edmundsmith

Method for Emulating Higher-Kinded Types in Rust

Intro

I've been fiddling about with an idea lately, looking at how higher-kinded types can be represented in such a way that we can reason with them in Rust here and now, without having to wait a couple years for what would be a significant change to the language and compiler.

There have been multiple discussions on introducing higher-ranked polymorphism into Rust, using Haskell-style Higher-Kinded Types (HKTs) or Scala-looking Generalised Associated Types (GATs). The benefit of higher-ranked polymorphism is to allow higher-level, richer abstractions and pattern expression than just the rank-1 polymorphism we have today.

As an example, currently we can express this type:

hallettj

/* @flow */

// Helper function for matching against an ADT.
export function match<A,B>(matcher: A): (match: (matcher: A) => B) => B {
  return match => match(matcher)
}

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

whiter4bbit

import com.twitter.scalding._

class DijkstraJob(args: Args) extends Job(args) {
   val iteration = args.getOrElse("iteration", "0").toInt

   Tsv(args("input"), ('node, 'dist, 'adjacent))
     .read
     .flatMap(('node, 'dist, 'adjacent) -> ('node, 'dist, 'adjacent)) { p: (String, Int, String) =>
        val (node, distance, adjacent) = p
        (node, distance, adjacent) +: adjacent.split(":").map { part: String =>

dnagir

# RSpec 2.0 syntax Cheet Sheet by http://ApproachE.com

# defining spec within a module will automatically pick Player::MovieList as a 'subject' (see below)
module Player
	describe MovieList, "with optional description" do
		  
	  it "is pending example, so that you can write ones quickly"
	  
	  it "is already working example that we want to suspend from failing temporarily" do
		pending("working on another feature that temporarily breaks this one")