<?php
class Water
{
public $color = 'clear';
public $temp = 'cold';
}
class Pipeline
{
/**
* @var array The parameters to pass through
*/
protected $parameters = [];
/**
* @var \Closure[] The list of pipes that the parameters will fall through
* Pipe should match function($parameter..., \Closure $next) {}
*/
protected $pipes = [];
/**
* @type \Closure The "then" closure, it will receive the parameters you pipe through
*/
protected $thenClosure;
/**
* @inheritdoc
*/
public function send(...$parameters) : PipelineMap
{
$this->parameters = $parameters;
return $this;
}
/**
* @inheritdoc
*/
public function through($pipes) : PipelineMap
{
$this->pipes = is_array($pipes) ? $pipes : func_get_args();
return $this;
}
/**
* @inheritdoc
*/
public function then(callable $then) : PipelineMap
{
$this->thenClosure = $then;
return $this;
}
/**
* @inheritdoc
*/
public function execute()
{
$pipes = array_reverse($this->pipes);
/** @type \Closure $linked_closure */
$linked_closure = array_reduce($pipes, $this->getIterator(), $this->getInitial($this->thenClosure));
return $linked_closure(...$this->parameters);
}
/**
* Get the iterator closure, this wraps every item in the list and injects the
* @return \Closure
*/
protected function getIterator() : \Closure
{
return function ($next, $pipe) {
return function (...$parameters) use ($next, $pipe) {
$parameters[] = $next;
return $pipe(...$parameters);
};
};
}
/**
* The initial closure
* @return \Closure
*/
protected function getInitial(\Closure $then) : \Closure
{
return function(...$parameters) use ($then) {
return $then(...$parameters);
};
}
}
// Lets make some pipes
$color_water_blue_pipe = function (Water $water, callable $next_pipe) {
$water->color = 'blue';
// We colored it, now we're done. Send it to the next pipe and return the result!
return $next_pipe($water);
};
$heat_water_pipe = function (Water $water, callable $next_pipe) {
$water->temp = 'hot';
// We heated it, send it to the next pipe!
return $next_pipe($water);
};
// Make some water
$water = $factory->getWater();
// Send it through our pipes
$piped_water = (new \Buttress\Pipeline\Pipeline())
->send($water)
->through([ $color_water_blue_pipe, $heat_water_pipe ])
->then(function($water) {
return $water;
});
echo "The water is {$piped_water->color} and {$piped_water->temp}!";