Vmap in Haskell

[g0xA52A2A]

http://blog.ezyang.com/2020/01/vmap-in-haskell/

[fmakunbound]

> We're going to need a few language extensions, so let's get this out of the way first: {-# LANGUAGE RankNTypes, GADTs, MultiParamTypeClasses, KindSignatures, TypeApplications, FunctionalDependencies, FlexibleContexts, FlexibleInstances, UndecidableInstances, IncoherentInstances #-}

Dang, how do you know to use that?

[lalaithion → fmakunbound]

There's a bunch here that are sort of "We need X so we also must enable Y and Z". For instance, FunctionalDependencies requires MultiParamTypeClasses and IncoherentInstances requires UndecideableInstances and FlexibleInstances.

[kryptiskt → fmakunbound]

Quite often the error messages will tell you what extension to enable to use that construct.

[whateveracct → fmakunbound]

The same way you know to import a library? It's just importable language features, mostly in existence to not force trade-offs or backwards incompatibility on everyone willy nilly.

I thought it was weird when I moved from Scala to Haskell but now I am unimpeded by it thanks to practice.

[hopia → fmakunbound]

This feels absurd indeed. Like half of the GHC extensions introduce only some trivial syntactical convenience whereas the other half each introduce practically a whole new language.

This list aligns more with the latter description.

[tome → hopia]

All of those extensions match the description of "things one thought that Haskell should have been able to do anyway" (some more tenuously than others, granted).

[dllthomas → tome]

IncoherentInstances?

[gowld → hopia]

I wish C++ features had that level of transparency and control.

[choeger → fmakunbound]

This is Haskell's equivalent of node.js' dependency hell.

[mcbuilder → choeger]

Hardly, Cabal Hell is the Haskell equivalent. You can enable all these extensions module wide by putting them in your project file. This is more a case of having to learn a plethora of advanced Haskell extensions, and when to use them.

[whateveracct → mcbuilder]

And cabal is vastly improved nowadays anyways. I'm not familiar with npm, but does it have anything like cabal's Nix-style builds?

[gowld → choeger]

No, it's equivalent to python's "from __future__ import foo"

[skainswoo]

vmap is by far my favorite feature in JAX. Very cool to see that you can get the same thing straight out of haskell.