scturtle

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:

ANSI Escape Sequences

Standard escape codes are prefixed with Escape:

Ctrl-Key: ^[
Octal: \033
Unicode: \u001b
Hexadecimal: \x1B
Decimal: 27

I've never had great understanding of launchctl but the deprecation of the old commands with launchctl 2 (10.10) has been terrible as all resources only cover the old commands, and documentation for Apple utilities is generally disgracefully bad, with launchctl not dissembling.

Mad props to https://babodee.wordpress.com/2016/04/09/launchctl-2-0-syntax/ which contains most details

domains

Internally, launchd has several domains, but launchctl 1 would only ask for service names,

Effective Modern CMake

Getting Started

For a brief user-level introduction to CMake, watch C++ Weekly, Episode 78, Intro to CMake by Jason Turner. LLVM’s CMake Primer provides a good high-level introduction to the CMake syntax. Go read it now.

After that, watch Mathieu Ropert’s CppCon 2017 talk Using Modern CMake Patterns to Enforce a Good Modular Design (slides). It provides a thorough explanation of what modern CMake is and why it is so much better than “old school” CMake. The modular design ideas in this talk are based on the book [Large-Scale C++ Software Design](https://www.amazon.de/Large-Scale-Soft

Increase key repeat rate on macOS

Settings: System Preferences » Keyboard » Key Repeat/Delay Until Repeat

Use the commands below to increase the key repeat rate on macOS beyond the possible settings via the user interface. The changes aren't applied until you restart your computer.

Source: https://apple.stackexchange.com/a/83923

Basic unit type:

λ> replTy "()"
() :: ()

Basic functions:

The Borrow Checker

This pass has the job of enforcing memory safety. This is a subtle topic. This docs aim to explain both the practice and the theory behind the borrow checker. They start with a high-level overview of how it works, and then proceed to dive into the theoretical background. Finally, they go into detail on some of the more subtle aspects.

 # Download latest archlinux bootstrap package, see https://www.archlinux.org/download/
 wget 'ftp://ftp.nluug.nl/pub/os/Linux/distr/archlinux/iso/latest/archlinux-bootstrap-*-x86_64.tar.gz'
 # Make sure you'll have enough entropy for pacman-key later.
 apt-get install haveged
 # Install the arch bootstrap image in a tmpfs.
 mount -t tmpfs none /mnt
 cd /mnt
 tar xvf ~/archlinux-bootstrap-*-x86_64.tar.gz --strip-components=1

	{-# OPTIONS_GHC -Wall -fno-warn-incomplete-patterns #-}
	{-# LANGUAGE DataKinds #-}
	{-# LANGUAGE PolyKinds #-}
	{-# LANGUAGE KindSignatures #-}
	{-# LANGUAGE GADTs #-}
	{-# LANGUAGE TypeFamilies #-}
	{-# LANGUAGE TypeOperators #-}
	{-# LANGUAGE NPlusKPatterns #-}
	module Main where

	import Control.Monad.State.Lazy
	import Control.Monad.Error
	import Control.Monad.Identity
	import Control.Applicative

	import Data.Char

	-- Begin parser
	type Parser a = StateT String (ErrorT String Identity) a