fn.php
Code (php)
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<?php
namespace Wj\fn;
function operator($operator)
{
if ('^' === $operator) {
return function ($a, $b) { return pow($a, $b); };
}
return eval('return function ($a, $b) { return $a '.$operator.' $b; };');
}
function curry()
{
$boundArgs = func_get_args();
if (is_callable(current($boundArgs))) {
// left curry
$func = current($boundArgs);
array_shift($boundArgs);
return function () use ($func, $boundArgs) {
$callArgs = func_get_args();
return call_user_func_array($func, array_merge($callArgs, $boundArgs));
};
}
if (is_callable(end($boundArgs))) {
// right curry
$func = end($boundArgs);
array_pop($boundArgs);
return function () use ($func, $boundArgs) {
$callArgs = func_get_args();
return call_user_func_array($func, array_merge($boundArgs, $callArgs));
};
}
}
class SuccessiveIterator implements \Iterator
{
private $acc;
private $initialValue;
private $step;
private $end;
public function __construct($initialValue = 0, $step = 1, $end = false)
{
$this->initialValue = $initialValue;
$this->step = $step;
$this->end = $end;
}
public function current()
{
return $this->acc;
}
public function next()
{
$this->acc += $this->step;
}
public function prev()
{
$this->acc -= $this->step;
}
public function valid()
{
if (false !== $this->end) {
return ($this->step > 0 ? $this->acc <= $this->end : $this->acc >= $this->end);
}
return true;
}
public function rewind()
{
$this->acc = $this->initialValue;
}
public function key()
{
return null;
}
}
abstract class CallableIterator extends \IteratorIterator
{
protected $callback;
public function __construct(\Traversable $iterator, $callback)
{
if (!is_callable($callback)) {
throw new \InvalidArgumentException('CallbackIterator::__construct() expects second argument to be callable.');
}
$this->callback = $callback;
parent::__construct($iterator);
}
}
class CallbackIterator extends CallableIterator
{
public function current()
{
$f = $this->callback;
return $f(parent::current());
}
}
class TakeIterator extends CallableIterator
{
public function valid()
{
if (!parent::valid()) {
return false;
}
$f = $this->callback;
return $f($this->current());
}
}
function range($start, $end)
{
switch (func_num_args()) {
case 2:
return new SuccessiveIterator($start, 1, $end);
case 3:
$args = func_get_args();
return new SuccessiveIterator($start, $end - $start, $args[2]);
default:
throw new \InvalidArgumentException(sprintf('Range expected two or three arguments, %s given.', func_num_args()));
}
}
function map($callback, \Traversable $subject)
{
return new CallbackIterator($subject, $callback);
}
function reduce($callback, \Traversable $subject, $acc = null)
{
foreach ($subject as $s) {
$acc = $callback($acc, $s);
}
return $acc;
}
function filter($callback, \Traversable $subject)
{
return new \CallbackFilterIterator($subject, $callback);
}
function takeWhile($callback, \Traversable $subject)
{
return new TakeIterator($subject, $callback);
}
function to_iterator(array $subject)
{
return new \ArrayIterator($subject);
}
function to_array(\Traversable $subject)
{
$array = array();
foreach ($subject as $s) {
$array[] = $s;
}
return $array;
}
// som van de eerste 5 even getallen.
// 2 + 4 + 6 + 8 + 10 = 30
// reduce(operator('+'), map(curry(operator('*'), 2), range(1,5)));
// eerste tien tientallen
// to_array(map(curry(operator('*'), 10), range(1, 10)));
// aantal even getallen kleiner of gelijk aan 100
// count(to_array(takeWhile(curry(operator('<='), 100), map(curry(operator('*'), 2), range(1, INF)))));
// aantal kwadraten onder de 100
// count(to_array(takeWhile(curry(operator('<='), 100), map(curry(operator('^'), 2), range(1, INF)))));
namespace Wj\fn;
function operator($operator)
{
if ('^' === $operator) {
return function ($a, $b) { return pow($a, $b); };
}
return eval('return function ($a, $b) { return $a '.$operator.' $b; };');
}
function curry()
{
$boundArgs = func_get_args();
if (is_callable(current($boundArgs))) {
// left curry
$func = current($boundArgs);
array_shift($boundArgs);
return function () use ($func, $boundArgs) {
$callArgs = func_get_args();
return call_user_func_array($func, array_merge($callArgs, $boundArgs));
};
}
if (is_callable(end($boundArgs))) {
// right curry
$func = end($boundArgs);
array_pop($boundArgs);
return function () use ($func, $boundArgs) {
$callArgs = func_get_args();
return call_user_func_array($func, array_merge($boundArgs, $callArgs));
};
}
}
class SuccessiveIterator implements \Iterator
{
private $acc;
private $initialValue;
private $step;
private $end;
public function __construct($initialValue = 0, $step = 1, $end = false)
{
$this->initialValue = $initialValue;
$this->step = $step;
$this->end = $end;
}
public function current()
{
return $this->acc;
}
public function next()
{
$this->acc += $this->step;
}
public function prev()
{
$this->acc -= $this->step;
}
public function valid()
{
if (false !== $this->end) {
return ($this->step > 0 ? $this->acc <= $this->end : $this->acc >= $this->end);
}
return true;
}
public function rewind()
{
$this->acc = $this->initialValue;
}
public function key()
{
return null;
}
}
abstract class CallableIterator extends \IteratorIterator
{
protected $callback;
public function __construct(\Traversable $iterator, $callback)
{
if (!is_callable($callback)) {
throw new \InvalidArgumentException('CallbackIterator::__construct() expects second argument to be callable.');
}
$this->callback = $callback;
parent::__construct($iterator);
}
}
class CallbackIterator extends CallableIterator
{
public function current()
{
$f = $this->callback;
return $f(parent::current());
}
}
class TakeIterator extends CallableIterator
{
public function valid()
{
if (!parent::valid()) {
return false;
}
$f = $this->callback;
return $f($this->current());
}
}
function range($start, $end)
{
switch (func_num_args()) {
case 2:
return new SuccessiveIterator($start, 1, $end);
case 3:
$args = func_get_args();
return new SuccessiveIterator($start, $end - $start, $args[2]);
default:
throw new \InvalidArgumentException(sprintf('Range expected two or three arguments, %s given.', func_num_args()));
}
}
function map($callback, \Traversable $subject)
{
return new CallbackIterator($subject, $callback);
}
function reduce($callback, \Traversable $subject, $acc = null)
{
foreach ($subject as $s) {
$acc = $callback($acc, $s);
}
return $acc;
}
function filter($callback, \Traversable $subject)
{
return new \CallbackFilterIterator($subject, $callback);
}
function takeWhile($callback, \Traversable $subject)
{
return new TakeIterator($subject, $callback);
}
function to_iterator(array $subject)
{
return new \ArrayIterator($subject);
}
function to_array(\Traversable $subject)
{
$array = array();
foreach ($subject as $s) {
$array[] = $s;
}
return $array;
}
// som van de eerste 5 even getallen.
// 2 + 4 + 6 + 8 + 10 = 30
// reduce(operator('+'), map(curry(operator('*'), 2), range(1,5)));
// eerste tien tientallen
// to_array(map(curry(operator('*'), 10), range(1, 10)));
// aantal even getallen kleiner of gelijk aan 100
// count(to_array(takeWhile(curry(operator('<='), 100), map(curry(operator('*'), 2), range(1, INF)))));
// aantal kwadraten onder de 100
// count(to_array(takeWhile(curry(operator('<='), 100), map(curry(operator('^'), 2), range(1, INF)))));