Ayaz Hafiz (Aug 15 2024 at 02:48): Ayaz Hafiz (Aug 15 2024 at 02:48):Alright I have a present for you all
I built a compiler that properly compiles lambda sets. The key insight is making sure to solve the type of lambda captures, transitively
See this example that solves a long-standing lambda set bug and enables effect interpreters in my compiler
The issue it solves is https://github.com/roc-lang/roc/issues/5464
If you want to study the source code, which is quite small but many passes, it is here https://github.com/ayazhafiz/cor/tree/base/experiments/lss
This is a proper monomorphizing compiler. I don't emit machine code or anything like that but the low-level IR pass is first-order and is trivial to compile to C or asm
Sam Mohr (Aug 15 2024 at 02:51):Holy shit
Luke Boswell (Aug 15 2024 at 02:51):Sam Mohr said:
Holy shit
Well said
Sam Mohr (Aug 15 2024 at 02:51):Wait, so we don't need type erasure, do we??
Sam Mohr (Aug 15 2024 at 02:55):If that's the case, I'd be happy to help with the translation of this work to the Roc compiler! Super exciting
Luke Boswell (Aug 15 2024 at 03:12):Likewise, if there is anything we need on the platform side, like updating Brendan's POC I'm happy to help too.
Richard Feldman (Aug 15 2024 at 12:22):omg omg omg
Richard Feldman (Aug 15 2024 at 12:23):THIS IS THE BEST NEWS!!!!!!!
Richard Feldman (Aug 15 2024 at 12:24)::star_struck::star_struck::star_struck::star_struck::star_struck::star_struck::star_struck::star_struck::star_struck::star_struck::star_struck:
Brendan Hansknecht (Aug 15 2024 at 21:59):I can't wait for when this lands in Roc! Will unlock so much stuff!!!
Brendan Hansknecht (Aug 15 2024 at 21:59):I can't wait for true async effect interpreters
Brendan Hansknecht (Aug 15 2024 at 22:00):Also should unblocks some random complex code like my sqlite improvements for basic-webserver and the better version of encode and decode.
Luke Boswell (Aug 15 2024 at 23:12):There's a nice long list of really awesome things this should enable. I'm so excited to hear this news. Thank you Ayaz for sharing :grinning_face_with_smiling_eyes:
Ayaz Hafiz (Aug 18 2024 at 03:23):I've also partially implemented type erasure, as needed for Map2 - Map2 example here
Richard Feldman (Sep 20 2024 at 22:33):quick note - I'm gonna take on the implementation of this!
Brendan Hansknecht (Sep 21 2024 at 01:25):Infinitely excited :laughing:
Agus Zubiaga (Sep 21 2024 at 02:56):Let’s gooo
Ayaz Hafiz (Dec 29 2024 at 00:24):I was going to implement part of this in the Roc codebase the past couple days but I figured it would probably be a better use of my time to describe the implementation in significant detail, so that it can be discussed and hopefully easy for anyone to contribute to.
Here's a doc with the compilation process in significant detail - it's the same code as I shared before, but this time well-annotated (PR, doc). Please let comments/critiques/let me know where I'm using confusing language/what could be more clear/etc, I will address them.
I'll get to the remaining detailed sections on function lifting, function solving, and function specialization tonight and in the next few days.
Of note, I still think that switching to have all recursive types required to be nominal would make much of this simpler and more efficient in the long term. See https://github.com/roc-lang/rfcs/blob/ayaz/compile-with-lambda-sets/0102-compiling-lambda-sets.md
Last updated: Jul 26 2025 at 12:14 UTC