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godot-docs/getting_started/scripting/c_sharp/c_sharp_differences.rst
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.. _doc_c_sharp_differences:
C# API differences to GDScript
==============================
This is a (incomplete) list of API differences between C# and GDScript.
General differences
-------------------
As explained in the :ref:`doc_c_sharp`, C# generally uses ``PascalCase`` instead
of the ``snake_case`` used in GDScript and C++.
Global scope
------------
Global functions and some constants had to be moved to classes, since C#
does not allow declaring them in namespaces.
Most global constants were moved to their own enums.
Constants
^^^^^^^^^
Global constants were moved to their own enums.
For example, ``ERR_*`` constants were moved to the ``Error`` enum.
Special cases:
======================= ===========================================================
GDScript C#
======================= ===========================================================
``SPKEY`` ``GD.SpKey``
``TYPE_*`` ``Variant.Type`` enum
``OP_*`` ``Variant.Operator`` enum
======================= ===========================================================
Math functions
^^^^^^^^^^^^^^
Math global functions, like ``abs``, ``acos``, ``asin``, ``atan`` and ``atan2``, are
located under ``Mathf`` as ``Abs``, ``Acos``, ``Asin``, ``Atan`` and ``Atan2``.
The ``PI`` constant can be found as ``Mathf.Pi``.
Random functions
^^^^^^^^^^^^^^^^
Random global functions, like ``rand_range`` and ``rand_seed``, are located under ``GD``.
Example: ``GD.RandRange`` and ``GD.RandSeed``.
Other functions
^^^^^^^^^^^^^^^
Many other global functions like ``print`` and ``var2str`` are located under ``GD``.
Example: ``GD.Print`` and ``GD.Var2Str``.
Exceptions:
=========================== =======================================================
GDScript C#
=========================== =======================================================
``weakref(obj)`` ``Object.WeakRef(obj)``
``is_instance_valid(obj)`` ``Object.IsInstanceValid(obj)``
=========================== =======================================================
Tips
^^^^
Sometimes it can be useful to use the ``using static`` directive. This directive allows
to access the members and nested types of a class without specifying the class name.
Example:
.. code-block:: csharp
using static Godot.GD;
public class Test
{
static Test()
{
Print("Hello"); // Instead of GD.Print("Hello");
}
}
Export keyword
--------------
Use the ``[Export]`` attribute instead of the GDScript ``export`` keyword.
This attribute can also be provided with optional :ref:`PropertyHint<enum_@GlobalScope_PropertyHint>` and ``hintString`` parameters.
Default values can be set by assigning a value.
Example:
.. code-block:: csharp
using Godot;
public class MyNode : Node
{
[Export]
private NodePath _nodePath;
[Export]
private string _name = "default";
[Export(PropertyHint.Range, "0,100000,1000,or_greater")]
private int _income;
[Export(PropertyHint.File, "*.png,*.jpg")]
private string _icon;
}
Signal keyword
--------------
Use the ``[Signal]`` attribute to declare a signal instead of the GDScript ``signal`` keyword.
This attribute should be used on a `delegate`, whose name signature will be used to define the signal.
.. code-block:: csharp
[Signal]
delegate void MySignal(string willSendsAString);
See also: :ref:`doc_c_sharp_signals`.
`onready` keyword
-----------------
GDScript has the ability to defer the initialization of a member variable until the ready function
is called with `onready` (cf. :ref:`doc_gdscript_onready_keyword`).
For example:
.. code-block:: gdscript
onready var my_label = get_node("MyLabel")
However C# does not have this ability. To achieve the same effect you need to do this.
.. code-block:: csharp
private Label _myLabel;
public override void _Ready()
{
_myLabel = GetNode<Label>("MyLabel");
}
Singletons
----------
Singletons are available as static classes rather than using the singleton pattern.
This is to make code less verbose than it would be with an ``Instance`` property.
Example:
.. code-block:: csharp
Input.IsActionPressed("ui_down")
However, in some very rare cases this is not enough. For example, you may want
to access a member from the base class ``Godot.Object``, like ``Connect``.
For such use cases we provide a static property named ``Singleton`` that returns
the singleton instance. The type of this instance is ``Godot.Object``.
Example:
.. code-block:: csharp
Input.Singleton.Connect("joy_connection_changed", this, nameof(Input_JoyConnectionChanged));
String
------
Use ``System.String`` (``string``). Most of Godot's String methods are
provided by the ``StringExtensions`` class as extension methods.
Example:
.. code-block:: csharp
string upper = "I LIKE SALAD FORKS";
string lower = upper.ToLower();
There are a few differences, though:
* ``erase``: Strings are immutable in C#, so we cannot modify the string
passed to the extension method. For this reason, ``Erase`` was added as an
extension method of ``StringBuilder`` instead of string.
Alternatively, you can use ``string.Remove``.
