note 86074 added to language.oop5.typehinting

TYPE-HINTING and VISIBILITY

Type-hinting is just one more small piece of PHP that protects our objects when visibility cannot.

<?php

class Point {
  public $x, $y;

  public function __construct($xVal = 0, $yVal = 0) {
    $this->x = $xVal;
    $this->y = $yVal;
  }
}

class Polyline {
  protected $points = array();

  public function addPoint(Point $p) {  // the line we're interested in...
    $this->points[] = $p;
  }
}

$point1 = new Point(15, 12);
$polyline = new Polyline();
$polyline->addPoint($point1);
$polyline->addPoint(new Point(55, 22));
$polyline->addPoint(new Point(33, 31));

$polyline->addPoint(new stdClass());    // PHP will throw an error for us!  

?>

Since our Polyline::addPoint() function has to be public, any outside code can try to pass anything. But, when type-hinting is declared, PHP throws an error when phoney data tries to sneak by.
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Server IP: 69.147.83.197
Probable Submitter: 67.150.1.108
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Manual Page -- http://www.php.net/manual/en/language.oop5.typehinting.php
Edit        -- https://master.php.net/note/edit/86074
Del: integrated  -- https://master.php.net/note/delete/86074/integrated
Del: useless     -- https://master.php.net/note/delete/86074/useless
Del: bad code    -- https://master.php.net/note/delete/86074/bad+code
Del: spam        -- https://master.php.net/note/delete/86074/spam
Del: non-english -- https://master.php.net/note/delete/86074/non-english
Del: in docs     -- https://master.php.net/note/delete/86074/in+docs
Del: other reasons-- https://master.php.net/note/delete/86074
Reject      -- https://master.php.net/note/reject/86074
Search      -- https://master.php.net/manage/user-notes.php