acutmore

Immutability is Equality's support act [hackmd]

When considering the design of the Record & Tuple proposal a core driver in much of the design stems primarily from equality rather than immutability.

Categorizing equality

There are many ways to think about equality but one way to divide up the design space is two dimensions.

	pure	impure

acutmore

/** @param promises {Array<Promise<unknown>>} */
export async function * onSettled(promises) {
    let wake;
    let wait = new Promise(_ => wake = _);
    let pending = promises.length;
    const queue = [];

    for (const p of promises) {
        Promise.allSettled([p]).then(([result]) => {
            queue.push(result);

acutmore

// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// this approach fails to handle cycles
// next attempt: https://gist.github.com/acutmore/d1aaaff27c898fdd26b2e15de5c2f7c6

const {Tuple, FakeSymbol} = ToyTupleLib();
const Box = BoxLib(FakeSymbol);
const TupleWeakMap = TupleWeakMapLib(Tuple, FakeSymbol, v => FakeSymbol.isFakeSymbol(v));

const wm = new TupleWeakMap();

acutmore

---

• Erasable
• Gradual
• Structural
• Generic
• Inferable

acutmore

// @ts-check
const childProcess = require('child_process');
const path = require('path');
const TTL_MS = 5000;

/**
 * @description Start a connection to tsserver
 * @param {{debug?: boolean}} options
 * @example
    const chat = tsserverAPI.start();

acutmore

Web Framework Render Functions

A look at the different render functions created by different web-frameworks, for the same website.

Website is very minimal:

• A large rectangle than can recursively render 9 more rectangles inside it
• Can navigate around the rectangles (Cells) using the keyboard

Vanilla.js demo https://gistpreview.github.io/?154fa3d4a17c3e124eb9ea0e7b69ae1d/z_vanilla.html

acutmore

function updateFocus(elm) {
  const focusedClass = 'focused';
  const currentlyFocused = document.querySelector('.' + focusedClass);
  if (currentlyFocused != null) {
    currentlyFocused.classList.remove(focusedClass);
  }
  if (elm) {
    elm.classList.add(focusedClass);
  }
}

acutmore

A compile-time 4-Bit Virtual Machine implemented in TypeScript's type system. Capable of running a sample 'FizzBuzz' program.

Syntax emits zero JavaScript.

type RESULT = VM<
  [
    ["push", N_1],         // 1
    ["push", False],       // 2
 ["peek", _], // 3

acutmore

// ASHEMBLER
type B = 1 | 0;
type BITS_4 = [B,B,B,B];

// note: 'assert' interfaces function as unit tests
interface assert {
  true: 1;
  false: 0;
}

acutmore

import {resolve, Service, ResolvedService} from './resolve';

describe('resolve', () => {
    it('resolves a single service graph', () => {
        const input: Service[] = [
            {
                name: 'a',
                requires: []
            }
        ];