As a Common Lisp developer, the intro about Lisp strikes me as sort of mostly(?) true.

I would say in my experience we do actually "compile and execute" code, we can just do this incrementally and with less context switching because of the described workflow. But quite often there are in fact separate compile and run steps, it's just not at the whole program level (say, compile a function and run it or a calling function).

And despite how often it's shown off as a strength, redefining code during actual execution isn't quite that common, I think. Yes, it is done sometimes, but lots of programs don't really fit that paradigm in the first place. It can work well for e.g. some games or long running servers.

As for working in an image without source code: this seems like a terrible idea. You might do this for trivial, one off experiments, but in general you benefit from writing out and organizing your code early. I'm not even aware of a particularly easy or clean way to write out source code from an image as described. It could be done, but all the ways I can think of sound like more of a pain or mess than anything. Could just be my experience or I'm missing some neat feature of a commercial Lisp or something.

Note exactly the same but worth mentioning for C/C++ programmers out there: gdb can actually function as some sort of "cheap" live environment for C and C++

When stopped at a breakpoint, you can evaluate C/C++ expressions, modify state, call functions, and, with compile code, have GDB compile and execute new C/C++ code in the context of the running process:

   (gdb) set variable state->counter = 42
   (gdb) call recompute_state(state)

   (gdb) compile code
   > printf("counter = %d\n", state->counter);
   > do_something(state);
   > end

That makes for a surprisingly nice "REPL attached to a running C program" experience. You can poke at the heap, change variables, call into the existing code, and inject little bits of new code without restarting the process.

One use case I have fond memories of was implementing different trees structure and adding a print_dot function that printed the tree in .dot format and whenever I call the function from inside gdb, the xdot window would redraw with an updated tree graph.

I know it isn't really the same thing as a Lisp image where the injected code is become persistent but still nice to have

P.S: If you are trying gdb's tui for the first time and your program is still laden with print statements, you can ungarble the screen after a printf output with Ctrl+L or the refresh command

Gawd, that image-based approach to programming has never been mainstream because it creates a terrible mess.

Look at the nightmare notebooks you get from data scientists working in Python where they want to have their answers baked into a notebook that they can show to people and don't realize they need to separate code and data in version control and have a script you can run from top to bottom every single time if they want to put their skills on wheels.

i have learned a lot of interesting facts about haskell and lisp from this post. those facts make me want to run screaming away from trying to use either of them to develop software. My time with Haskell made me a better programmer and I bet that LLMs made some of the documentation more intelligible, but...

To be honest given the amount of structural obliteration you get out of GHC, image-based development sounds like a really bad idea. Haskell is such a weird and unintuitive language to understand from a systems perspective, because it's almost like you're restricted to writing macros for a language that you never directly see or interact with. The transformation from your source code to what the compiler spits out is can be highly non-local and unpredictable, even before you start introducing things like custom rewrite rules.

To me, I think the smart way to work with Haskell is the exact opposite of iteration. Work it out on paper, refine it, find the algebraic rules for it, refine it some more, and then start writing code once you know exactly what you're doing. I think giving in to the temptation to Just Start Writing Code is how you end up with opaque type spaghetti. That's just my feelings on it.

A language server doesn't have to involve live reloading, and normally doesn't? I feel like these are two orthogonal concerns. A language server is used for things like autocomplete and error highlighting.

I don't like them in principle because I believe the language should be more fully integrated with the IDE (like Eclipse does), but they do work, are a step up from syntax highlighting, and are practically a requirement if you have an NxM matrix of languages and IDEs.

I have always viewed the Emacs/Slime/CL development environment as being a more frictionless approach than the compile/link/execute approach of most other languages, but I get the impression there are people who evangelize "image-based coding" without having tried it out themselves.

The idea of not maintaining properly documented sources would terrify me.

As people point out, if you are not careful and execute arbitrary code in the REPL, your source and image can drift out of sync. When I was working on [1], I would go days without relaunching my image, but all the development was done by evaluating code in Emacs buffers and seeing the results right away. Occasionally, things got convoluted enough that I relaunched the process as a sanity check.

For me, the real benefit of iteratively modifying a live image lies in the sense of flow it engenders. I have not felt that sense in languages other than CL. I sometimes explain the feeling by saying than CL is the only language that I don't feel is fighting me.

