kybernetikos kybernetikos

Transducers Primer

function reducerFn(output, value) {
	// reducer functions know how to build a structure when repeatedly given
	// that structure and values (think of it as 'builder')
	return output
}
function reduceFn(collection, reducerFn, output) {

Keybase proof

I hereby claim:

I am kybernetikos on github.
I am kybernetikos (https://keybase.io/kybernetikos) on keybase.
I have a public key whose fingerprint is 4D54 659A DBC4 D807 220C 03E4 7DD3 2D18 A8D8 2630

To claim this, I am signing this object:

	class Op {
	constructor(symbol, precedence, leftAssociate, apply) {
	Object.assign(this, {symbol, precedence, leftAssociate, apply})
	}
	process(stack) {
	if (this.apply === null) return
	const args = []
	for (let i = 0; i < this.apply.length; i++) {
	const arg = stack.pop()
	if (arg === undefined) {

	const min = (a,b) => (a < b) ? a : b // this works on big ints too, unlike Math.min
	const err = message => {throw new Error(message)} // useful if you want to throw an error in an expression
	const castToNumber = bigInt => (BigInt(bigInt) <= Number.MAX_SAFE_INTEGER) ? Number(bigInt) : err(`Number too big: ${bigInt} > MAX_SAFE_INTEGER`)
	const prefixTo = (array, length) => (array.length >= length) ? array : [...Array(length - array.length).fill(0), ...array]
	const factorial = (() => {
	const lookupTableSize = 20
	let lastVal = 1n
	const lookUp = Array.from({length: lookupTableSize}, (_,i) => lastVal = i === 0 ? lastVal : BigInt(i) * lastVal)

	return function factorial(n) {

	<html>
	<head>
	<style>
	body {
	background-color: turquoise;
	}

	#age {
	color: white;
	font-size: xxx-large;

	<html>
	<head>
	<style>
	body {
	background-color: turquoise;
	}

	#age {
	color: white;
	font-size: xxx-large;

	<html>
	<head>
	<title>React</title>
	<script type="application/javascript" crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
	<script type="application/javascript" crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
	</head>
	<body>
	<div id="root"></div>

	<script type="application/javascript">

	const fetch = require('node-fetch');

	const lotteries = {
	lotto: {
	balls: [
	{number: 6, from:1, to: 59}
	]
	},
	euromillions: {
	balls: [

	const line = '"" "a b" "a b c" "a \\" marvellous" \'we like\'a"b a""b abab abb "hi"';

	const gre = /\s(?:(?:"((?:\\"\|[^"]))")\|(?:'((?:\\'\|[^'])*)')\|([^\s]+))/g;
	function split(str) {
	const result = [];
	str.replace(gre, (part, dquoteMatch, squoteMatch, wsMatch, offset, fullString) => {
	result.push(dquoteMatch !== undefined ? dquoteMatch : squoteMatch !== undefined ? squoteMatch : wsMatch)
	});
	return result;
	}

	// You should probably use Vorpal.js instead of this.
	// usage demo down at the bottom of the file...

	const Repl = require('repl');
	const util = require('util');
	const fs = require('fs');
	const path = require('path');

	// Don't be a repli-can't, be a...
	class Replican {