PHP Declaring constant in namespace

Question

I want to declare constants inside of a namespace. I want them not to be visible outside of it of course.

Using define() won't work because it makes constants global regardless of the namespace it's executed in (if i understood well).

So can i do :

namespace paths;

const models  = 'Models/';
const views   = 'Views/';
const classes = 'Classes/';

And somewhere else :

require_once(paths\models.'user.php'); // works
require_once(models.'user.php');       // fails

Also if i do :

namespace ns;
namespace subNs;

Am i in ns\subNs or in subNs ?

PS: i know doing require_once('Models/user.php'); would be simpler, but that's just an example.

dev-null-dweller · Accepted Answer · 2012-11-28 00:12:17Z

4

Ad 1. Yes you can. can be checked by running your example script; (but you may have to use \paths\constant or use paths; first)

Ad 2. subNs Can be checked by echo __NAMESPACE__;

answered Nov 28, 2012 at 0:12

dev-null-dweller

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2 Comments

dev-null-dweller Over a year ago

Just be aware that if you move your namespaces into separate files across directory tree, you may have to include it manually, autoload does not trigger for namespaced constants/function/

Virus721 Over a year ago

You mean that i will have to require the file where i declared the namespace contents before i can use name\myConstant ?

Kevin Florida · Accepted Answer · 2012-11-28 00:23:42Z

1

You can't do what you want.

the only way you can use the constant "models" in the require function if it is defined as you stated you do not want to do.

Why don't you write a class to do this?

<?php
class PATHS {

    public $models = null;
    public $views = null;
    public $classes = null;

    public function __construct($namespace) {

         switch ($namespace) {
            case 'path1' :
                $this->models = 'my_custom_path/models';
                $this->$views = 'my_custom_path/views';
                $this->classes = 'my_custom_path/classes';
             break;
             case 'path2' :
                $this->models = 'my_custom_path/models';
                $this->$views = 'my_custom_path/views';
                $this->classes = 'my_custom_path/classes';
             break;
             default :
                $this->models = 'my_custom_path/models';
                $this->$views = 'my_custom_path/views';
                $this->classes = 'my_custom_path/classes';
             break;
         }

    }

}

$paths =new PATHS('my_namespace');

echo $paths->models;
echo $paths->views;
echo $paths->classes;

?>

I don't fully understand what your end-goal is, but I think I get the gist of it, and a similar class turned into an object should accomplish what you want.

You can simply include that class in your framework where necessary.

Hope that helps

edited Nov 28, 2012 at 0:23

answered Nov 28, 2012 at 0:14

Kevin Florida

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2 Comments

Virus721 Over a year ago

I have folders containing classes and nammed : Models, Views, and Classes. Before using PHP 5.3 i simply defined constants using define() and had things like MODELS_DIR, VIEWS_DIR, CLASSES_DIR, etc... i wanted to use namespaces and constants to make that cleaner and eventually shorter to write in some cases.

Kevin Florida Over a year ago

Yep, dev-null-dweller has the right answer. I didn't understand your question at first. But my post might help someone else, so I'll leave it there.

b01 · Accepted Answer · 2014-08-09 14:21:13Z

1

You CAN use define to declare namespace constants, like so:

<?php namespace paths;
// Preferred way in a file that does not declare the namespace:
define('paths\\models', 'Models/');
define('paths\\views', 'Views/');
define('paths\\classes', 'Classes/');

// Preferred way in file with the namespace declared:
const models  = 'Models/';
const views   = 'Views/';
const classes = 'Classes/';
?>

Coming in PHP 5.6, you will be able to auto load constants via the "use" keyword, see here: http://php.net/manual/en/migration56.new-features.php

answered Aug 9, 2014 at 14:21

b01

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