| 21 Jul 2025 |
 maralorn | I mean, is it a different ghc version than when you added those flags? | 10:20:28 |
 magic_rb | i think i found it | 10:21:36 |
| magic_rb | there was a problem between the keyboard and my chair | 10:21:50 |
| magic_rb | the monkey forgot to use a variable he declared | 10:21:57 |
 Alex | In reply to @magic_rb:matrix.redalder.org
im benchmarking a thing i wrote and im making a nix package out of a cabal file using cabal2nix, however if i change the source cabal file and remove -fllvm, -O2, or -fexpose-all-unfoldings the performance measurements dont seem to change even though im positive they should. Is nixpkgs overwriting my flags somehow? If you're using a profiling build, beware of automatic cost centres (IIRC enabled by default in cabal). | 10:37:54 |
| magic_rb | In reply to @alex:tunstall.xyz
If you're using a profiling build, beware of automatic cost centres (IIRC enabled by default in cabal). Nope, i know about those | 10:49:29 |
| 22 Jul 2025 |
| maralorn | Does anyone here grok/has used the useIntermediates stuff? I have one question: Can it reuse the intermediates of a previous build even when that build had other dependency hashes on the nix side? The argument was that cabal-install does not always have to recompile your project when you modify your nix shell. And the reusing is probably happening based on some cabal level hashing? | 15:02:25 |
 sterni (he/him) | Well development shell is out anyways since that's Setup.hs which cabal-install won't be able to reuse in any shape or form I think | 18:57:16 |
| maralorn | Are you sure? Maybe the components are similar enough? I mean they have been compiled with the same ghc. Isn’t it basically a dir with .hie and object files in both cases? | 20:55:26 |
| 24 Jul 2025 |
|  Keeton Brewster joined the room. | 00:12:02 |
| Keeton Brewster | Hi everyone, is there a Haskell specific Nix beginner guide out there? | 00:14:32 |
 keypusher | I think it's a bit fragmented depending on your needs / approach as can be seen in this thread https://www.reddit.com/r/haskell/comments/1cqfboq/latest_guidance_on_using_haskell_with_nix/ . Some years ago my searches often ended up here https://haskell4nix.readthedocs.io/ | 00:45:35 |
| keypusher | I would suggest you start wo using these evolved approaches and try to have as few layers on top of "vanilla"/"flakes" nix | 01:09:48 |
| Keeton Brewster | Thank you! | 01:51:31 |
| Keeton Brewster | There seems to be a thousand ways to do it which is confusing for a newbie | 01:56:06 |
|  bglgwyng joined the room. | 05:41:12 |
| bglgwyng | Hello! I'm trying to build a nixpkgs.haskellPackages from an arbitrary stackage snapshot. I just found regenerate-hackage-packages.sh in nixpkgs and also hackage2nix in cabal2nix. Is hackage2nix enough for my purpose? I don't fully understand how two tools differ. | 05:54:08 |
| maralorn | @keetonbrewster:matrix.org haskell4nix.readthedocs.io is outdated. It's uptodate version is the nixpkgs manual Haskell section. | 06:07:02 |
