Andrey Bakuta dra1n

What is dhall?

let makeUser = \(user : Text) ->
      let home       = "/home/${user}"
 let privateKey = "${home}/.ssh/id_ed25519"

UI should be an afterthought
Write code that allows to sepearate business logic frow UI.
Write code that allows to inject any hard-to-test, too-verbose, want-this-mocked stuff logic.

It has special place for handling business logic, called middleware.
Popular middleware have a mechanism for context injection. If you are writing your own custom middleware, then you probably should think about adding this too.

UI should be an afterthought

Better testability via the fewer levels of indirection. To trigger business processes you call methods or invoke functions, not clicking buttons.
Better testability via DI in some form. In React code jest.mock is the only "unobtrusive" way to replace dependencies.
Discoverability. Business logic isn't scattered across a bunch of components.
Reusability. Sometimes you want to reuse only business logic and not the UI tied to it.
Readability. It is easier to reason about business logic.

Visual documentation
- Discoverability (Easier to find existing components. Potentially works for designers too. As a result, we are saving time because we are not doing the same thing again and again)
- Regression (Breaking design or API changes will be reflected)
- Describes component API (And edge cases)
- Hints to intended usage
Faster design delivery (than having component embedded into the page)

	const range = (start: number, end: number) =>
	Array.from({ length: end - start + 1 }, (v, k) => k + start);

	/* Monad */
	const ret = <T>(x: T): T[] => [x];
	const bind = <T>(xs: T[], f: (v: T) => T[]): T[] => xs.map(f).flat();
	const fail = <T>(_: T): T[] => [];

	/* Knight problem */
	type KnightPos = [number, number];

	// user module
	const receive = (_user, sender, message) => {
	console.log(`${new Date().toLocaleString()} [${sender}]: ${message}`);
	};

	// chat room module
	const createChatRoom = (users = []) => ({
	users
	});

	const execute = (command, ...args) => command(...args);

	function PlaceOrderCommand(order, id) {
	return orders => {
	const result = [...orders, { id }];
	console.log(`You have successfully ordered ${order} (${id})`);

	return { success: true, result };
	};
	}

	(ns number-puzzles.imbaru
	(:refer-clojure :exclude [==]) ;; Prevent ns conflict
	(:require [clojure.core.logic :refer :all]))

	(def answers (run* [q]
	(fresh [r1 r2 r3 r4
	r5 r6 r7 r8
	r9 r10 r11 r12
	r13 r14 r15 r16]