WaitWhile.cs

using System;                                                                  
using UnityEngine;                                                             
        
// Wait for a simple boolean predicate to be true. Example: 
//
// private IEnumerator HandleDeath() {
//     yield return new WaitWhile(() => hitPoints != 0);
//     Instantiate(SuperCoolDeathFXPrefab);
// }
//
class WaitWhile : CustomYieldInstruction                                   
{                                                                          
    private Func<bool> predicate;                                          

    public override bool keepWaiting { get { return predicate(); } }       

    public WaitWhile(Func<bool> predicate) { this.predicate = predicate; } 
}