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Comment by tyromaniac | Hacker News Reader

We wouldn't have need such barbaric things in a lisp world. :p

Personally I think/hope they would have earlier discoveries / more broad usage of the deterministic systems like nix etc, which are built upon functional principles of immutability etc.

Maybe the world would be guix/Hurd!

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Common Lisp is pretty much the opposite of what people think of as functional nowadays. You're constantly changing the image and everything is mutable.

Image saving isn't something that's done very often, in practice.

What is done in practice, for daily development use? Building the image in memory from source files at startup?

Typically, for development, one will start a clean image in the morning and load it up with a combination of newly compiled code and automatically cached previously compiled code. This is mostly invisible to the user unless something goes wrong with the cache and it has to be cleared. The unaware user could think they're recompiling everything every time.

Yes, that's quite fast. The files are kept in a version control system so you update from that first as well.

The use cases for images would be: delivery of applications to users, or (internally) delivery of some fixed set of underlying code that is used as a substrate for development but that wouldn't normally be changed by developers.

Normally, the developer has an image running all day, and does development and testing in it, but (unless needed for additional testing) doesn't save that image as a new binary that others can run.

I would presume there was a lot of mixing of imperative/functional in the 80s where this alt universe starts. I think the same type of world in which lisp machines would have become king would also be similar

yeah it's a strange aspect of that lisp era, it was born in mccarthy's recursive functions over recursive lists.. and then interactive development over global state added as a layer.

i would argue that lispers use of mutability was much more surgical and principled but maybe i'm biased

McCarthy's pure Lisp existed only on paper. The first Lisp that ran on a computer had mutable variables, as did Lisp 1.5, Maclisp, etc...

Immutability requires lots of copying and early computers didn't have much memory to spare...

fair point but from memory most of early programs in his paper were purely immutable in nature (tree recursion and substition), right ?

Yes but he also wrote this when describing the language:

> In addition to the facilities for describing S-functions, there are facilities for using S-functions in programs written as sequences of statements along the lines of FORTRAN (4) or ALGOL (5). These features will not be described in this article

hmm funny i completely missed that, i thought these traits were introduced a bit later

Yeah, all the common lispers I know are all about interacting with "live" programs as opposed to "dead", compiled ones. Nix takes the last live, mutable, reflectable part of the world of programmers today, the OS itself, and turns it into a dead program as well. So common lispers tend to hate Nix with a passion (as do Smalltalk users).

i'm a lisper, and i don't hate nix. i prefer guix, for sure, but i don't see this hatered you're talking about among other lispers either.

Common lisp isn't functional in that sense.

Sure the language might not be immutable but the lisp machine alt universe's "overton window" would I imagine be more functional then today's (JVM? maybe that's the qnalog?) reality.

When I learned (Common) Lisp at Georgia Tech in the summer of 1995, we were encouraged to make as many functions as possible purely functional, and if mutation was needed, to try to hide it within the bounds of a function.

So while Lisp may not be purely functional, the culture hewed that way.

That's interesting, because I had the opposite experience. I started getting into Lisp around 2004, but bounced off of the community because the culture I was experiencing hewed heavily toward imperative code and global variables in the name of efficiency.

I specifically remember the breaking point being third-party library where none of the functions had any parameters. Instead, everything was controlled by using dynamic binding to adjust the variables within the functions. Various forum members kept praising its beauty and elegance, but I found it needlessly confusing.

I have a soft spot for the Lisp family of languages. I've been using Emacs for almost thirty years and have used both Scheme and Clojure in production. However, my experiences back in 2006 have left me with a permanent bias against Common Lisp.

> Personally I think/hope they would have earlier discoveries / more broad usage of the deterministic systems like nix etc, which are built upon functional principles of immutability etc.

Yeah, that, uh, doesn't sound like Lisp

https://guix.gnu.org/

Yeah, I mean, I know it exists, but the mythology of Lisp is built around "I can drop into a REPL and execute arbitrary code on a production system and that is a good thing"

As opposed to our wonderful world where everyone does the same with unchecked binaries or obfuscated/minified JS?

To me the mythology of lisp (from my mostly outsider perspective) is more like "make everything a interoperable DSL" (although if this is what you were describing with your sentence then thats fair enough)

You can with Guix, just save your config in a new deployment for a new boot.

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