any code reloading in a live system.

What are the bread-and-butter (aka not sexy and cutting edge, but mature and stable) lisps used for web development?

Well, I run my own companies, so I like the cutting edge - and we are using Clojure.

A good friend of mine works for one of those big consultancies, however, and they are currently rewriting the backend of the second biggest online retailer of the world and they are using Clojure, too^^

So either I'm getting too old for the sexy Startup business or Clojure is at the same time stable and fancy(;

SBCL (free), Allegro ($), probably some folks are still using clisp (which is a pretty cool Lisp, but almost defunct).

We built kindista.org with SBCL/Hunchentoot.

> With a Lisp you can evaluate your code in real time in your editor.

Technically there's nothing about Lisp that makes it uniquely suited for this; it's just that people developing tooling for most other languages have a tragic lack of imagination. Smalltalk, Forth, Factor, and to a degree Lua all support the same styles idiomatically, while Racket is a lisp, but it discourages this style.

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