Update some of the C# documentation for 4.0 (#6681)

* Update C# documentation for 4.0

---------

Co-authored-by: Yuri Sizov <11782833+YuriSizov@users.noreply.github.com>

tutorials/scripting/c_sharp/c_sharp_basics.rst

@@ -82,6 +82,7 @@ external editor of choice. Godot currently supports the following
 external editors:
 
 - Visual Studio 2019
+- Visual Studio 2022
 - Visual Studio Code
 - MonoDevelop
 - Visual Studio for Mac
@@ -187,10 +188,11 @@ Project setup and workflow
 When you create the first C# script, Godot initializes the C# project files
 for your Godot project. This includes generating a C# solution (``.sln``)
 and a project file (``.csproj``), as well as some utility files and folders
-(``.mono`` and ``Properties/AssemblyInfo.cs``).
-All of these but ``.mono`` are important and should be committed to your
-version control system. ``.mono`` can be safely added to the ignore list of your VCS.
-When troubleshooting, it can sometimes help to delete the ``.mono`` folder
+(``.godot/mono``).
+All of these but ``.godot/mono`` are important and should be committed to your
+version control system. Everything under ``.godot`` can be safely added to the
+ignore list of your VCS.
+When troubleshooting, it can sometimes help to delete the ``.godot/mono`` folder
 and let it regenerate.
 
 Example
@@ -248,8 +250,9 @@ For more information, see the :ref:`doc_c_sharp_differences` page.
     You need to (re)build the project assemblies whenever you want to see new
     exported variables or signals in the editor. This build can be manually
     triggered by clicking the word **Build** in the top right corner of the
-    editor. You can also click **Mono** at the bottom of the editor window
-    to reveal the Mono panel, then click the **Build Project** button.
+    editor. You can also click **MSBuild** at the bottom of the editor window
+    to reveal the MSBuild panel, then click the **Build** button to reveal a
+    dropdown, then click the **Build Solution** option.
 
     You will also need to rebuild the project assemblies to apply changes in
     "tool" scripts.
@@ -261,7 +264,7 @@ As C# support is quite new in Godot, there are some growing pains and things
 that need to be ironed out. Below is a list of the most important issues
 you should be aware of when diving into C# in Godot, but if in doubt, also
 take a look over the official
-`issue tracker for Mono issues <https://github.com/godotengine/godot/labels/topic%3Amono>`_.
+`issue tracker for .NET issues <https://github.com/godotengine/godot/labels/topic%3Adotnet>`_.
 
 - Writing editor plugins is possible, but it is currently quite convoluted.
 - State is currently not saved and restored when hot-reloading,
@@ -274,11 +277,13 @@ take a look over the official
   So when using e.g. ``CallDeferred("AddChild")``, ``AddChild`` will not work because
   the API is expecting the original ``snake_case`` version ``add_child``. However, you
   can use any custom properties or methods without this limitation.
+  Prefer using the exposed ``StringName`` in the ``PropertyName``, ``MethodName`` and
+  ``SignalName`` to avoid extra ``StringName`` allocations and worrying about snake_case naming.
 
 
-As of Godot 3.2.2, exporting Mono projects is supported for desktop platforms
-(Linux, Windows and macOS), Android, HTML5, and iOS. The only platform not
-supported yet is UWP.
+As of Godot 4.0, exporting .NET projects is supported for desktop platforms
+(Linux, Windows and macOS). Other platforms will gain support in future 4.x
+releases.
 
 Performance of C# in Godot
 --------------------------
@@ -299,7 +304,7 @@ a single code location:
 
     using Godot;
 
-    public class YourCustomClass : Node3D
+    public partial class YourCustomClass : Node3D
     {
         private void ExpensiveReposition()
         {

tutorials/scripting/c_sharp/c_sharp_differences.rst

@@ -34,7 +34,6 @@ Special cases:
 =======================  ===========================================================
 GDScript                 C#
 =======================  ===========================================================
-``SPKEY``                ``GD.SpKey``
 ``TYPE_*``               ``Variant.Type`` enum
 ``OP_*``                 ``Variant.Operator`` enum
 =======================  ===========================================================
@@ -46,17 +45,29 @@ Math global functions, like ``abs``, ``acos``, ``asin``, ``atan`` and ``atan2``,
 located under ``Mathf`` as ``Abs``, ``Acos``, ``Asin``, ``Atan`` and ``Atan2``.
 The ``PI`` constant can be found as ``Mathf.Pi``.
 
+C# also provides static `System.Math`_ and `System.MathF`_ classes that may
+contain other useful mathematical operations.
+
+.. _System.Math: https://learn.microsoft.com/en-us/dotnet/api/system.math
+.. _System.MathF: https://learn.microsoft.com/en-us/dotnet/api/system.mathf
+
 Random functions
 ^^^^^^^^^^^^^^^^
 
 Random global functions, like ``rand_range`` and ``rand_seed``, are located under ``GD``.
 Example: ``GD.RandRange`` and ``GD.RandSeed``.
 
+Consider using `System.Random`_ or, if you need cryptographically strong randomness,
+`System.Security.Cryptography.RandomNumberGenerator`_.
+
+.. _System.Random: https://learn.microsoft.com/en-us/dotnet/api/system.random
+.. _System.Security.Cryptography.RandomNumberGenerator: https://learn.microsoft.com/en-us/dotnet/api/system.security.cryptography.randomnumbergenerator
+
 Other functions
 ^^^^^^^^^^^^^^^
 
-Many other global functions like ``print`` and ``var2str`` are located under ``GD``.
-Example: ``GD.Print`` and ``GD.Var2Str``.
+Many other global functions like ``print`` and ``var_to_str`` are located under ``GD``.
+Example: ``GD.Print`` and ``GD.VarToStr``.
 
