Aaron Franks af

Phantom types in ReasonML

Introduction

"A phantom type is a parametrised type whose parameters do not all appear on the right-hand side of its definition..." Haskell Wiki, PhantomType

The following write-up is intended as an introduction into using phantom types in ReasonML.

Taking a look at the above definition from the Haskell wiki, it states that phantom types are parametrised types where not all parameters appear on the right-hand side. Let's try to see if we can implement a similar example as in said wiki.

Making Impossible States Impossible in ReasonML

Introduction

If you have already seen Richard Feldman's talk entitled "Making Impossible States Impossible" or have read "Designing with types: Making illegal states unrepresentable" then you can skip the explanations and just head straight to the Reason examples.

This post is intended to display how to model your Reason Application to prevent creating impossible states. The benefits of being able to design a feature in this way include avoiding having to deal with complex test scenarios regarding defined business rules and a clear documentation of what is possible just by looking at the type definition. Long story short, let's see how this all works by implementing an example.

Requirements

What I Wish I'd Known About Equity Before Joining A Unicorn

Disclaimer: This piece is written anonymously. The names of a few particular companies are mentioned, but as common examples only.

This is a short write-up on things that I wish I'd known and considered before joining a private company (aka startup, aka unicorn in some cases). I'm not trying to make the case that you should never join a private company, but the power imbalance between founder and employee is extreme, and that potential candidates would

Who pays when startup employees keep their equity?

JD Maturen, 2016/07/05, San Francisco, CA

As has been much discussed, stock options as used today are not a practical or reliable way of compensating employees of fast growing startups. With an often high strike price, a large tax burden on execution due to AMT, and a 90 day execution window after leaving the company many share options are left unexecuted.

There have been a variety of proposed modifications to how equity is distributed to address these issues for individual employees. However, there hasn't been much discussion of how these modifications will change overall ownership dynamics of startups. In this post we'll dive into the situation as it stands today where there is very near 100% equity loss when employees leave companies pre-exit and then we'll look at what would happen if there were instead a 0% loss rate.

What we'll see is that employees gain nearly 3-fold, while both founders and investors – particularly early investors – get dilute


	module StringContext =
	Context.MakePair({
	type t = string;
	let defaultValue = "Awesome";
	});

	let component = ReasonReact.statelessComponent("Tree");

	let make = _children => {

	" when triggering this command, vim will grab your path and line location and pass it along
	map <Leader>el :call RemoteSendCommand(TestLineCommand(expand("%:p"), line(".")))<CR>

	" because I'm mostly writing Elixir and making heavy use of the REPL while writing my tests,
	" I made a specific command to user with Mix, the Elixir task utility
	" But I'm sure you could get this to work with vim-test or something like that
	function! TestLineCommand(path, line_number)
	let cmd = join(["mix test --only", " line:", a:line_number, " ", a:path], "")
	return cmd
	endfunction

	/*
	remote-data ported to ReasonML

	See also https://github.com/krisajenkins/remotedata
	Tools for fetching data from remote sources (incl. HTTP).
	*/

	type remoteData 'e 'a
	= NotAsked
	\| Loading

	var str = 'class ಠ_ಠ extends Array {constructor(j = "a", ...c) {const q = (({u: e}) => {return { [`s${c}`]: Symbol(j) };})({});super(j, q, ...c);}}' +
	'new Promise((f) => {const a = function* (){return "\u{20BB7}".match(/./u)[0].length === 2 \|\| true;};for (let vre of a()) {' +
	'const [uw, as, he, re] = [new Set(), new WeakSet(), new Map(), new WeakMap()];break;}f(new Proxy({}, {get: (han, h) => h in han ? han[h] ' +
	': "42".repeat(0o10)}));}).then(bi => new ಠ_ಠ(bi.rd));';

	try {
	eval(str);
	} catch(e) {
	alert('Your browser does not support ES6!')
	}

	local usbWatcher = nil

	-- This is our usbWatcher function
	-- lock when yubikey is removed
	function usbDeviceCallback(data)
	-- this line will let you know the name of each usb device you connect, useful for the string match below
	hs.notify.show("USB", "You just connected", data["productName"])
	-- Replace "Yubikey" with the name of the usb device you want to use.
	if string.match(data["productName"], "Yubikey") then
	if (data["eventType"] == "added") then

	-- show running queries (pre 9.2)
	SELECT procpid, age(query_start, clock_timestamp()), usename, current_query
	FROM pg_stat_activity
	WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
	ORDER BY query_start desc;

	-- show running queries (9.2)
	SELECT pid, age(query_start, clock_timestamp()), usename, query
	FROM pg_stat_activity
	WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'