New to scripting... How to set up a function library/class definition "namespace."

Unity Engine
1

I’ve found that there are several custom functions and classes I would like to be able to instantiate/use from multiple scripts without including direct references to other scripts attached to game objects. For example, I’m practicing setting up a serialization manager, but as I want this to be able to serialize classes from multiple different kinds of scripts, I realized I would need a way to pass a class object to the save manager in a format it recognizes. I’m sure there’s a fancy way of doing this kind of stuff, but I’m just hoping there’s a way I can write a script that contains class definitions and functions that I can access from all scripts so I can instantiate the class object both in the client script and instantiate a copy in the save manager for serialization and then simply pass the object to the save manager.

I’m not really up on computer science lingo - I’m thinking what I need here is a custom library? How do implement and use one of those. For example, I instantiate an object of type “List” when using System.Collections.Generic. How do I create my own namespace functions/class definitions - can these only be written in C++ or other another lower level language than C#?

2

And then pop using namespacename; at the top of of the script that should refer to it.

3

Namespace is only used to organize your code into smaller chunk.

For example, UnityEngine.Object is not the same as System.Object, and yet they are both name “Object”.

Creating a namespace is as easy as writing it;

namespace MySpace
{
    public class MyClass { }
}

Just doing that, and MyClass is part of MySpace and can be called MySpace.MyClass.

As for making a class able to react to multiple type, it’s a completely different issue. You might want to look at Generic Method; Generic Methods - C# | Microsoft Learn

Example of generic serialization;

public static void Serialize<T>(T instance)
{
    foreach (FieldInfo info in typeof(T).GetFields(BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy))
    {
        object value = info.GetValue(instance);
        // Write Value somewhere
    }
}

public static T Deserialize<T>(Stream input)
{
    T output = default(T);
    foreach (FieldInfo info in typeof(T).GetFields(BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy))
    {
        //Get value from stream
        info.SetValue(output, value);
    }
    return output;
}
4

Do I have to compile an external DLL to create my own namespace or is there a place in the Unity Project I can insert this script and it will find it when another script attempts to use the namespace? Or does it automatically know the contents of all scripts in the project?

5

You never have to compile a DLL for Unity. Simply encapsulating your script in a namespace is enough to create and assign said class to that namespace.

Let’s say I do

namespace MySpace
{
    public class MyClass { }
}

You won’t get access to MyClass from somewhere else in your code unless;

  1. You declare using that namepace;
using MySpace;
  1. Your class is within that same namespace;
namespace MySpace
{
    public class MyOtherClass { }
}
  1. You explicitly reference that namescape;
MySpace.MyClass instance = new MySpace.MyClass();

But first, read the C# documentation about namespace; Organizing types in namespaces - C# | Microsoft Learn

6

Yes, I’m just trying to determine that, if I do not compile an external DLL, where in the Unity project do I stick the “MyNamespaceDefinition.cs” file for “MyScript.cs” to be able to implement “using MyNamespace;”? Or does it matter due to the fact that Unity compiles all the scripts? Does the “MyNamespaceDefinition.cs” have to be attached to a game object to be available in a scene, for example? I’m just not to clear on how Unity evaluates the individual assets folders in the project.

7

What is “MyNamespaceDefinition.cs”? What’s in it?

8

Nevermind, it was just a “pseudocode” name for the script file that contained the namespace definition (i.e. namespace ThisNamespace { … }). The file doesn’t actually exist - I know people usually post real code that they’re trying to impliment here on the forums, I just post code I make up on the spot to try to grasp the syntax/method I must employ to get at my objective.

However, I just tried implementing a namespace by just leaving the namespace definition in a file in the assets of the project and a gameobject script seems to be able to access the namespace. So, thanks to you, I have learned that I didn’t in fact have to be working extra carefully not to make mistakes in Visual Studio to make a DLL I would add to the project. Thanks for that.