Chain of Events using Coroutine

I'm new to coroutines, but I think what I'm wanting to do here is a good use for them, I just can't figure out how to do it. What I want to do is create a sort of wizard, where you step through a multi-step process each time the user clicks a button. I have created a rough sketch that I think conveys what I mean:



How do I set up a coroutine to sit and loop on a step until the mouse is clicked, then move on to the next step. While in the 'wizard' portion of the code, "Do Something" should not execute.

I know how I can do this using boolean flags or an integer to represent what 'step' I'm on, but I'd like to avoid that if possible.

Thanks

 

A pretty simple setup:

Code (csharp):

1. function ButtonLoop() {
2.   var currentStage: int = 0;
3.   var done : int = 4;
4.   while ( currentStage < done ) {
5.     currentStage = Display( currentStage );
6.     yield;
7.   }
8. }
9.  
10. function Display( currentStage : int ) : int {
11.   var returnValue : int = currentStage
12.   switch( currentStage ) {
13.      case 1:
14.         // display/check button status, set returnValue to 2 if "next" was pressed, 0 if "back" was pressed
15.         break;
16.      /*...*/
17.   }
18.   return returnValue;
19. }

If you're dead-set against state variables, you can jam it all into the coroutine:

Code (csharp):

1. function ButtonLoop() {
2.   while( !done ) {
3.     // do stage one, set done when done
4.     yield;
5.   }
6.   while( !done ) {
7.     // do stage two, set done when done
8.     yield;
9.   }
10.   while( !done ) {
11.     // do stage three, set done when done
12.     yield;
13.   }
14. }

There will be complications with that, but they'll be fixable. (going back will be difficult, for example)

Edit: If you're using OnGUI, you already essentially -have- your coroutine, since it has to run all the time anyway. It's easiest to use a state machine with OnGUI.