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    User Contributed Notes 6 notes

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    116
    Anonymous
    4 years ago
    The keyword 'use' has two different applications, but the reserved word table links to here.

    It can apply to namespace constucts:

    file1:
    <?php namespace foo;
      class     Cat {
        static function     says() {echo 'meoow';}  } ?>

    file2:
    <?php namespace bar;
      class     Dog {
        static function     says() {echo 'ruff';}  } ?>

    file3:
    <?php namespace animate;
      class     Animal {
        static function     breathes() {echo 'air';}  } ?>

    file4:
    <?php namespace fub;
      include     'file1.php';
      include     'file2.php';
      include     'file3.php';
      use     foo as feline;
      use     bar as canine;
      use     animate;
      echo \    feline\Cat::says(), "<br />\n";
      echo \    canine\Dog::says(), "<br />\n";
      echo \    animate\Animal::breathes(), "<br />\n";  ?>

    Note that
    felineCat::says()
    should be
    \feline\Cat::says()
    (and similar for the others)
    but this comment form deletes the backslash (why???)

    The 'use' keyword also applies to closure constructs:

    <?php function getTotal($products_costs, $tax)
        {
                $total = 0.00;
           
                $callback =
                function (    $pricePerItem) use ($tax, &$total)
                {
                   
                        $total += $pricePerItem * ($tax + 1.0);
                };
           
                array_walk($products_costs, $callback);
            return     round($total, 2);
        }
    ?>
    up
    8
    varuninorbit at yahoo dot co dot in
    4 months ago
    here is a simple example to use namespace

    <?php

    namespace app\a{
        class     one{
           public static function     _1(){
            echo     'a one _1<br>';
           }
        }
    }

    namespace     app\b{
        class     one{
            public static function     _2(){
                echo     'b one _2<br>';
            }
        }
    }

    namespace     app{

        echo     a\one::_1();
        echo     b\one::_2();
        echo     a\two::_1();
    }

    namespace     app\a{
        class     two{
           public static function     _1(){
            echo     'a two _1<br>';
           }
        }
    }

    prints
    a one _1
    b one _2
    a two _1
    up
    7
    davidkennedy85 at gmail dot com
    1 year ago
    In addition to using namespaces and closures, the use keyword has another new meaning as of PHP 5.4 - using traits:

    <?php
    trait Hello     {
        public function     sayHello() {
            echo     'Hello ';
        }
    }

    trait World {
        public function     sayWorld() {
            echo     'World';
        }
    }

    class     MyHelloWorld {
        use     Hello, World;
        public function     sayExclamationMark() {
            echo     '!';
        }
    }

    $o = new MyHelloWorld();
    $o->sayHello();
    $o->sayWorld();
    $o->sayExclamationMark();
    ?>

    More info here: http://php.net/manual/en/language.oop5.traits.php
    up
    0
    Anonymous
    2 days ago
    Tested on PHP 7.0.5, Windows
    The line "use animate;" equals the line "use animate as animate;"
    but the "use other\animate;" equals "use other\animate as animate;"

    file1:
    <?php namespace foo;
      class     Cat {
        static function     says() {echo 'meoow';}  } ?>

    file2:
    <?php namespace bar;
      class     Dog {
        static function     says() {echo 'ruff';}  } ?>

    file3:
    <?php namespace other\animate;
      class     Animal {
        static function     breathes() {echo 'air';}  } ?>

    file4:
    <?php namespace fub;
      include     'file1.php';
      include     'file2.php';
      include     'file3.php';
      use     foo as feline;
      use     bar as canine;
      use     other\animate;       //use other\animate as animate;
          echo feline\Cat::says(), "<br />\n";
      echo     canine\Dog::says(), "<br />\n";
      echo \    animate\Animal::breathes(), "<br />\n";  ?>
    up
    -15
    Ronald W
    1 year ago
    <?php
    // multiple namespaces in a single file:

    namespace foo{
      class     Cat {
        static function     says() {echo 'meoow';}  }
    }

    namespace     bar{
      class     Dog {
        static function     says() {echo 'ruff';}  } 
      class     Cat {
        static function     says() {echo 'meowi';}  }
      class     Mouse {     //nonstatic function
            function says() {echo 'Come and get me ;)';}  }
    }

    namespace     animate{
      class     Animal {
        static function     breathes() {echo 'air';}  }
    }

    namespace{            // No Namespace: global code
          use foo as feline;
      use     bar as canine;
      use     bar\Mouse as MouseOnly;
      use     animate;
      echo     animate\Animal::breathes(), "<br />\n"; 
      echo     feline\Cat::says(), "<br />\n"; //not starting with a slash!
          echo canine\Cat::says(), "<br />\n";
      echo     canine\Dog::says(), "<br />\n";
          //any of the three following lines work:
      // $micky=new bar\Mouse();
      // $micky=new canine\Mouse();
          $micky=new test();
      echo     $micky->says();
    }
    ?>
    up
    -66
    php at lanar dot com dot au
    2 years ago
    Be warned that it is not trivial to convert a project to use namespaces. If you add the same namespace to the top of all your files, your application will break.
    All objects in the global namespace, such as ArrayObject, must have a backslash (\) prepend to them.
    If you use get_class() and instanceof, you will have to make adjustments here to.
    If you have an autoloader, you will need to change its behavior.
    It can be done, but subtle errors can creep in and are tedious to rectify.
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