Utility functions for PHP 5.5+

util.php

<?php
/**
 * Utility functions for PHP 5.5+
 *
 * @copyright 2015 Shay Anderson <http://www.shayanderson.com>
 * @license MIT License <http://www.opensource.org/licenses/mit-license.php>
 * @link <http://www.shayanderson.com/php/php-utility-functions.htm>
 */

/**
 * Class autoloading
 *
 * @param array $autoload_paths
 * @return void
 */
function autoload(array $autoload_paths)
{
	set_include_path(get_include_path() . PATH_SEPARATOR . implode(PATH_SEPARATOR, $autoload_paths));

	function __autoload($class)
	{
		require_once str_replace('\\', DIRECTORY_SEPARATOR, $class) . '.php';
	}
}

/**
 * Decorate values
 *
 * @param string $decorator
 * @param mixed $value
 * @param mixed $_
 * @return string
 */
function decorate($decorator, $value, $_ = null)
{
	$value = array_slice(func_get_args(), 1); // rm decorator

	$udf = [];
	foreach($value as $k => $v) // find user defined functions
	{
		if(is_array($v))
		{
			$udf = array_filter($v, function($v) use(&$value, &$k) // set user defined functions
			{
				if(is_callable($v))
				{
					unset($value[$k]); // rm UDFs from values
					return true;
				}
			});
		}
	}

	$filter = function($value, &$callable, &$values = null) use(&$udf)
	{
		if(isset($udf[$callable])) // user defined function
		{
			return $udf[$callable]($value, $values);
		}
		else if(is_callable($callable)) // PHP standard built-in function
		{
			return $callable($value);
		}
		else
		{
			user_error('Failed to find filter \'' . $callable . '\'', \E_USER_WARNING);
		}

		return $value;
	};

	if(is_string($decorator) && count($value))
	{
		$pattern = '/{\$([\w]+)(?:\:([^}]+))?}/i';
		$pattern_d = '/{\$([\d]+)(?:\:([^}]+))?}/i';

		if(is_scalar($value[0])) // scalar value
		{
			$i = 0;
			// test {$[n]} params, ex: {$1}
			preg_replace_callback($pattern_d, function($m) use(&$value, &$decorator,
				&$filter, &$i)
			{
				if(isset($value[$m[1] - 1]) || array_key_exists($m[1] - 1, $value))
				{
					$decorator = str_replace($m[0], isset($m[2])
						? $filter($value[$m[1] - 1], $m[2]) : $value[$m[1] - 1],
							$decorator);
					$i++;
				}
			}, $decorator);

			if(!$i) // use {$named} (ordered) params
			{
				preg_replace_callback($pattern, function($m) use(&$value, &$decorator,
					&$filter, &$i)
				{
					if(isset($value[$i]) || array_key_exists($i, $value))
					{
						$decorator = str_replace($m[0], isset($m[2])
							? $filter($value[$i], $m[2]) : $value[$i], $decorator);
					}
					$i++;
				}, $decorator);
			}
		}
		else if(is_object($value[0])) // single object
		{
			$decorator = call_user_func_array(__FUNCTION__, [$decorator, (array)$value[0], $udf]);
		}
		else if(is_array($value[0])) // array
		{
			if(!isset($value[0][1])) // one-dimensional
			{
				$value = $value[0];

				preg_replace_callback($pattern, function($m) use(&$value, &$decorator, &$filter)
				{
					if(isset($value[$m[1]]) || array_key_exists($m[1], $value))
					{
						$decorator = str_replace($m[0], isset($m[2])
							? $filter($value[$m[1]], $m[2], $value)
							: $value[$m[1]], $decorator);
					}
				}, $decorator);
			}
			else // multidimensional
			{
				$out = '';

				foreach($value[0] as $v)
				{
					$out .= call_user_func_array(__FUNCTION__, [$decorator, $v, $udf]);
				}

				$decorator = &$out;
			}
		}
	}

	return $decorator;
}

/**
 * String/array printer for debugging
 *
 * @var mixed $v
 * @return void
 */
function pa($v = null)
{
	if(count(func_get_args()) > 1)
	{
		foreach(func_get_args() as $arg) pa($arg);
		return;
	}
	echo is_scalar($v) || $v === null ? $v . ( PHP_SAPI === 'cli' ? PHP_EOL : '<br />' )
		: ( PHP_SAPI === 'cli' ? print_r($v, true) : '<pre>' . print_r($v, true) . '</pre>' );
}