[1] https://github.com/kaveh808/kons-9

I find it so fascinating how many programmers proudly declare how they don't use any IDE when incredibly sophisticated tools like solidworks or Synopsis are universally used in engineering

It is always cool to implement a powershell code in Linux style. Credits to the author of GHCup

Sounds genuinely horrible to program this way.

> A Lisp programmer does not need to …

Have you even seen R? Jupyter notebooks? The above sounds like a level of insanity beyond that.

The problem with checking things at runtime is that it’s an ever-moving target. Changed this? Now that other thing is out of sync. Changed that? Now the first thing is gone, and it came from far away so you can’t get it back in this session.

> They don’t have to restart the program on exceptions, because the condition system allows resuming the crashing code from anywhere in the stack after the system has been patched with a fix.

I'm "only" using Clojure (which some shall say is not a proper Lisp) and elisp (which is, well, elisp) but I catch every exceptions (including any yet uncaught ones) and I rarely need to restart the app. I've got an helper function to "restart" the app and I can pass a parameter: reset the state of the app or not (usually I don't and keep working with my current app state). As to the main process: I very rarely need to restart the JVM / get a new REPL.

The whole thing is basically a very, very, very long REPL session.

> A consequence of this way of working is that early in a Lisp project, there may not even be any source code to speak of. Instead, the evolving definition of the system exists only in the memory image of the running process and nowhere else.

Yes but be careful... At times this shall bite you: you've got this function or this new definition of that function that you only had working in the REPL and which is not in source code yet. I typically have tests and I run them, from another process, totally unrelated to the one I'm developing in, that I regularly run (not just when I commit): this helps catch at least the most serious "desynch" issues (where the Lisp source code doesn't correspond anymore to what's in the REPL).

> A Lisp programmer does not need to “switch over” to something else because they are already inside their program process. They never “compile and execute” the code because the code is already running and they edit it by hot-swapping code. They never restart in a debugger because they are already inside their program process and can inspect anything they want.

Yup it's all really very sweet. But really: those are all part of that family of languages and not a kludge added later on to the language.

Some people believe that because they have a console in the web dev tools in their browsers that can execute JavaScript code they've got the same thing as a Lisp. It's not anywhere near close to that.

> There’s no way to write Haskell that puts us inside the program process, so we will still need to restart in a debugger.

If you’re regularly using a debugger while developing ordinary Haskell programs, you’re doing something terribly wrong. Possibly writing in a very imperative style?

I have other reasons - mostly hiring competent engineers that deeply undertand the language. I can hire a competent SpringBoot engineer who can "fill out the form" and have a fast-enough API ready in a few days. Will it be beautiful and elegant? Probably not. Will it take traffic and get the data from the producer into a database reliably? Most likely.

From my time with Haskell, I learned to REALLY think about types. Like, REALLY. Having a type doc above every function that describes a curried path, is really cool. It made OCaml documentation (which I consider among the worst) make sense. (No shade at OCaml as a language. I LOVE it. But their docs aren't gonna win any awards)

What in particular makes you want to run away? I have found that the some what cliched(but true) comment that type signatures are mostly what you need for documentation even with heavy transformer code. I am some what confused by the post in question saying their repl experience in haskell was bad, I found the repl very powerful and worked well. The things I disliked of haskell the most was the package management, templating, issues around lazy eval, program start up time, program performance (particularly memory size) and some library's being overly based on some abstract mathematical model for little benefit and lots of cost and less flexibility and template haskell again because I really hate it. working on a common lisp project at the moment and it's quite nice thought he package manager story is a little bad in the very opposite direction to haskell in that it's too bare bones (quicklisp) but it's pretty easy to just git clone repos you want and use asdf to load them (asdf is a little weird to start but when you understand the whole load system repo stuff and central-registry variable your good to go and build what ever you want around it.

Another annoying thing with common lisp is when macros badly expand that can be tricky to debug.

  [0] https://www.quicklisp.org/beta/bundles.html
  [1] https://github.com/fosskers/vend
  [2] https://github.com/ocicl/ocicl
  [3] https://github.com/fukamachi/qlot

my favorite part of Haskell is that it's thorny which keeps bads away. like a good washout course in college. keeps the community "pure" kek

Completely agree, having worked with engineers and scientists for a large part of my career.

Programming is still in this goofy phase as a profession/industry where lots of practitioners interpret suffering and complexity and difficulty as signals of underlying quality.

There are still large numbers of programmers who see advances in human-computer interaction and tools as basically childish, because what matters to them is the feeling of machismo they get while programming, rather than whether their efforts make their users more successful.