 Exceptions:
 
@@ -87,10 +98,10 @@ Example:
         }
     }
 
-Export keyword
---------------
+``@export`` annotation
+----------------------
 
-Use the ``[Export]`` attribute instead of the GDScript ``export`` keyword.
+Use the ``[Export]`` attribute instead of the GDScript ``@export`` annotation.
 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.
 
@@ -115,8 +126,10 @@ Example:
         private string _icon;
     }
 
-Signal keyword
---------------
+See also: :ref:`doc_c_sharp_exports`.
+
+``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.
@@ -185,8 +198,8 @@ Example:
 
 .. code-block:: csharp
 
-    string text = "Bigrams";
-    string[] bigrams = text.Bigrams(); // ["Bi", "ig", "gr", "ra", "am", "ms"]
+    string text = "Get up!";
+    string[] bigrams = text.Bigrams(); // ["Ge", "et", "t ", " u", "up", "p!"]
 
 Strings are immutable in .NET, so all methods that manipulate a string don't
 modify the original string and return a newly created string with the
@@ -486,22 +499,52 @@ Use the ``Godot.Collections.Dictionary<T>(Godot.Collections.Dictionary)`` constr
 Variant
 -------
 
-``System.Object`` (``object``) is used instead of ``Variant``.
+``Godot.Variant`` is used to represent the Godot's native :ref:`Variant <doc_variant_class>` type. Any Variant-compatible type can be converted from/to it.
+We recommend avoiding ``Godot.Variant`` unless it is necessary to interact with untyped engine APIs.
+Take advantage of C#'s type safety when possible.
+
+Any of ``Variant.As{TYPE}`` methods or the generic ``Variant.As<T>`` method can be used to convert
+a ``Godot.Variant`` to a C# type. Since the ``Godot.Variant`` type contains implicit conversions
+defined for all the supported types calling these methods directly is usually not necessary.
+
+Use ``CreateFrom`` method overloads or the generic ``From<T>`` method to convert a C# type
+to a ``Godot.Variant``.
 
 Communicating with other scripting languages
 --------------------------------------------
 
 This is explained extensively in :ref:`doc_cross_language_scripting`.
 
-.. _doc_c_sharp_differences_yield:
+.. _doc_c_sharp_differences_await:
 
-Yield
------
+``await`` keyword
+-----------------
 
-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>`_.
+Something similar to GDScript's ``await`` keyword can be achieved with C#'s
+`await keyword <https://docs.microsoft.com/en-US/dotnet/csharp/language-reference/keywords/await>`_.
 
-The equivalent of yield on signal can be achieved with async/await and ``Godot.Object.ToSignal``.
+The ``await`` keyword in C# can be used with any awaitable expression. It's commonly
+used with operands of the types `Task`_, `Task<TResult>`_, `ValueTask`_, or `ValueTask<TResult>`_.
+
+An expression ``t`` is awaitable if one of the following holds:
+
+* ``t`` is of compile-time type ``dynamic``.
+* ``t`` has an accessible instance or extension method called ``GetAwaiter`` with no
+  parameters and no type parameters, and a return type ``A`` for which all of the
+  following hold:
+
+  * ``A`` implements the interface ``System.Runtime.CompilerServices.INotifyCompletion``.
+  * ``A`` has an accessible, readable instance property ``IsCompleted`` of type ``bool``.
+  * ``A`` has an accessible instance method ``GetResult`` with no parameters and no type
+    parameters.
+
+.. _Task: https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task
+.. _Task<TResult>: https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task-1
+.. _ValueTask: https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.valuetask
+.. _ValueTask<TResult>: https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.valuetask-1
+
+An equivalent of awaiting a signal in GDScript can be achieved with the ``await`` keyword and
+``Godot.Object.ToSignal``.
 
 Example:
 
@@ -522,8 +565,13 @@ Other differences:
 GDScript          C#
 ================  ==================================================================
 ``Color8``        ``Color.Color8``
-``is_inf``        ``float.IsInfinity``
-``is_nan``        ``float.IsNaN``
-``dict2inst``     TODO
-``inst2dict``     TODO
+``is_inf``        `float.IsInfinity`_ or `double.IsInfinity`_
+``is_nan``        `float.IsNaN`_ or `double.IsNaN`_
+``dict_to_inst``  TODO
+``inst_to_dict``  TODO
 ================  ==================================================================
+
+.. _float.IsInfinity: https://learn.microsoft.com/en-us/dotnet/api/system.single.isinfinity
+.. _float.IsNaN: https://learn.microsoft.com/en-us/dotnet/api/system.single.isnan
+.. _double.IsInfinity: https://learn.microsoft.com/en-us/dotnet/api/system.double.isinfinity
+.. _double.IsNaN: https://learn.microsoft.com/en-us/dotnet/api/system.double.isnan

tutorials/scripting/c_sharp/c_sharp_signals.rst

@@ -21,7 +21,7 @@ You can handle these events, as any other event, with the ``+=`` and ``-=`` oper
     myTimer.Timeout += () => GD.Print("Timeout!");
 
 In addition, you can always access signal names associated with a node type through its nested
-``SignalName`` class. This is useful when, for example, you want to await on a signal (see :ref:`doc_c_sharp_differences_yield`).
+``SignalName`` class. This is useful when, for example, you want to await on a signal (see :ref:`doc_c_sharp_differences_await`).
 
 .. code-block:: csharp