* ``IsSubsequenceOf``/``IsSubsequenceOfi``: An additional method is provided,
which is an overload of ``IsSubsequenceOf``, allowing you to explicitly specify
case sensitivity:
.. code-block:: csharp
str.IsSubsequenceOf("ok"); // Case sensitive
str.IsSubsequenceOf("ok", true); // Case sensitive
str.IsSubsequenceOfi("ok"); // Case insensitive
str.IsSubsequenceOf("ok", false); // Case insensitive
* ``Match``/``Matchn``/``ExprMatch``: An additional method is provided besides
``Match`` and ``Matchn``, which allows you to explicitly specify case sensitivity:
.. code-block:: csharp
str.Match("*.txt"); // Case sensitive
str.ExprMatch("*.txt", true); // Case sensitive
str.Matchn("*.txt"); // Case insensitive
str.ExprMatch("*.txt", false); // Case insensitive
Basis
-----
Structs cannot have parameterless constructors in C#. Therefore, ``new Basis()``
initializes all primitive members to their default value. Use ``Basis.Identity``
for the equivalent of ``Basis()`` in GDScript and C++.
The following method was converted to a property with a different name:
==================== ==============================================================
GDScript C#
==================== ==============================================================
``get_scale()`` ``Scale``
==================== ==============================================================
Transform2D
-----------
Structs cannot have parameterless constructors in C#. Therefore, ``new Transform2D()``
initializes all primitive members to their default value.
Please use ``Transform2D.Identity`` for the equivalent of ``Transform2D()`` in GDScript and C++.
The following methods were converted to properties with their respective names changed:
==================== ==============================================================
GDScript C#
==================== ==============================================================
``get_rotation()`` ``Rotation``
``get_scale()`` ``Scale``
==================== ==============================================================
Plane
-----
The following method was converted to a property with a *slightly* different name:
================ ==================================================================
GDScript C#
================ ==================================================================
``center()`` ``Center``
================ ==================================================================
Rect2
-----
The following field was converted to a property with a *slightly* different name:
================ ==================================================================
GDScript C#
================ ==================================================================
``end`` ``End``
================ ==================================================================
The following method was converted to a property with a different name:
================ ==================================================================
GDScript C#
================ ==================================================================
``get_area()`` ``Area``
================ ==================================================================
Quat
----
Structs cannot have parameterless constructors in C#. Therefore, ``new Quat()``
initializes all primitive members to their default value.
Please use ``Quat.Identity`` for the equivalent of ``Quat()`` in GDScript and C++.
The following methods were converted to a property with a different name:
===================== =============================================================
GDScript C#
===================== =============================================================
``length()`` ``Length``
``length_squared()`` ``LengthSquared``
===================== =============================================================
Array
-----
*This is temporary. PoolArrays will need their own types to be used the way they are meant to.*
===================== ==============================================================
GDScript C#
===================== ==============================================================
``Array`` ``Godot.Collections.Array``
``PoolIntArray`` ``int[]``
``PoolByteArray`` ``byte[]``
``PoolFloatArray`` ``float[]``
``PoolStringArray`` ``String[]``
``PoolColorArray`` ``Color[]``
``PoolVector2Array`` ``Vector2[]``
``PoolVector3Array`` ``Vector3[]``
===================== ==============================================================
``Godot.Collections.Array<T>`` is a type-safe wrapper around ``Godot.Collections.Array``.
Use the ``Godot.Collections.Array<T>(Godot.Collections.Array)`` constructor to create one.
Dictionary
----------
Use ``Godot.Collections.Dictionary``.
``Godot.Collections.Dictionary<T>`` is a type-safe wrapper around ``Godot.Collections.Dictionary``.
Use the ``Godot.Collections.Dictionary<T>(Godot.Collections.Dictionary)`` constructor to create one.
Variant
-------
``System.Object`` (``object``) is used instead of ``Variant``.
Communicating with other scripting languages
--------------------------------------------
This is explained extensively in :ref:`doc_cross_language_scripting`.
Yield
-----
Something similar to GDScript's ``yield`` with a single parameter can be achieved with
C#'s `yield keyword <https://docs.microsoft.com/en-US/dotnet/csharp/language-reference/keywords/yield>`_.
The equivalent of yield on signal can be achieved with async/await and ``Godot.Object.ToSignal``.
Example:
.. code-block:: csharp
await ToSignal(timer, "timeout");
GD.Print("After timeout");
Other differences
-----------------
``preload``, as it works in GDScript, is not available in C#.
Use ``GD.Load`` or ``ResourceLoader.Load`` instead.
Other differences:
================ ==================================================================
GDScript C#
================ ==================================================================
``Color8`` ``Color.Color8``
``is_inf`` ``float.IsInfinity``
``is_nan`` ``float.IsNaN``
``dict2inst`` TODO
``inst2dict`` TODO
================ ==================================================================