07c07-1.php

介绍PHP5的给类型函数应用

<?php
// Define an interface that will allow conversion of objects to strings
interface conversionOptions {
    public function asString();
    public function asHTML();
}

// Define a 'cat' class that implements the interface
class cat implements conversionOptions {
    // Properties of a cat
    public $name;
    public $color;

    // Constructor that requires a name
    public function __construct($namesake) {
        $this->name = $namesake;
    }

    // Implement the string function of the interface
    public function asString() {
        return "Cat - Name: {$this->name}, Color: {$this->color}";
    }
    
    // Implement the HTML function of the interface
    public function asHTML() {
        return "<ul><li>Cat</li><ul><li>Name: {$this->name}</li>
<li>Color: {$this->color}</li></ul></ul>";
    }
}

// Define class that implements the interface, for anacronym definitions
class anacronym implements conversionOptions {
    // Properties of an anacronym
    private $name;
    private $definition;

    // Constructor that requires the term entry and definition
    public function __construct($entry, $def) {
        $this->name = $entry;
        $this->definition = $def;
    }

    // Implement the string function of the interface
    public function asString() {
        return "{$this->name}: {$this->definition}";
    }
    
    // Implement the HTML function of the interface
    public function asHTML() {
        return "<dl><dt>{$this->name}</dt>
<dd>{$this->definition}</dd></dl>";
    }
}

// Instantiate a cat & give it data
$my_cat = new cat('Wiley');
$my_cat->color = 'grey tabby';

// Now return the cat as a string & echo it:
$catstring = $my_cat->asString();
echo "<pre>{$catstring}</pre>\n";

// And do the same as HTML
echo $my_cat->asHTML();

// Now construct an anacronym definition
$my_anac = new anacronym('SCA', 'Society for Creative Anacronism');

// Covert it into string form:
$anac = $my_anac->asString();
echo "<pre>{$anac}</pre>\n";

// Now output as HTML
echo $my_anac->asHTML();
?>