:github_url: hide

.. _class_Expression:

Expression
==========

**Hereda:** :ref:`RefCounted<class_RefCounted>` **<** :ref:`Object<class_Object>`

Una clase que almacena una expresión que puedes ejecutar.

.. rst-class:: classref-introduction-group

Descripción
----------------------

An expression can be made of any arithmetic operation, built-in math function call, method call of a passed instance, or built-in type construction call.

An example expression text using the built-in math functions could be ``sqrt(pow(3, 2) + pow(4, 2))``.

In the following example we use a :ref:`LineEdit<class_LineEdit>` node to write our expression and show the result.


.. tabs::

 .. code-tab:: gdscript

    var expression = Expression.new()

    func _ready():
        $LineEdit.text_submitted.connect(self._on_text_submitted)

    func _on_text_submitted(command):
        var error = expression.parse(command)
        if error != OK:
            print(expression.get_error_text())
            return
        var result = expression.execute()
        if not expression.has_execute_failed():
            $LineEdit.text = str(result)

 .. code-tab:: csharp

    private Expression _expression = new Expression();

    public override void _Ready()
    {
        GetNode<LineEdit>("LineEdit").TextSubmitted += OnTextEntered;
    }

    private void OnTextEntered(string command)
    {
        Error error = _expression.Parse(command);
        if (error != Error.Ok)
        {
            GD.Print(_expression.GetErrorText());
            return;
        }
        Variant result = _expression.Execute();
        if (!_expression.HasExecuteFailed())
        {
            GetNode<LineEdit>("LineEdit").Text = result.ToString();
        }
    }



.. rst-class:: classref-introduction-group

Tutoriales
--------------------

- :doc:`Evaluando expresiones <../tutorials/scripting/evaluating_expressions>`

.. rst-class:: classref-reftable-group

Métodos
--------------

.. table::
   :widths: auto

   +---------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`Variant<class_Variant>`         | :ref:`execute<class_Expression_method_execute>`\ (\ inputs\: :ref:`Array<class_Array>` = [], base_instance\: :ref:`Object<class_Object>` = null, show_error\: :ref:`bool<class_bool>` = true, const_calls_only\: :ref:`bool<class_bool>` = false\ ) |
   +---------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`String<class_String>`           | :ref:`get_error_text<class_Expression_method_get_error_text>`\ (\ ) |const|                                                                                                                                                                         |
   +---------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`bool<class_bool>`               | :ref:`has_execute_failed<class_Expression_method_has_execute_failed>`\ (\ ) |const|                                                                                                                                                                 |
   +---------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`Error<enum_@GlobalScope_Error>` | :ref:`parse<class_Expression_method_parse>`\ (\ expression\: :ref:`String<class_String>`, input_names\: :ref:`PackedStringArray<class_PackedStringArray>` = PackedStringArray()\ )                                                                  |
   +---------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

.. rst-class:: classref-section-separator

----

.. rst-class:: classref-descriptions-group

Descripciones de Métodos
------------------------------------------------

.. _class_Expression_method_execute:

.. rst-class:: classref-method

:ref:`Variant<class_Variant>` **execute**\ (\ inputs\: :ref:`Array<class_Array>` = [], base_instance\: :ref:`Object<class_Object>` = null, show_error\: :ref:`bool<class_bool>` = true, const_calls_only\: :ref:`bool<class_bool>` = false\ ) :ref:`🔗<class_Expression_method_execute>`

Ejecuta la expresión que fue previamente analizada por :ref:`parse()<class_Expression_method_parse>` y devuelve el resultado. Antes de usar el objeto devuelto, debería comprobar si el método falló llamando a :ref:`has_execute_failed()<class_Expression_method_has_execute_failed>`.

Si has definido las variables de entrada en :ref:`parse()<class_Expression_method_parse>`, puedes especificar sus valores en el array de entradas, en el mismo orden.

.. rst-class:: classref-item-separator

----

.. _class_Expression_method_get_error_text:

.. rst-class:: classref-method

:ref:`String<class_String>` **get_error_text**\ (\ ) |const| :ref:`🔗<class_Expression_method_get_error_text>`

Returns the error text if :ref:`parse()<class_Expression_method_parse>` or :ref:`execute()<class_Expression_method_execute>` has failed.

.. rst-class:: classref-item-separator

----

.. _class_Expression_method_has_execute_failed:

.. rst-class:: classref-method

:ref:`bool<class_bool>` **has_execute_failed**\ (\ ) |const| :ref:`🔗<class_Expression_method_has_execute_failed>`

Devuelve ``true`` si :ref:`execute()<class_Expression_method_execute>` ha fallado.

.. rst-class:: classref-item-separator

----

.. _class_Expression_method_parse:

.. rst-class:: classref-method

:ref:`Error<enum_@GlobalScope_Error>` **parse**\ (\ expression\: :ref:`String<class_String>`, input_names\: :ref:`PackedStringArray<class_PackedStringArray>` = PackedStringArray()\ ) :ref:`🔗<class_Expression_method_parse>`

Parses the expression and returns an :ref:`Error<enum_@GlobalScope_Error>` code.

You can optionally specify names of variables that may appear in the expression with ``input_names``, so that you can bind them when it gets executed.

.. |virtual| replace:: :abbr:`virtual (Normalmente, este método debería ser sobreescrito por el usuario para que tenga algún efecto.)`
.. |required| replace:: :abbr:`required (This method is required to be overridden when extending its base class.)`
.. |const| replace:: :abbr:`const (Este método no tiene efectos secundarios. No modifica ninguna de las variables miembro de la instancia.)`
.. |vararg| replace:: :abbr:`vararg (Este método permite agregar cualquier número de argumentos después de los descritos aquí.)`
.. |constructor| replace:: :abbr:`constructor (Este método se utiliza para construir un tipo.)`
.. |static| replace:: :abbr:`static (Este método no necesita una instancia para ser llamado, por lo que puede llamarse directamente utilizando el nombre de la clase.)`
.. |operator| replace:: :abbr:`operator (Este método describe un operador válido para usar con este tipo como operando izquierdo.)`
.. |bitfield| replace:: :abbr:`BitField (Este valor es un entero compuesto como una máscara de bits de las siguientes banderas.)`
.. |void| replace:: :abbr:`void (Sin valor de retorno.)`