Please explain return to me

What does this do? If I declare a variable like this;

Public Targetable target; (target able is another class not in this one)

And then have a method;

Public GetTarget()
{return target;}

And I call this from a separate script. Is it just referencing this class? So, a reference to Target able? In language terms, what's it "returning"? Can I set this to be an enum to be returned? So, four options in an enum in a script. Then I have one option to be "stone". I set it to stone in an if statement. Can I have that enum returned to another script?

 

return

, well, "returns" a response from a method.
In your example, yes, it's returning the reference of the "Targetable" variable.
And yes, you can return things from other classes, so if a different script calls this method, it will have this script's "Targetable" reference.

Yes, a method can return anything - you just need to define the type that it returns.

You're probably already familiar with

void

, right? That just means the method doesn't return anything after being executed. You can change

void

to any other type that you want a method to return:

Code (CSharp):

1. //This method returns nothing.
2. void Method1() { }
3.  
4. //This method returns a string.
5. string Method2() { }
6.  
7. //This method returns a float.
8. float Method3() { }
9.  
10. //This method returns a Vector3.
11. Vector3 Method4() { }
12.  
13. //This method returns a GameObject.
14. GameObject Method5() { }
15.  
16. //This method returns a Renderer.
17. Renderer Method6() { }
18.  
19. //etc...

Note that the

return

keyword will immediately stop a method's execution, so if you have something like this, for instance:

Code (CSharp):

1. float Add(float num1, float num2) {
2.    float result = num1 + num2;
3.    return result;
4.  
5.    Debug.Log("Result is: " + result);
6. }

The

Debug.Log

statement here (and anything after it) will never be run.

A method can also return another method, and all that means is that it returns the result of whatever that other method returns:

Code (CSharp):

1. float Calculate(float num1, float num2) {
2.    //This method simply returns what the "Add" method returns.
3.    return Add(num1, num2);
4. }
5.  
6. float Add(float num1, float num2) {
7.    float result = num1 + num2;
8.    return result;
9. }

If a method returns an object, any other object-type that inherits from that object can be returned as well.
For example, Unity's

BoxCollider

,

SphereCollider

,

CapsuleCollider

and other colliders all inherit from the

Collider

class.
So if a method returns a

Collider

type, any type of collider can be returned:

Code (CSharp):

1. public class Example : MonoBehavior {
2.    public BoxCollider box;
3.    public SphereCollider sphere;
4.    public CapsuleCollider capsule;
5.  
6.    public Collider GetColliderByIndex(int index) {
7.       if(index == 0) {
8.          return box;
9.       }
10.       else if(index == 1) {
11.          return sphere;
12.       }
13.       else if(index == 2) {
14.          return capsule;
15.       }
16.       else {
17.          return null;
18.       }
19.    }
20. }

Finally, you can also use the

return

keyword in

void

methods as well if you wish to stop their execution. For example:

Code (CSharp):

1. void Jump(float stamina) {
2.    if(stamina < 25f) {
3.       //Cannot jump if stamina is too low. Just stop the method immediately.
4.       return;
5.    }
6.  
7.    //The code down here will only be run if "stamina" is greater than 25f.
8.    transform.position = //etc...
9. }

 

Ok, that's awesome. Thank you.