Sergey Vinokurov sergv

GADTs That Can Be Newtypes and How to Roll 'Em

I think many people know about Data.Some.Newtype⁠—⁠it uses quite a cute (and cursed) trick to encode a simple existential wrapper as a newtype, hence avoiding an unwanted indirection in the runtime representation.

But there's more to data than existentials⁠—⁠so how far do these tricks go? The answer is: surprisingly far! Let's see what other GADTs we can slim down.

Preliminaries

Think twice before abandoning X11. Wayland breaks everything!

Wayland breaks everything! It is binary incompatible, provides no clear transition path with 1:1 replacements for everything in X11, and is even philosophically incompatible with X11. Hence, if you are interested in existing applications to "just work" without the need for adjustments, then you may be better off avoiding Wayland.

Wayland solves no issues I have but breaks almost everything I need. Even the most basic, most simple things (like xkill) - in this case with no obvious replacement. And usually it stays broken, because the Wayland folks mostly seem to care about Automotive, Gnome, maybe KDE - and alienating everyone else (e.g., people using just an X11 window manager or something like GNUstep) in the process.

Feature comparison

Programming as Theory Building

Peter Naur, 1985

(copied from http://alistair.cockburn.us/ASD+book+extract%3A+%22Naur,+Ehn,+Musashi%22)

Introduction

The present discussion is a contribution to the understanding of what programming is. It suggests that programming properly should be regarded as an activity by which the programmers form or achieve a certain kind of insight, a theory, of the matters at hand. This suggestion is in contrast to what appears to be a more common notion, that programming should be regarded as a production of a program and certain other texts.

	import android.annotation.TargetApi;
	import android.content.Context;
	import android.content.res.Configuration;
	import android.graphics.Bitmap;
	import android.graphics.Canvas;
	import android.graphics.Matrix;
	import android.graphics.PointF;
	import android.graphics.RectF;
	import android.graphics.drawable.Drawable;
	import android.net.Uri;

	import Data.Bits
	import Data.Word
	import System.Random

	mtN = 624
	mtM = 397

	data MersenneTwister = MersenneTwister [Word32] Int
	deriving Show