pipe_class.php

<?php

define('PIPE_VALUE', '__pipe-' . uniqid());

class Pipe implements ArrayAccess, Iterator, Serializable
{
	public $value;
	private $position = 0;
	
	public function __construct($value)
	{
		$this->value = $value;
	}
	
	public function __call($method, $args)
	{				
		if (function_exists($method)) {
			foreach ($args as $key => $arg) {
				if ($arg === PIPE_VALUE) {
					$args[$key] = $this->value;
				}
			}
			
			$this->value = $method(...$args);
			return $this;
		}
		
		trigger_error("Function '$method' doesn't exist", E_USER_ERROR);
	}
	
	public function __get($name)
	{
		return $this->value;
	}
	
	public function __toString()
	{
		return $this->value;
	}
	
	public function pipe($value)
	{
		if (is_callable($value) and $value instanceof \Closure) {
			$this->value = $value($this->value);
		}
		
		return $this;
	}
	
	public function offsetSet($offset, $value) {
		if (is_null($offset)) {
			$this->value[] = $value;
		} else {
			$this->value[$offset] = $value;
		}
	}
	
	public function offsetExists($offset) {
		return isset($this->value[$offset]);
	}
	
	public function offsetUnset($offset) {
		unset($this->value[$offset]);
	}
	
	public function offsetGet($offset) {
		return isset($this->value[$offset]) ? $this->value[$offset] : null;
	}
	
	public function rewind() {
		$this->position = 0;
	}
	
	public function current() {
		return $this->value[$this->position];
	}
	
	public function key() {
		return $this->position;
	}
	
	public function next() {
		++$this->position;
	}
	
	public function valid() {
		return isset($this->value[$this->position]);
	}
	
	public function serialize() {
        return serialize($this->value);
    }
	
    public function unserialize($value) {
        $this->value = unserialize($value);
    }
}

pipe_function.php

if (! function_exists('pipe')) {
    /**
     * Run functions consecutively by piping through the result of one
     * into the next.
     *
     * @param mixed  $value    A value
     *
     * @return object
     */
    function pipe($value)
    {
        return new Pipe($value);
    }
}

Example usage:

$subdomain = pipe('https://blog.sebastiaanluca.com/')
    -> parse_url(PIPE_VALUE, PHP_URL_HOST)
    -> explode('.', PIPE_VALUE)
	-> reset(PIPE_VALUE);

echo $subdomain; // 'blog'