07c09-1.php

介绍PHP5的给类型函数应用

<?php
// Define a class that will overload a method definition
class Overloaded_Math {
    // Define an addition function that handles many different variations:
    public function __call($name, $args) {
        // If the function name was 'add' then:
        if ($name == 'add') {
            // If the first argument is a string:
            if (is_string($args[0])) {
                // Concatenate all the strings together:
                return implode('', $args);
            } elseif ((count($args) == 1) && is_array($args[0])) {
                // Ok we have exactly one argument, and it's an array
                // so sum up the values of the array:
                return array_sum($args[0]);
            } elseif ((count($args) > 1) && is_numeric($args[0])) {
                // If there are more than 1 arguments, and the
                // first one at least is numeric, then add them all:
                return array_sum($args);
            }
        }
        
        // In any other case, we didn't have a proper method call, exit
        trigger_error('Invalid Method Access', E_USER_ERROR);
    }
}

// Create a new object
$mobj = new Overloaded_Math();

// Examine the output of calling this method in multiple ways:
// As strings: 'RedWhiteBlue'
echo '<p>Accessed as strings: ', $mobj->add('Red', 'White', 'Blue'), '</p>';
// As an array of numbers: 16
echo '<p>Accessed as array: ', $mobj->add(array(7, 6, 3)), '</p>';
// And as a bunch of numbers: 42
echo '<p>Accessed as individual numbers: ', 
    $mobj->add(37.83, 3.17, 1), '</p>';
?>