Paolo Giarrusso (Sep 17 2020 at 20:42): Paolo Giarrusso (Sep 17 2020 at 20:42):There are _general_ questions with DSLs and embedded DSLs, including whether users are disciplined enough.
Paolo Giarrusso (Sep 17 2020 at 20:43):If you don’t trust your users, maybe you should prevent them from doing even pure computations. That’s basically the Go argument, but I totally buy that :-).
Karl Palmskog (Sep 17 2020 at 20:43):at least make them pay commensurately for pure computation, like on blockchains, heh
Paolo Giarrusso (Sep 17 2020 at 20:43):Except I usually don’t choose Go-like systems.
Paolo Giarrusso (Sep 17 2020 at 20:44):mind you, I’m also happy to rant about SBT, like any Scala user
Karl Palmskog (Sep 17 2020 at 20:44):I used Scala a while, SBT seemed like the hackiest hack ever
Paolo Giarrusso (Sep 17 2020 at 20:45):I don’t think _that_ is the problem.
Paolo Giarrusso (Sep 17 2020 at 20:45):Using higher-kinded types in a build system might be closer to it.
Paolo Giarrusso (Sep 17 2020 at 20:45):Not even Haskellers do that in _their_ build systems ;-)
Karl Palmskog (Sep 17 2020 at 20:46):did they even have a metaphor (mental abstract model) for SBT at all? If so, I never noticed
Paolo Giarrusso (Sep 17 2020 at 20:47):Yes. Took just a few years to document it.
Paolo Giarrusso (Sep 17 2020 at 20:47):And after a few more years, one developer managed to understand it and explain why it had a couple of concepts in excess.
Karl Palmskog (Sep 17 2020 at 20:48):this sounds familiar for the Scala community (Akka comes to mind, although in reverse)
Karl Palmskog (Sep 17 2020 at 20:49):there [in Akka], they started with a clean concept, and then made it unrecognizable
Paolo Giarrusso (Sep 17 2020 at 20:49):no no, in SBT the author started with a clean concept.
Paolo Giarrusso (Sep 17 2020 at 20:49):it’s even enforced by types and whatnot.
Karl Palmskog (Sep 17 2020 at 20:50):what was it, and why can't anyone tell what it is?
Paolo Giarrusso (Sep 17 2020 at 20:50):I suspect they had one of the first HList implementations in production? Actually a KList — so a list of type constructors.
Paolo Giarrusso (Sep 17 2020 at 20:50):Basically, it was written by a type astronaut who left very little documentation.
Paolo Giarrusso (Sep 17 2020 at 20:51):so the _usage_ was hacky, just cargo-cult what works.
Paolo Giarrusso (Sep 17 2020 at 20:52):but nowadays the model is documented, it’s just not immediate.
Paolo Giarrusso (Sep 17 2020 at 20:53):sorry, that was a slight understatement, and my “exercise for the reader” moment
Karl Palmskog (Sep 17 2020 at 20:53):"type astronaut" :laughter_tears:
Paolo Giarrusso (Sep 17 2020 at 20:54):oh, that’s a term of art, and not mine
Karl Palmskog (Sep 17 2020 at 20:54):the equivalent of the pattern-happy Java programmer?