See the pushback against IDEs (as you said), syntax highlighting (“syntax highlighting is for children”), Rust (“_I_ know how to manage memory, everyone else is an idiot who needs to git gud”), types generally (“_I_ don’t make type errors”). Even high level languages and garbage collection were met with similar derision when they were going mainstream. There are so many examples of this throughout the history of programming.

If something is hard to do, or resulted in something impressively complex rather than something underwhelmingly simple, it must be good.

Basically, we’re still a very immature profession and it’ll take time before we shed the “the most important thing about programming is that I get to be a wizard” stuff. The users care that the bridge doesn’t fall down when they drive over it. The users don’t care whether designing the bridge made me feel powerful and wizardly because I used a crayon rather than Solidworks.

I don’t like LSPs. They’re slow and bloated. I’ve been using clangd but I think I’ll stop. It’s slow as molasses. It constantly tries to insert headers into source files that cause compilation issues. There are easier and faster ways to jump to definitions.

I don’t use LSPs with Haskell anymore. I work on multiple projects which use different versions of GHC and the base library which means having multiple LSPs installed for each one. Trying to get eMacs to reliably detect which project is using which version is not something I have been able to figure out. Plus it’s slow and uses way too much memory.

At current job I’m doing C# and man does the ecosystem there really push you to use an IDE. Most of my org uses Rider. I find it just as fascinating that people actually like using tools like it. Too bad it doesn’t have a decent text editor built in.

You're phrasing this as if using an IDE was always an advantage, but unfortunately this isn't always the case:

-IDEs are more resources hungry, I remember when trying to use CLion on a big C++ codebase, until increasing the garbage collector maximum heap size all I had was a blank screen, after it was just unusably slow...

-even when IDE work, LSP for C++ codebase aren't very good, for example the caller hierarchy is usually very incomplete..

-I remember having been asked quite a few times, about "how do I use the IDE's integrated debugger to debug a target which was available only through ssh and then you had to telnet from one board to another?" My answer? Use gdb.

That said, I use VSCode now because its multiple tab handling is very nice, but I use it mostly as a glorified text editor (not by choice but because C++ is really IDE's unfriendly).

The language dominates the tooling. Real C programmers probably can't imagine doing real programming without gdb and valgrind. Real Java programmers probably can't imagine doing real programming with gdb and valgrind.

every tool present in an IDE is available elsewhere. it’s not that the IDE-avoidant aren’t using sophisticated tools, they just aren’t using them packaged up in a single application.

I've used IDEs from time to time, but they don't fit how I like to work.

Sometimes I work on my desktop, but most of my work is on a dev server. Some of my work is on my dedicated server at a budget host. I am not interested in an IDE that runs on my desktop and uses magic to edit files on my servers; properly configuring that with an eye towards security is not my idea of a good time. I'm not going to run an IDE on my server at hosting. I don't want to use multiple editors. The only sensible option is to use a terminal based editor for mostly everything. :p

Having used the same editor for programming for ~ 30 years at this point, I'm pretty good at it. When I use an IDE, it always feels more cumbersome ... sometimes it's valuable because I'm doing unfamiliar things anyway and the contextual assistance is sort of nice, but if I know what I'm doing, it gets in my way.

There's more than one way to do things, and if you want to use all the tools, go for it. I'm not trying to convince you not to, I'm just saying why it doesn't work for me.

They are using Emacs that's basically an IDE.

Because 'engineering' is a different field, with a different software ecosystem? What's fascinating about it? It's pretty blatantly obvious, engineers pay Dassault through the nose for Solidworks because there are no real alternatives. The same is not true for programming.

If there was a high quality CAD server that was interfaced via plugins for programmable 3D editing software like Blender, then we can start making comparisons. Fact of the matter is that this isn't the case, not like what programmers have gotten in the last 20 years. It's absolutely not impossible for such a thing to exist, it just doesn't. Building things like high quality heuristics for the topological naming problem is quite hard.

It doesn't help that almost every IDE in existence these days is also not a real IDE. Visual Studio, Xcode, Jetbrains, etc. are just a more rigid programmable text editor, they lack the "I", and quite a bit of the "E". Compare them with things like LispWorks and Delphi, and the difference is stark. For the former category of "DE"s, there are often tools which are just as high quality, if not higher quality, elsewhere. Speaking as someone that uses a very wide variety of tools, including the ones mentioned, there's really not a lot of point to them unless you just really like their specific UI/UX.