Will Ware wware

Can you put LaTeX-style math in a Github Gist? Yes you can.

Use https://www.codecogs.com/eqnedit.php to edit your math. Use the little menu at the bottom to select "HTML (Edit)", and copy the stuff into your Gist. Here is a fairly meaningless example.

$\int^{2\pi}_0 \frac{x^2}{\sqrt{1-{v^2/c^2}}} dx = 11$

Clicking on this will allow your reader to review and edit the source.

Instrument for 2018

Before spending time and money building a lot of electronics, let's prototype the thing in Javascript.

Hmm. Maybe a better idea would be to make up a board that accepts a Teensy 3.6, and provides audio hardware, and a bunch of pushbuttons and a few other controllers. Then you can develop code on a real Teensy with representative hardware support. When you go to the real instrument you're only changing the form factor, and maybe the number of buttons or switching to touch-sensitive or whatever.

Prior art - the Tooba, 2015

Non-blocking

The System.lang.Runtime.exec() method is non-blocking, so you call it and it spawns a background process.

Unfortunately the java.lang.Process thingy in Java 8 has no way to get a PID, so you need a cheesy hack to find it.

Messing with Ansible and Docker

Nobody can remember how to use Docker, it is far too confusing. So here are some hints.

sudo docker build -t simple_flask:dockerfile .
sudo docker run -p 5000:5000 simple_flask:dockerfile python hello.py

My actual intention is to learn Ansible. But in order to run Ansible you need Docker, unless you happen to have a rackful of machines at your disposal which I do not.

Feature toggle decorator

This is a feature toggle scheme for the system I maintain at my job. The goal is to be able to easily toggle functions that have been recently pushed to production, so if things go bad, we have an easy mitigation plan.

Create a database table with three columns, Key (string), Value (boolean), LastChanged (timestamp). The purpose of the LastChanged column is just for record keeping to decide when a feature is deemed trustworthy. The several for a given key string present the history of switching the feature on and off,

	v1 = [0, 2, -1];
	v2 = [1, 3, 3];
	y = [v2[0] - v1[0], v2[1] - v1[1], v2[2] - v1[2]];
	translate(v1)
	rotate(-acos(y[2] / norm(y)), cross(y, [0, 0, 1]))
	cylinder(h=norm(y), d=0.1);

	#!/usr/bin/env python
	# https://en.wikipedia.org/wiki/Isomorphic_keyboard
	# any hexagonal layout is defined by two offsets (the value of the third is forced by the first two)

	import sys

	many = [20 * [None] for _ in range(20)]

	def display():
	width = 4

	#!/bin/bash

	wait_all() {
	# As soon as one of the background processes creates the EPIC_FAIL file,
	# kill all background processes, rm EPIC_FAIL, and stop looping.
	while [ $(jobs \| grep -v Done \| wc -l) -ne 0 ]; do
	sleep 1
	if [ -f EPIC_FAIL ]; then
	rm -f EPIC_FAIL
	echo OUCH

	#!/usr/bin/env python

	import argparse
	import logging
	import os
	import sys
	import pprint
	from textwrap import dedent

	HERE = os.path.dirname(__file__)

	#!/usr/bin/env python

	import logging
	from flask import Flask

	from twisted.internet import ssl, reactor
	from twisted.web.wsgi import WSGIResource
	from twisted.web.server import Site
	from twisted.python.threadpool import ThreadPool
	from twisted.application import service