PHP : Sets a given variable if it is not set with the last parameter or the first non-empty value.

README.md

fallback

(PHP 5 >= 5.6)
fallback — Sets a given variable if it is not set.

Description

mixed fallback( mixed &$var [, mixed $... ] )

This function sets $var if it is not set with the last parameter or the first non-empty value.

Based on Alex Suraci's fallback() function. Updated for PHP 5.6.

Parameters

• var — The variable to return or set.
• ... — Another variable…

Return Values

Returns the value of whatever was chosen.

Examples

Example #1 fallback() example

function datetime($when = null) {
	fallback($when, time());
	$time = (is_numeric($when)) ? $when : strtotime($when) ;
	return date("Y-m-d", $time);
}

$nextWeek = time() + (7 * 24 * 60 * 60);

echo 'Now:       '. datetime() ."\n";
echo 'Next Week: '. datetime($nextWeek) ."\n";

The above example will output:

Now:       2005-03-30
Next Week: 2005-04-06

Installation

With Composer

$ composer require mcaskill/php-fallback

Without Composer

Why are you not using composer? Download Function.Fallback.php from the gist and save the file into your project path somewhere.

composer.json

{
  "name": "mcaskill/php-fallback",
  "description": "Sets a given variable if it is not set.",
  "license": "MIT",
  "authors": [
    {
      "name": "Chauncey McAskill",
      "email": "chauncey@mcaskill.ca",
      "homepage": "https://github.com/mcaskill"
    }
  ],
  "keywords": [
    "function"
  ],
  "extra": {
    "branch-alias": {
      "dev-master": "1.x-dev"
    }
  },
  "require": {
    "php": ">=5.6.0"
  },
  "autoload": {
    "files": [ "Function.Fallback.php" ]
  }
}

Function.Fallback.php

<?php

if (!function_exists('fallback')) {
	/**
	 * Sets a given variable if it is not set.
	 *
	 * The last of the arguments or the first non-empty value will be used.
	 *
	 * @link   https://github.com/vito/chyrp/ Origin of function.
	 * @param  mixed $var     The variable to return or set.
	 * @param  mixed ...$args Variable list of arguments to serve as fallbacks.
	 * @return mixed The value of whatever was chosen.
	 */
	function fallback(&$var, ...$args)
	{
		if (is_bool($var)) {
			return $var;
		}

		$set = (!isset($var) || (is_string($var) && trim($var) === '') || $var === []);

		if (count($args) > 1) {
			foreach ($args as $arg) {
				$fallback = $arg;
				if (isset($arg) && (
						!is_string($arg) || (
							is_string($arg) &&
							(trim($arg) !== '')
						)
					) &&
					($arg !== [])
				) {
					break;
				}
			}
		} else {
			$fallback = (isset($args[0]) ? $args[0] : null);
		}

		if ($set) {
			$var = $fallback;
		}

		return ($set ? $fallback : $var);
	}
}