c# generic with slight difference for types?

Question

Notice the two extensions, one for float, one for Vector3.

Notice there\'s only a slight difference in the var( call.

In c# could these be writt

Answer 1

You can do it if you make an extra Func that performs transformation before calling the var action (which you should rename, because var is a C# keyword).

Here is one approach that you could take:

public static IEnumerator Tweeng(
    this float duration
,   System.Action varAction
,   T aa
,   T zz
) {
    Func transform = MakeTransform();
    float sT = Time.time;
    float eT = sT + duration;
    while (Time.time < eT) {   
        float t = (Time.time-sT)/duration;
        varAction(transform(aa, zz, t));
        yield return null;
    }
    varAction(zz);
}

private static Func MakeTransform() {
    if (typeof(T) == typeof(float)) {
        Func f = Mathf.SmoothStep;
        return (Func)(Delegate)f;
    }
    if (typeof(T) == typeof(Vector3)) {
        Func f = Vector3.Lerp;
        return (Func)(Delegate)f;
    }
    throw new ArgumentException("Unexpected type "+typeof(T));
}

It can even be done inline:

public static IEnumerator DasTweeng( this float duration, System.Action vary, T aa, T zz )
    {
    float sT = Time.time;
    float eT = sT + duration;

    Func step;

    if (typeof(T) == typeof(float))
        step = (Func)(Delegate)(Func)Mathf.SmoothStep;
    else if (typeof(T) == typeof(Vector3))
        step = (Func)(Delegate)(Func)Vector3.Lerp;
    else
        throw new ArgumentException("Unexpected type "+typeof(T));

    while (Time.time < eT)
        {
        float t = (Time.time-sT)/duration;
        vary( step(aa,zz, t) );
        yield return null;
        }
    vary(zz);
    }

Perhaps a more natural idiom is

    Delegate d;

    if (typeof(T) == typeof(float))
        d = (Func)Mathf.SmoothStep;
    else if (typeof(T) == typeof(Vector3))
        d = (Func)Vector3.Lerp;
    else
        throw new ArgumentException("Unexpected type "+typeof(T));

    Func step = (Func)d;