Pass a function(float) as variable

Question

So I have this simple function:

 function FadeIn(speed : float){
     fadeSpeed = speed;
     fadeDir = -1;
 }

and I want to add it to a class by doing something like this:

 //The class type
 class ScriptStep {
     var subScript : List.<ScriptStep>;
     var stepHoldLength : float;
     var stepTransform : Transform;
     var audioClip : AudioClip;
     var textLine : String;
     var stepFade : function(float);
 
 //And the function
 function AddStep (currentScript : List.<ScriptStep>, stepFade : function(float)){
     var step = new ScriptStep ();
         step.stepFade = stepFade;
     currentScript.Add(step);
 }

But whenever I try to actually run it:

 AddStep (gameIntro, dialogInteractions.FadeIn(0));

I keep getting the error:

 No appropriate version of 'Dialog_Manager.AddStep' for the argument list '(System.Collections.Generic.List., void)' was found.

What am I doing wrong exactly? A bit new to javascript and just started to learn how to declare variables of the type function...

Any help very appreciated!

Answer 1

Best Answer

Answer by Eric5h5 · Jul 07, 2013 at 01:59 AM

Your code should be:

 AddStep (gameIntro, dialogInteractions.FadeIn);

You can't pass in an argument when you're adding a function as a variable. You can only use an argument when you actually call the function, such as

 step.stepFade(0);

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castor · Jul 07, 2013 at 02:02 AM 0

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Gotcha!! Its working now :) Thanks.

Eric5h5 · Jul 07, 2013 at 02:12 AM 0

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By the way, if you want to be 100% explicit then you can do

 var stepFade : function(float):void;

in order to specify the return value of the function. It's void by default so it works without it, but anyway.

castor · Jul 07, 2013 at 02:16 AM 0

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BTW, what is the right way to declare the variable for the function?

 var action : Function;
 var action : function ();

castor · Jul 07, 2013 at 02:49 AM 0

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Ok...it still doesnt seem to work... this is what I have now:

 var stepActionFloat : function(float):void;
 
 function AddStep (currentScript : List.<ScriptStep>, stepAction : function (float) : void, duration : float){
     var step = new ScriptStep ();
         step.stepActionFloat = stepAction(duration);
     currentScript.Add(step);
 }

and I get a

 BCE0022: Cannot convert 'void' to 'function(): void'.

castor · Jul 07, 2013 at 02:56 AM 0

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Is it because I'm adding it as a variable again? I think I understand...Only when I call it! Super clear answer.

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Answer 2

Answer by umangindianic · Jul 05, 2013 at 04:46 AM

Use of file in top of the script.

using System.Collection.Generic;

this is use for the List which is used by you in your script.

List can not add any type of whole function but it can add the value of function. So, make your function with its return type.

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castor · Jul 07, 2013 at 01:35 AM 0

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You mean import System.Collections.Generic; right?

I'm not sure I understand what you mean by "List can not add any type of whole function but it can add the value of function." The function that I want to use (FadeIn) doesn't return anything, it just does a couple of steps, what should I ask for it to return?

castor · Jul 07, 2013 at 01:49 AM 0

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I noticed that I can make it work if the function doesnt pass a value. For example if I have this function :

 function UnPauseGame (){
     worldisUnpausedTime = Time.time;
     worldIsPaused = false;
 }

I would also get an error, but if I add a "yield to the end of it:

     function UnPauseGame (){
         worldisUnpausedTime = Time.time;
         worldIsPaused = false;
         
         yield;
     }

I can now do this: AddStep (knowsAboutJournal01, worldInteractions.UnPauseGame);

I noticed the function ends up changing from being a function () : void to function () : IEnumerator but I don't understand what that means and how it makes it acceptable to now be used.

Pass a function(float) as variable

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