copperwall

#lang racket

;; From SICP 2.3.4

;; Leaf defintions
(define (make-leaf symbol weight)
  (list 'leaf symbol weight))
(define (leaf? object)
  (eq? (car object) 'leaf))
(define (leaf-symbol x) (cadr x))

copperwall

<?php

function simpleGenerator() {
  yield 1;
  yield 2;
}

foreach(simpleGenerator() as $val) {
  echo "$val\n";
}

copperwall

<?php

// User Generator
function getGuideAuthors(int $guideid): Iterator {
  // Guide::getUserids could be a generator too!
  foreach (Guide::getUserids($guideid) as $userid) {
    // Yield full ORM object.
    yield User::get($userid);
  }
}

copperwall

<?php

function range(int $start, int $end, int step = 1): Iterator {
  while ($start < $end) {
     yield $start;
     $start += $step;
  }
}

function infinite() {

copperwall

<?php

function lazy_map(callable $f, Iterator $list): Iterator {
   foreach ($list as $item)
      yield $f($item);
}

function lazy_filter(callable $f, Iterator $list): Iterator {
   foreach ($list as $item)
      if ($f($item))

copperwall

<?php

declare(strict_types = 1);

/**
 * Like array_map() but over an iterable, and it returns a new iterable with
 * mapping instead of a mapped array. The callable should take two arguments:
 * a value to map and its key in the stream.
 */
function iterator_map(callable $cb, iterable $itr): iterable {

copperwall

<?php

describe(strict_types = 1);

/**
 * Like array_filter() but over an iterable, and it returns a new iterable with
 * filtering instead of a filtered array. The callable, if non-null, should
 * take arguments like iterator_map(). When the callable is null, null values
 * will be filtered out (NOT falsey values, just x === null).
 */

copperwall

<?php

declare(strict_types = 1);

/**
 * Like array_reduce() but over an iterable, and it returns a single value as
 * the result of calling $cb over the contents of iterable $itr.
 *
 * If $initial is not null, $initial is set to the value of the first element
 * of the iterable, and $cb is called with the first element as the carry value

copperwall

<?php

describe(strict_types = 1);

/**
 * Example code for consuming data from a Store API (called Storeify) and chaining generators
 * together to filter, map, and eventually reduce all Order data into a
 * daily revenue total.
 */

copperwall

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

function getPlayerStats(battletag, region, platform) {
  battletag = battletag.replace('#', '-');
  const url = `https://playoverwatch.com/${region}/career/${platform}/${battletag}`;
  return fetch(url).then(response => response.text())
            .then(doc => {
              const $ = cheerio.load(doc);