Nov 29, 2013 · Nov 29, 2013 · Nov 29, 2013 · Nov 29, 2013 · Nov 29, 2013
diff --git a/components/expression_language/extending.rst b/components/expression_language/extending.rst
 .. index::
    single: Extending; ExpressionLanguage

 Extending the ExpressionLanguage
 ================================

 The ExpressionLanguage can be extended by adding custom functions. For
 instance, in the framework, the security has custom functions to check the
 user's role.

 .. note::

    If you want to learn how to use functions in an expression, read
    ":ref:`component-expression-functions`".

 Register Functions
 ------------------

 Functions will be registered on the current ``ExpressionLanguage`` instance.
 That means the functions can be used in any expression executed by that
 instance.

 To register a function, use
 :method:`Symfony\\Component\\ExpressionLanguage\\ExpressionLanguage::register``.
 This method has 3 arguments:

 * **name** - The name of the function in an expression;
 * **compiler** - A function executed when compiling an expression using the
  function;
 * **evaluator** - A function executed when the expression is evaluated.

 .. code-block:: php

    use Symfony\Component\ExpressionLanguage\ExpressionLanguage;

    $language = new ExpressionLanguage();
    $language->register('lowercase', function ($str) {
        if (!is_string($str)) {
            return $str;
        }

        return sprintf('strtolower(%s)', $str);
    }, function ($str) {
        if (!is_string($str)) {
            return $str;
        }

        return strtolower($str);
    });

    echo $language->evaluate('lowercase("HELLO")');

 This will print ``hello``.

 Creating a new ExpressionLanguage class
 ---------------------------------------

 When you use the ``ExpressionLanguage`` class in your library, it's recommend
 to create a new ``ExpressionLanguage`` class and register the functions there.
 The class will execute ``registerFunctions`` to register the default
 functions, you can override this to also add your own functions::

    namespace Acme\AwesomeLib\ExpressionLanguage;

    use Symfony\Component\ExpressionLanguage\ExpressionLanguage as BaseExpressionLanguage;

    class ExpressionLanguage extends BaseExpressionLanguage
    {
        protected function registerFunctions()
        {
            parent::registerFunctions(); // do not forget to also register core functions

            $this->register('lowercase', function ($str) {
                if (!is_string($str)) {
                    return $str;
                }

                return sprintf('strtolower(%s)', $str);
            }, function ($str) {
                if (!is_string($str)) {
                    return $str;
                }

                return strtolower($str);
            });
        }
    }
diff --git a/components/expression_language/index.rst b/components/expression_language/index.rst

    introduction
    syntax
    extending
diff --git a/components/expression_language/syntax.rst b/components/expression_language/syntax.rst

 This will print ``Hi Hi Hi!``.

 .. _component-expression-functions:

 Working with Functions
 ----------------------

 You can also use registered functions in the expression by using the same
 syntax as PHP and JavaScript. The ExpressionLanguage component comes with one
 function by default: ``constant()`` Which will return the value of the PHP
 constant::

    define('DB_USER', 'root');

    echo $language->evaluate(
        'constant("DB_USER")'
    );

 This will print ``root``.

 .. tip::

    To read how to register your own function to use in an expression, see
    ":doc:`/components/expression_language/extending`".

 .. _component-expression-arrays:

 Working with Arrays

 This will print out ``42``.

 Assignment Operators
 ~~~~~~~~~~~~~~~~~~~~

 * ``=``

 Bitwise Operators
 ~~~~~~~~~~~~~~~~~


 * ``..`` (range)

 For example::

    class User
    {
        public $age;
    }

    $user = new User();
    $user->age = 34;

    $language->evaluate(
        'user.age in 18..45',
        array(
            'user' => $user,
        )
    );

 This will evaluate to ``true``, because ``user.age`` is in the range from
 ``18`` till ``45``

