array as function parameters

gistfile1.php

<?php
// Setup our options for what we want to pass
$options = array(
	'parameter1'=>'apples',
	'parameter3'=>'grapes',
	);
	
some_function($options);

function some_function($options)
{
	// Now these are the defaults
	$defaults = array(
		'parameter1'=>'oranges',
		'parameter2'=>'watermelons',
		'parameter3'=>'grapefruit',
		'parameter4'=>''
	);

	/* Now we merge the two arrays, except the $options
		array takes precedence */
	$options = array_merge($defaults, $options);
	
	/* extract() creates a variable with every key from the array
		so we can use that variable directly, this is optional */
	extract($options);
	
	// So now we can use the variables directly
	echo $parameter1; // This will echo &quot;apples&quot;
	echo $parameter2; // This will echo &quot;watermelons&quot;
	
	/* Suppose parameter4 has to be set, so we will trigger an error
		You can use throw as well if it's in a try/catch block */
	if($parameter4 == '')
	{
		trigger_error('Parameter 4 must be set to this value or that value', E_USER_WARNING);
	}

	/* Or, if you assume that the $defaults set with '' are mandatory to fill out,
		you can use this code */
	foreach($defaults as $name=>$value)
	{
		if($values == '' && $options[$name] == '' || !isset($options[$name]))
		{
			trigger_error("{$name} is blank, must have a value", E_USER_WARNING);
		}
	}
}