polytypic

A pattern for using GADTs to subset cases

Consider the following straightforward mutable queue implementation using two stacks:

type 'a adt_queue = {
  mutable head : 'a head;
  mutable tail : 'a tail;
}

neel-krishnaswami

module C : sig
  type t 
  val empty : t 
  val one : char -> t 
  val union : t -> t -> t 
  val inter : t -> t -> t 
  val top : t 
  val mem : char -> t -> bool 
  val make : (char -> bool) -> t 
  val equal : t -> t -> bool

n1zyy

Apple runs a fleet of stratum 1 NTP servers at time.apple.com. In my experience, ntpd/chronyd are very happy with them.

It looks like, instead of doing anycast, they maybe use DNS to steer you to the closest one.

time.apple.com is a CNAME for time-osx.g.aaplimg.com. Querying a handful of DNS servers, I've identified the following locations:

IP	Hostname	Location
17.253.2.125	usdal4-ntp-001.aaplimg.com.	Dallas

lancethomps

function run(input, parameters) {
  const appNames = [];
  const skipAppNames = [];
  const verbose = true;

  const scriptName = 'close_notifications_applescript';

  const CLEAR_ALL_ACTION = 'Clear All';
  const CLEAR_ALL_ACTION_TOP = 'Clear';
  const CLOSE_ACTION = 'Close';

merijn

The Cabal/Stack Disambiguation Guide

One of the most frequently asked Haskell beginner questions in recent years is:

"Stack or cabal?"

I will helpfully not answer this question. Instead I will hope to eliminate the confusion that many of the askers seem to have about the various different

nepsilon

How to use Mac KeyChain to store GitHub repos credentials?

You know the pain, you cloned a repo over HTTPS, and now Git asks you for your password each time you want to push or pull.

Chances are you already have the git credential-osxkeychain command installed. If not, just install Git with brew: brew install git.

Once installed, just tell Git to use the KeyChain to store your credentials:

git config --global credential.helper osxkeychain

Zenexer

This gist has moved to a proper git repo so people can make pull requests: https://github.com/Zenexer/internet-reference/blob/main/Mac%20Keyboard%20Symbols.md

jbgi

import static java.lang.System.*;

import java.util.function.BiFunction;
import java.util.function.Function;

// Implementation of a pseudo-GADT in Java, translating the examples from
// http://www.cs.ox.ac.uk/ralf.hinze/publications/With.pdf
// The technique presented below is, in fact, just an encoding of a normal Algebraic Data Type
// using a variation of the visitor pattern + the application of the Yoneda lemma to make it
// isomorphic to the targeted 'GADT'.