 Ternary Operators
 ~~~~~~~~~~~~~~~~~

diff --git a/components/map.rst.inc b/components/map.rst.inc

  * :doc:`/components/expression_language/introduction`
  * :doc:`/components/expression_language/syntax`
  * :doc:`/components/expression_language/extending`

 * **Filesystem**
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,87 @@
		.. index::
		single: Extending; ExpressionLanguage

		Extending the ExpressionLanguage
		================================

		The ExpressionLanguage can be extended by adding custom functions. For
		instance, in the framework, the security has custom functions to check the
		user's role.

		.. note::

		If you want to learn how to use functions in an expression, read
		":ref:`component-expression-functions`".

		Register Functions
		------------------

		Functions will be registered on the current ``ExpressionLanguage`` instance.
		That means the functions can be used in any expression executed by that
		instance.

		To register a function, use
		:method:`Symfony\\Component\\ExpressionLanguage\\ExpressionLanguage::register``.
		This method has 3 arguments:

		* name - The name of the function in an expression;
		* compiler - A function executed when compiling an expression using the
		function;
		* evaluator - A function executed when the expression is evaluated.

		.. code-block:: php

		use Symfony\Component\ExpressionLanguage\ExpressionLanguage;

		$language = new ExpressionLanguage();
		$language->register('lowercase', function ($str) {
		if (!is_string($str)) {
		return $str;
		}

		return sprintf('strtolower(%s)', $str);
		}, function ($str) {
		if (!is_string($str)) {
		return $str;
		}

		return strtolower($str);
		});

		echo $language->evaluate('lowercase("HELLO")');

		This will print ``hello``.

		Creating a new ExpressionLanguage class
		---------------------------------------

		When you use the ``ExpressionLanguage`` class in your library, it's recommend
		to create a new ``ExpressionLanguage`` class and register the functions there.
		The class will execute ``registerFunctions`` to register the default
		functions, you can override this to also add your own functions::

		namespace Acme\AwesomeLib\ExpressionLanguage;

		use Symfony\Component\ExpressionLanguage\ExpressionLanguage as BaseExpressionLanguage;

		class ExpressionLanguage extends BaseExpressionLanguage
		{
		protected function registerFunctions()
		{
		parent::registerFunctions(); // do not forget to also register core functions

		$this->register('lowercase', function ($str) {
		if (!is_string($str)) {
		return $str;
		}

		return sprintf('strtolower(%s)', $str);
		}, function ($str) {
		if (!is_string($str)) {
		return $str;
		}

		return strtolower($str);
		});
		}
		}
Original file line number	Diff line number	Diff line change
Expand Up		@@ -6,3 +6,4 @@ Expression Language

		introduction
		syntax
		extending
Original file line number	Diff line number	Diff line change
Expand Up		@@ -81,6 +81,29 @@ #"687662cdc0af9b27fb2a4aea073382249fed7b5dd61682c6a3ae4f29c7961bd4">
		This will print ``Hi Hi Hi!``.

		.. _component-expression-functions:

		Working with Functions
		----------------------

		You can also use registered functions in the expression by using the same
		syntax as PHP and JavaScript. The ExpressionLanguage component comes with one
		function by default: ``constant()`` Which will return the value of the PHP
		constant::

		define('DB_USER', 'root');

		echo $language->evaluate(
		'constant("DB_USER")'
		);

		This will print ``root``.

		.. tip::

		To read how to register your own function to use in an expression, see
		":doc:`/components/expression_language/extending`".

		.. _component-expression-arrays:

		Working with Arrays
Expand DownExpand Up		@@ -128,11 +151,6 @@ For example::

		This will print out ``42``.

		Assignment Operators
		~~~~~~~~~~~~~~~~~~~~

		* ``=``

		Bitwise Operators
		~~~~~~~~~~~~~~~~~

Expand DownExpand Up		@@ -249,6 +267,26 @@ Numeric Operators

		* ``..`` (range)

		For example::

		class User
		{
		public $age;
		}

		$user = new User();
		$user->age = 34;

		$language->evaluate(
		'user.age in 18..45',
		array(
		'user' => $user,
		)
		);

		This will evaluate to ``true``, because ``user.age`` is in the range from
		``18`` till ``45``

		Ternary Operators
		~~~~~~~~~~~~~~~~~

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -61,6 +61,7 @@

		* :doc:`/components/expression_language/introduction`
		* :doc:`/components/expression_language/syntax`
		* :doc:`/components/expression_language/extending`

		* Filesystem

Expand Down