Homoiconicity anyone? Lisp is one of the oldest high-level programming languages, and it's still around.
Lean 3 was the least bloated theorem prover among Lean, Coq and Agda, and Lean 4 is the most bloated among this Big Three. This is very sad.
Personally, I stopped using Lean after the last update broke unification in a strange way again.
i tend to stick with agda for doing mathy programming. i kinda want lean4 to replace haskell at some point in the future as the workhorse production typed fp language.
https://github.com/dharmatech/symbolism.lean
Lean is astonishingly expressive.
Fun challenge. Unlike the author, I have nothing really to add.
I just wanted to say that "I did NOT write it with ..."
The most widely used variant of these proof assistants are probably formally verified compilers, like compcert, which are used in some highly regulated industries like aviation.
[0]: https://isabelle.systems/zulip-archive/stream/247541-Mirror.... and https://lean-lang.org/ (Cedar)
I've been wanting to adopt Lean for a project but wasn't sure about the speed. Nice to hear that it should be good on that front.
Well ... that is a trend that is driven largely by people who love types.
Not everyone shares that opinion. See ruby.
It is very hard to try to argue with people who love types. They will always focus on "types are great, every language must have them". They, in general, do not acknowledge trade-offs when it comes to type systems.
So the claim "tend to grow them" ... it is not completely wrong, but it also does not fully capture an independent want to add them. It comes ALWAYS from people who WANT types. I saw this happen "live" in ruby; I am certain this happened in python too.
> inevitably, people want to push types. even Go. C++ templates are the ultimate example. if it can be computed at compile time, at some point someone wants to, like Rust's ongoing constification.
And many people hate C++ templates. But comparing that language to e. g. ruby is already a losing argument. Languages are different. So are the trade-offs.
> dependent types can get you there. hence perfectable.
So the whole point about claiming a language is "perfectable", means to have types? I don't agree with that definition at all.
> most languages have no facility for this,
How about lisp?
> this lets you design APIs in layers and hide them behind syntax.
The language already failed hard syntax-wise. This is a problem I see in many languages - 99% of the language designers don't think syntax is important. Syntax is not the most important thing in the world, but to neglect it also shows a lack of understanding why syntax ALSO matters. But you can not talk about that really - I am 100% certain alok would disagree. How many people use a language also matters a LOT - you get a lot more momentum when there are tons of people using a language, as opposed to the global 3 or 4 using "lean".
Who else would add them, besides people who want them? I'm confused about what you're even claiming here. It sounds like you feel that there's a vocal minority of type enthusiasts who everyone else is just humoring by letting them bolt on their type systems.
I was wondering why lisp (and forth) were omitted from the initial list of languages named in the post.
I guess Scheme is in the list has ok macros.
#eval (UInt8.ofNat 256 : UInt8)
#eval (4 - 5 : Nat)
Nope! Both give 0.
On the other hand, array indices by default do require such a proof, i.e., this code produces a compile time error:
def x := #[1, 2, 3, 4]
#check x[7]
Lol
- Emacs: https://github.com/leanprover-community/lean4-mode
- Neovim: https://github.com/Julian/lean.nvim
I'm using the Emacs lean4-mode and it's pretty good.
But as someone who came of age in the AIM / ICQ / IRC days, it feels pretty normal. That's just how we wrote. I still fall into it by accident when the context is right and I'm not thinking about it (eg Slack at work). I hope youngsters aren't judging me for it.
if you wanted more than one sentence you sent one then wrote the other
it's painful to read longform
the victorians didn't give up on punctuation and regular english just because they had the telegraph
but surely its correlated
most of this comes from me noticing how funny sql looks with all the people trying to use caps all over the place as if anyones working in a place without syntax highlighting in 2026. sql is the wild west and everyones sql looks like shit there is no shame. i was told i needed to use caps more early on in sql and i lmfao'd, but i was new to the career and that scarred me. i write lower case sql just to spite others now and if you see something capitalized you know i meant it, but for the most part you have to pay me to use my shift key.
my trauma is now your trauma