How do I default a c# Func optional parameter [duplicate]

Question

I would like a Func<float,float> parameter to a method but default it to a static function:

public Animation(float timeForAnimation,Vector target, Func<float, float> ease = Ease.nothing)

where Ease.nothing is a static function:

 public static float nothing(float f)
        {
            return MathUtil.clamp(0, f, 1);
        }

I am getting an error: 'Default parameter value for 'ease' must be a compile-time constant' .. not sure what that means or how i can get it to work

Answer 1

You don't. Default values of parameters must be constants. In this case, the only such a constant is null.

What you can do, is resolve that within the body of Animation.

public void Animation(float timeForAnimation,Vector target, Func<float, float> ease = null)
{
    // in case of 'null' call the default Ease.Nothing() method
    var easedTime = (ease ?? Ease.Nothing)(timeForAnimation);
}

Side note: Let me suggest you stick to the UpperCamelCase naming convention for method names.