07c09-2.php

介绍PHP5的给类型函数应用

<?php
// Define a class that will overload a method definition
class Money {
    // Define an addition function that handles many different variations:
    public function __call($name, $args) {
        // If the function name was 'format' then:
        if (($name == 'format') && (count($args) == 1)) {
            // If the first argument is a string:
            if (is_string($args[0])) {
                // Call the string version of the formatter:
                return $this->_format_string($args[0]);
            } elseif (is_numeric($args[0])) {
                // If numeric, call the number version
                return $this->_format_number($args[0]);
            } elseif (is_array($args[0])) {
                // Use the array version now.
                return $this->_format_array($args[0]);
            }
        }
        
        // In any other case, we didn't have a proper method call, exit
        trigger_error('Invalid Method Access', E_USER_ERROR);
    }

    // Define the private/internal function for formatting a number as money
    private function _format_number($number) {
        // First round it to 2 decimal places:
        $number = round($number, 2);
        
        // Now output it, with formatting:
        return '$' . number_format($number, 2);
    }
    
    // Define the private/internal function for formatting a string as money
    private function _format_string($str) {
        // Clean up the string by removing all chars that are not digits:
        $str = preg_replace('/[^0-9.]/', '', $str);
        
        // Ensure that only one decimal separator exists:
        $str = preg_replace('/\.([^.]*)(?=\.)/', '$1', $str);

        // Now that it is clean, call format number on it:
        return $this->_format_number($str);
    }

    // Define the private/internal function for formatting an array as money
    private function _format_array($arr) {
        // Loop through the entire array
        $new = array();
        foreach ($arr as $a) {
            // Depending on whether this is a string, call the appropiate 
            // function to format it, and save it in a new array:
            if (is_string($a)) {
                $new[] = $this->_format_string($a);
            } else {
                $new[] = $this->_format_number($a);
            }
        }
        
        // Now return the new array back:
        return $new;
    }    
}

// Create a new object
$my_money = new Money();

// Examine the output of calling this method in multiple ways:
// As a number: $1,234.57
echo '<p>Accessed as number: ', $my_money->format(1234.567), '</p>';
// As a string with some garbage in it: $7,561.20
echo '<p>Accessed as array: ', $my_money->format('big7,56.1.2'), '</p>';
// And as an array of these mixed values:
//   Array ( [0] => $2.22 [1] => $2,345.64 [2] => $42.00 )
echo '<p>Accessed as individual numbers: ';
print_r($my_money->format(array(2.217, '2-345.64', 42)));
echo '</p>';
?>