What is "ref" in C# and its analog in UnityScript?

How can I rewrite it in UnityScript?

Code (csharp):

1. public static bool FileBrowser( ref string location, ref Vector2 directoryScroll, ref Vector2 fileScroll )
2.  

Thanks

 

You can't; there's no way to specify a reference parameter in Unityscript functions.

--Eric

 

there is no analog to it in unity script

if you meet such a thing you can use it with C# only, for UnityScript you would require a function that returns the location.

ref / out are special parameters to pass reference to references into functions so you can assign new objects to it.
you can find out more on it in any C# book or through google, there are a few hundred articles on the matter offering you different explaination approaches

 

Ah ok, basically I am trying to rewrite the file browser code in javascript.
http://www.unifycommunity.com/wiki/index.php?title=FileBrowser
Is it possible in principle or what is there is possible only with C#?

 

it works in general, but you can not return the complete, instead you would return the path (location) for example

 

Thanks, guys!

One minor thing, what did you mean by "but you can not return the complete"?

 

means that at the end of the function you would return the location, not a boolean that indicates complete or incomplete

 

I guess you can have the ref effect by casting all your parameters as "object", though I don't know much about Unity Script.

Something like...

Code (csharp):

1.  
2. public static bool FileBrowser( object loc, object dirScroll, object fScroll )
3. {
4. stirng location1 = (string) loc;
5. Vector2 directorySroll1 = (Vector2)dirScroll;
6. Vector3 fireScroll1 = (Vector2)fScroll;
7. }
8.  

The calling side...

Code (csharp):

1.  
2. string loctaion;
3. Vector2 directoryScroll;
4. Vector2 fireScroll;
5.  
6. FileBrowser( (object)loc, (object)directoryScroll, (object)fireScroll);
7.  

Again, I don't know much about how Unity Script converts primitive values into objects. But I think that there should be a way for you to convert anything into objects. In C#, everything is rooted on the object class naturally that you should be able to convert whatever into an object.

 

That has nothing to do with ref at all.

ref allows you to assign a new object to the loc within the function, even generate a whole new object.
this can not be done through any other meaning (aside of out which is c# only too).

as such to get a comparable effect with UnityScript, you must change the return of the function to string and return complete; must become return location;

 

That's not how it works, not even in C#. If you want a variable to be passed by reference, you have to specify "ref" or else use a variable type that's inherently passed by reference.

--Eric

 

I will try all suggestions, thanks

 

Actually, the 'ref' keyword has nothing to do with whether the value being passed is a reference type or not. Its effect is on how assignments to the formal parameter within the called function affect variable that was passed in the function call.

To the OP: as stated above, there is no equivalent to declare a 'ref' parameter in UnityScript (so you can't write a function that operates like that); but UnityScript does support 'ref' semantics when calling functions defined that way in C#. So you can call the existing C# implementation as it is, without re-writing it in UnityScript, just fine. If you're re-writing it for instructional/learning purposes, then you'll need to make changes to the API to accommodate the limitation in UnityScript. But if you just want a file browser you can call from UnityScript, use the existing C# code as is. Just make sure the script is in a folder where it will be compiled before your calling script (i.e. put it into a folder named Plugins or Standard Assets (amoung others)).

 

I didn't say that it did. A sort of hack which more or less gets the results of using "ref" in JS is to use a reference type instead of a value type.

Code (csharp):

1. class RefString {
2.     var s : String;
3.     function RefString (value : String) {
4.         s = value;
5.     }
6. }

Use that instead of a string and you basically get the effect of declaring "ref" with a string parameter in a function, since classes are always passed by reference.

--Eric

 

what are variable types that are passed by reference?
An instance of a class maybe? what else

 

Classes are passed by reference; primitive types and structs are passed by value.

--Eric

 

The way i understand it is, even though vanilla c# does this, the ref keyWord cant be used in unity's uniscript to pass primitive types as references. Did i word that accurately?

I swear i have seen ref used in a second class made inside a script.

Code (csharp):

1.  
2. using UnityStuff
3.    public class ScriptName:Monobehaviour{
4.    public int value=stuff;
5.    public whatKindOfClassIsThis instanceOfSomeKindOfCustomClass;
6.    void Start(){
7.    ModReference(value);
8.       instanceOfSomeKindOfCustomClass.ModReference(value);
9.    }
10.    void ModReference(ref int val){//cant use ref here, maybe because it derives from MonoBehaviour?
11.       val=otherStuff;
12.    }
13. }
14. public class whatKindOfClassIsThis?{
15.    void ModReference(ref int val){//can use ref here? why?
16.       val=otherStuff;
17.    }
18. }
19.  

 

You can use ref in C# just fine. You can call C# functions that use ref from Unityscript just fine too; the ref is implied in that case since you can't write it explicitly. (Same deal for "out"; see Physics.Raycast in Unity for example.) What you can't do is declare ref or out in Unityscript functions directly. Note that Unityscript and C# are different languages.

--Eric