Paolo Giarrusso (Sep 17 2020 at 20:54):this is an analysis: https://www.lihaoyi.com/post/SowhatswrongwithSBT.html
Paolo Giarrusso (Sep 17 2020 at 20:55):it’s more like somebody who in Coq picks Vector, or rather intrinsically-typed syntax
Paolo Giarrusso (Sep 17 2020 at 20:55):even when it’s overcomplicated for the task at hand
Paolo Giarrusso (Sep 17 2020 at 20:55):requiring multiple PhD to be able to contribute
Paolo Giarrusso (Sep 17 2020 at 20:56):for higher marks, they might want to paint themselves into a corner by being unable to wield the tools properly
Paolo Giarrusso (Sep 17 2020 at 20:56):(I recall a prominent Haskeller complaining about Haskell programmers bringing too many commercial Haskell projects to failure this way)
Paolo Giarrusso (Sep 17 2020 at 20:58):OTOH, (since we’re hopelessly OT) in this channel I’d rather be suspicious about OCaml’s lack of control for side effects — I am not sure, but it does seem like Coq suffers terribly from it
Karl Palmskog (Sep 17 2020 at 20:58):ah, the problem in many industry-oriented PL communities (in my opinion) is that they really have close to zero incentives to write anything but plain old how-do-I-use-this documentation
Karl Palmskog (Sep 17 2020 at 21:00):feel free to break this out from parent topic by changing the topic at some well-chosen point
Paolo Giarrusso (Sep 17 2020 at 21:01):(wouldn’t know where at this point, and I’m on the app which doesn’t seem to let me)
Karl Palmskog (Sep 17 2020 at 21:01):OK I will do it at what will probably be the wrong point in hindsight
Paolo Giarrusso (Sep 17 2020 at 21:01):re docs, that’s somewhat true but SBT seems a special case... all we know is the author disappeared from the Internet (maybe because of the reactions)
Karl Palmskog (Sep 17 2020 at 21:03):hmm, isn't the community a bit embarrassed that they adopted a tool they had no idea how it worked?
Paolo Giarrusso (Sep 17 2020 at 21:03):however, some of the SBT ideas are really nice, and I think it is in some sense declarative — a task can depend on another one by using its result — and that’s done automatically by defining an appropriate monad. And your build files just describe a build to be later executed :-)
Paolo Giarrusso (Sep 17 2020 at 21:04):hm, I’m not sure they should be embarrassed.
Karl Palmskog (Sep 17 2020 at 21:05):sigh, I would send them the original Mokhov et al. paper and tell them to get back on where SBT fits
Paolo Giarrusso (Sep 17 2020 at 21:05):SBT was the first tool to support fine-grained incremental builds...
Paolo Giarrusso (Sep 17 2020 at 21:05):for Scala, that is
Karl Palmskog (Sep 17 2020 at 21:05):by fine-grained, do you mean edits at the method level?
Paolo Giarrusso (Sep 17 2020 at 21:06):nowadays yes
Paolo Giarrusso (Sep 17 2020 at 21:06):back then it wasn’t so good I think, but it was still better than the alternatives
Karl Palmskog (Sep 17 2020 at 21:06):and how do they deal with dynamic dependencies and reflection and so on?
Paolo Giarrusso (Sep 17 2020 at 21:07):in any case: like for dune, it builds Scala projects faster than alternatives, so people did the right thing
Paolo Giarrusso (Sep 17 2020 at 21:08):re dynamic deps, I’d have to look at your link on Selective to understand what you mean.
Paolo Giarrusso (Sep 17 2020 at 21:08):on reflection, do you mean Java reflection?
Karl Palmskog (Sep 17 2020 at 21:08):it's not really related to that. You have to do your change impact analysis accurately to get correct fine-grained builds
Paolo Giarrusso (Sep 17 2020 at 21:09):ah, the dependencies of a Scala file are completely static in that sense
Paolo Giarrusso (Sep 17 2020 at 21:09):if a class loads another class, you cannot predict the runtime types, that’s true
Karl Palmskog (Sep 17 2020 at 21:09):dynamic class loading/modification and so on?
Paolo Giarrusso (Sep 17 2020 at 21:10):not a problem in the compilation model
Paolo Giarrusso (Sep 17 2020 at 21:10):the _output_ of compilation only depends on the source and the dependencies.
Paolo Giarrusso (Sep 17 2020 at 21:10):there’s a strict stage separation between compile-time and runtime.
Paolo Giarrusso (Sep 17 2020 at 21:11):well. Except for (compile-time) macros, and those _are_ hackier in Scala 2.
Paolo Giarrusso (Sep 17 2020 at 21:12):those indeed are a problem because they’re basically compiler plugins, up to some sealing of ML-modules, which you can anyway bypass fairly easily with Obj.magic and friends.
Karl Palmskog (Sep 17 2020 at 21:32):my number one mistake when reading tech writing by non-academics: scrolling directly to the conclusion and assuming it actually sums up what the document is about (re: https://www.lihaoyi.com/post/SowhatswrongwithSBT.html)
Last updated: Apr 19 2024 at 00:02 UTC