Sebastian Ullrich

The compiler warnings about me have been greatly exaggerated

@freekwiedijk @yury_kudryashov After `update` you're on a recent Mathlib version so it's not unexpected that things work differently from last time. If you follow the guide I linked to, it shouldn't matter what version you currently have.

@derKha @yury_kudryashov I don't remember. The website? Floris and/or Mario? It certainly is Lean 4. And I'm reasonably convinced at the time everything was set up okay. Creating a fresh project *did* work fine before.

error: 'mathlib.Cache.Main' ▸ 'Cache.Requests' ▸ 'Lean.Data.Json.Parser': no such file or directory (error code: 2) file: ./././Lean/Data/Json/Parser.lean @leanprover 😢

@freekwiedijk @yury_kudryashov Where did you get the instructions from? The ones at #creating-a-lean-project" target="_blank" rel="nofollow noopener">leanprover-community.github.io/install/projec… make sure to start from a known Lean version

@yury_kudryashov I don't remember. I installed vscode and lean some time ago, and then everything seemed to work. But then I was busy with other things, and didn't use it. So now I tried to have another go at it, with this failure at the very start.

@sgraf1337 @TechnoEmpress @rob_rix who the hell thought a low character limit was a good idea. i'm going back to mastodon.

@sgraf1337 @TechnoEmpress @rob_rix So effectively it's like working with an actually typed tree structure, except we currently don't have exhaustiveness checking in quotation matches (but it's not even clear how that should work in case of partial syntax trees from failed parses)

We are excited to share the news of the Lean Focused Research Organization (FRO): lean-fro.org! A new nonprofit dedicated to advancing the Formal Mathematics revolution, we aim to tackle the challenges of scalability, usability, and proof automation in Lean.

@freekwiedijk @leanprover "syntax"

@derKha @leanprover That works, brilliant, thanks! 🙏 So one more question: what does "stx" abbreviate? ☺️

creating a fresh @leanprover project: 4 GB for “def hello := "world"” 🤗

@freekwiedijk @leanprover They don't, this syntax is pretty much hard-coded. But you can choose a non-reserved name for the syntax, like `syntax (name := thmStx) ... @[macro thmStx]`

@derKha @leanprover This works very smoothly! But I now have one more request… ☺️ For fun, I tried keeping my file free of unicode. But now I have this line `@[macro «thm»]`. Do these `« »` brackets have ascii equivalents? I hope so? And, if not, can I add those without having to use unicode? 😁

@ShriramKMurthi @freekwiedijk @leanprover Absolutely, the current code generator is not optimized for size at all. It would also be great to have more modularity than shipping the entire compiler as source and modules and static and dynamic libraries to every user.

@derKha @freekwiedijk @leanprover Still, not so… lean? (-:

@freekwiedijk @leanprover Haha, I haven't heard that suggestion before. But Mathlib.Tactic.Basic implements a `lemma` synonym whose implementation you could copy

@derKha @leanprover And now that I’m talking to you: suppose I would like to be able to write “thm” instead of “theorem” (too long! 😊), just as a keyword synonym. Is there some magical Lean prelude that I can prefix to my file that will give me that?

Unreasonably excited about some upcoming additions to our Rust Book Experiment!!

@JDHamkins @EscardoMartin Check this out:

A bunch of us have been working on translating mathematics to a form a computer can understand (specifically #leanprover). Here's an early version: @XenaProject @derKha (video at youtu.be/_NMquXd0Qos)

@roeschinc @glaebhoerl @derKha @d_christiansen honestly Lean 4 is probably the only FP language that can touch my love of Haskell even though it’s completely different. considering i’ve used haskell for 15yrs+, worked on GHC for 6 years, including being the release manager — it’s truly something special. hats off to everyone!

someone on the Haskell subreddit asked for a review of Lean 4, so I wrote out some stuff based on my initial impressions early last year, with some basic examples. you might enjoy it if you're a functional programmer: old.reddit.com/r/haskell/comm…

ICYMI: Sebastian Ullrich (KIT) at #RacketCon Metaprograms and Proofs: Macros in Lean 4 youtu.be/n1Pd0GeHsAY @derKha @leanprover #leanprover #metaprogramming #macros

i truly believe that i will usher in a new era of peace and prosperity when i get every single post on hthis fucking website deleted by 2022

@hillelogram I think that would have ended with more than just one bird on fire

Shoulda just made the petting zoos