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Rich Already Answered That!

A list of commonly asked questions, design decisions, reasons why Clojure is the way it is as they were answered directly by Rich (even when from many years ago, those answers are pretty much valid today!). Feel free to point friends and colleagues here next time they ask (again). Answers are pasted verbatim (I've made small adjustments for readibility, but never changed a sentence) from mailing lists, articles, chats. The link points back at them.

Index:

• Why no pattern matching?
• Why no tail call optimization?
• Why you don't accept pull requests?

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const { log } = console;

/*
* Aritmética: equal, max, min, negative, positive, reverseSign, opositeSigns
* swap, def, undef, plus, minus, sum
*/

const equal = function( x, y ) {
  return ( x === y );
};

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const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args)))

// Usage : compose functions right to left
// compose(minus8, add10, multiply10)(4) === 42
//
// The resulting function can accept as many arguments as the first function does
// compose(add2, multiply)(4, 10) === 42

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/*

Hoje iremos MUDAR a vida da pessoa que não te responde no whatsappp... 
Que tal enviar mensagens pra ela até obter uma resposta?! 
Sensacional não acha?! Mas, somos devs, correto?! Então vamos automatizar esse paranauê!

Para utilizar:
- Abra o web.whatsapp.com;
- Selecione a conversa que você quer;
- Abra o console e cole o código que está no gist;

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const crypto = require('../../helpers/crypto')
const Errors = require('../../errors/sistem/pt-br')
const Validate = require('../../helpers/validate')


const authenticate = (User, Validate, Business, Errors) => (req, res, next) => {
  
  const exclude = ['password', 
    'created_at', 
    'updated_at', 

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const def =  ( x ) => typeof x !== 'undefined'
const identityFn =  ( x ) => x
const compose =  ( f, g ) => ( x ) => f( g( x ) )
const fold =  ( fn, acc, [ x, ...xs ] ) =>
  def( x ) && fold( fn, fn( acc, x ), xs ) || acc

const addOne =  ( x ) =>  x + 1
const timesTwo =  ( x ) =>  x * 2
const addThree =  ( x ) =>  x + 3

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const sucessor = x => x + 1;
const predecessor = x => x - 1;

// 1. P(a, 0) = a
// 2. P(a,S(b)) = S(P(a, b))
const adicaoPeano = ( a, b ) => 
  ( a === 0 )
    ? b 
    : adicaoPeano( predecessor( a ), sucessor( b ) );

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const memoize = ( fn ) => {
  const cache = {}

  return function mfn () {
    const args = [].slice.call( arguments )
    const key = JSON.stringify( args )

    return key in cache
      ? cache[ key ]
      : cache[ key ] = fn.apply( this, args )

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const fact = n => n && n * fact(n-1) || 1;
const decToBin = dec => dec && dec % 2 + 10 * decToBin(0 | dec / 2) || 0;
const iif = pr => t => f => x => pr(x) ? t(x) : f(x);
const not = fn => x => !fn(x);
const or = pra => prb => x => pra(x) || prb(x);
const isArray = x => x instanceof Array;
const isPromise = x => x instanceof Promise;
const isPlainObject = x => typeof x === 'object' && x !== null && x == '[object Object]';
const isTraversable = or(isPlainObject)(isArray);
const keys = Object.keys.bind(Object);

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// A definição de um stream se dá inicio com o uso do construtor [Stream] 
// que recebe como único parâmento uma fonte que é o gerador.
// Por meio de técnicas compositivas fluídas é que se define uma cadeia
// de composição funcional. As operações de composição são [map]
// [reduce] e [filter], versão unitária das funções sobre vetores
// e [skip] e [take] que permite saltar ou recoletar n elementos
// que passam pela cadeia de composição.
// Fonts: 
// https://sites.ualberta.ca/~jhoover/325/CourseNotes/section/Streams.htm
// http://blog.jeremyfairbank.com/javascript/functional-javascript-streams-2/