Helsinki Haskell Users Group's first book club had its conclusion meeting today with Sockets and Pipes coming to its very end. It has been a ride, one with plenty of scheduling difficulties, but I think we only fell like a month and a half from the original planned schedule and actually had a member retention rate of 100% (of members who were there in the beginning, sadly we could not quite make it 133%)!
To talk a bit about the book as a whole, I do feel like I understand Monad Transformers a lot better now though I'll still need to reread the sections introducing them I am sure. ReaderT especially was something I could see was colossally handy, but given it was in the second to last chapter we were already quite deep with trying to understand everything else so the true utility of it remains somewhat hazy despite the quality of the chapter itself which felt higher than those surrounding it. The habit of reading RFCs and attempting to match the spec in the types one writes is also one I should include in my general workflow, though that is probably a no-brainer for most. It just wasn't a thing in my previous work, so bear with me while I call it a novel concept!
I'm still working on my personal project, but getting nix-build working seems difficult. I'll just have to bring it up in the next main group Office Hours meetup I suppose, lest I never get this show on the road!
I've got a specific type that uses a #bound approach but I'd like to write some general folds (using e.g. algebra families) instead of duplicating the "traversal" code.
I might have done the categorical approach (functor categories instead of algebra families) before, but that has limitations and I think I lost the code.
Only very few breakages from Flora's #Haskell dependencies with GHC 9.10.1-alpha3. We may be able to adopt it as soon as HLS supports it (and a nice dose of "allow-newer" in cabal.project configuration)
New blog post by my colleague Finley on "Choreographing a dance with the GHC specializer (Part 1)". This is in addition to our #Haskell#Unfolder episode on the same topic tomorrow, 2024-04-16, at 1830 UTC on YouTube.
I expect the docker image would contain a GHC that stack would find and use; I am using the matching resolver for the tag (e.g.: 22.17). :blobfoxhappy:
Having to deal with type conflicts at runtime is exhausting to me. Writing non-trivial JS at work is a slog. But, I'd say #purescript is almost as much fun as #ghc#haskell and might be better-specified!
pseq combinator is used for sequencing; informally, it eval-
uates its first argument to weak-head normal form, and then eval-
uates its second argument, returning the value of its second argu-
ment. Consider this definition of parMap:
parMap f [] = []
parMap f (x:xs) = y ‘par‘ (ys ‘pseq‘ y:ys)
where y = f x
ys = parMap f xs
The intention here is to spark the evaluation of f x, and then
evaluate parMap f xs, before returning the new list y:ys. The
programmer is hoping to express an ordering of the evaluation: first
spark y, then evaluate ys.
The obvious question is this: why not use #Haskell’s built-in seq
operator instead of pseq? The only guarantee made by seq is that
it is strict in both arguments; that is, seq a ⊥ = ⊥ and seq ⊥
a = ⊥. But this semantic property makes no operational guaran-
tee about order of evaluation. An implementation could impose this
operational guarantee on seq, but that turns out to limit the optimi-
sations that can be applied when the programmer only cares about
the semantic behaviour. Instead, we provide both pseq and seq
(with and without an order-of-evaluation guarantee), to allow the
programmer to say what she wants while leaving the compiler with
as much scope for optimisation as possible. https://simonmar.github.io/bib/papers/multicore-ghc.pdf
I remember recently reading a new paper elaborating a novel presentation of graph algebras. But I can't for the life of me remember the title or the author.
The central idea was axiomatizing vertices as pairs of sets of all incoming and outgoing edges.
It also had example code in Haskell.
Does anybody have an idea of the title? I'd be very thankful for suggestions.
Finding Success (and Failure) in Haskell by Type Classes is on sale on Leanpub! Its suggested price is $35.00; get it for $12.50 with this coupon: https://leanpub.com/sh/4sG8LBPo#Haskell
@simon_brooke Hey buddy, checked out #Scheme/#Scsh yesterday, super intriguing stuff. Actually, I've been digging into #Lisp and its dialects lately. Got curious about why there are so many dialects, you know?
Recently dabbled in #Clojure, which got me looking at Lisp in a new light. Unlike #Haskell, which is awesome for sure, #Lisp has been out of academia and in the market for quite a while... found it pretty cool.