mirror of
https://github.com/godotengine/godot-docs.git
synced 2026-01-03 05:48:42 +03:00
126 lines
6.1 KiB
ReStructuredText
126 lines
6.1 KiB
ReStructuredText
:github_url: hide
|
|
|
|
.. Generated automatically by doc/tools/make_rst.py in Godot's source tree.
|
|
.. DO NOT EDIT THIS FILE, but the Expression.xml source instead.
|
|
.. The source is found in doc/classes or modules/<name>/doc_classes.
|
|
|
|
.. _class_Expression:
|
|
|
|
Expression
|
|
==========
|
|
|
|
**Inherits:** :ref:`RefCounted<class_RefCounted>` **<** :ref:`Object<class_Object>`
|
|
|
|
A class that stores an expression you can execute.
|
|
|
|
Description
|
|
-----------
|
|
|
|
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.connect("text_submitted", 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
|
|
|
|
public Expression expression = new Expression();
|
|
|
|
public override void _Ready()
|
|
{
|
|
GetNode("LineEdit").Connect("text_submitted", this, nameof(OnTextEntered));
|
|
}
|
|
|
|
private void OnTextEntered(string command)
|
|
{
|
|
Error error = expression.Parse(command);
|
|
if (error != Error.Ok)
|
|
{
|
|
GD.Print(expression.GetErrorText());
|
|
return;
|
|
}
|
|
object result = expression.Execute();
|
|
if (!expression.HasExecuteFailed())
|
|
{
|
|
GetNode<LineEdit>("LineEdit").Text = result.ToString();
|
|
}
|
|
}
|
|
|
|
|
|
|
|
Methods
|
|
-------
|
|
|
|
+---------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|
|
| :ref:`Variant<class_Variant>` | :ref:`execute<class_Expression_method_execute>` **(** :ref:`Array<class_Array>` inputs=[], :ref:`Object<class_Object>` base_instance=null, :ref:`bool<class_bool>` show_error=true **)** |
|
|
+---------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|
|
| :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>` **(** :ref:`String<class_String>` expression, :ref:`PackedStringArray<class_PackedStringArray>` input_names=PackedStringArray() **)** |
|
|
+---------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|
|
|
|
Method Descriptions
|
|
-------------------
|
|
|
|
.. _class_Expression_method_execute:
|
|
|
|
- :ref:`Variant<class_Variant>` **execute** **(** :ref:`Array<class_Array>` inputs=[], :ref:`Object<class_Object>` base_instance=null, :ref:`bool<class_bool>` show_error=true **)**
|
|
|
|
Executes the expression that was previously parsed by :ref:`parse<class_Expression_method_parse>` and returns the result. Before you use the returned object, you should check if the method failed by calling :ref:`has_execute_failed<class_Expression_method_has_execute_failed>`.
|
|
|
|
If you defined input variables in :ref:`parse<class_Expression_method_parse>`, you can specify their values in the inputs array, in the same order.
|
|
|
|
----
|
|
|
|
.. _class_Expression_method_get_error_text:
|
|
|
|
- :ref:`String<class_String>` **get_error_text** **(** **)** |const|
|
|
|
|
Returns the error text if :ref:`parse<class_Expression_method_parse>` has failed.
|
|
|
|
----
|
|
|
|
.. _class_Expression_method_has_execute_failed:
|
|
|
|
- :ref:`bool<class_bool>` **has_execute_failed** **(** **)** |const|
|
|
|
|
Returns ``true`` if :ref:`execute<class_Expression_method_execute>` has failed.
|
|
|
|
----
|
|
|
|
.. _class_Expression_method_parse:
|
|
|
|
- :ref:`Error<enum_@GlobalScope_Error>` **parse** **(** :ref:`String<class_String>` expression, :ref:`PackedStringArray<class_PackedStringArray>` input_names=PackedStringArray() **)**
|
|
|
|
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 (This method should typically be overridden by the user to have any effect.)`
|
|
.. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`
|
|
.. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`
|
|
.. |constructor| replace:: :abbr:`constructor (This method is used to construct a type.)`
|
|
.. |static| replace:: :abbr:`static (This method doesn't need an instance to be called, so it can be called directly using the class name.)`
|
|
.. |operator| replace:: :abbr:`operator (This method describes a valid operator to use with this type as left-hand operand.)`
|