Static type inclusions VNext

Static type inclusions

The Java programming language is able to do a static type inclusion. Additionally some people familiar with .NET already know that VB is also capable of doing this. Static type inclusion means that the methods defined in a static class (also called procedures and functions) can be invoked, without specifying the name of the static class for each call. So this is like seeing the static class as a namespace. In this sense the static type inclusion is a possibility of using this "namespace".

What kind of scenarios are therefore possible? Let's first think about a class with a high usage of math functions. Usually one would be required to write something like:

class Abc
{
    /* ... */

    public double ComputeNumber(double x)
    {
        var ae = Math.Exp(-alpha * x);
        var cx = Math.Cos(x);
        var sx = Math.Sin(x);
        var sqrt = Math.Sqrt(ae * sx);
        var square = Math.Pow(ae * cx, 2.0);
        return Math.PI * square / sqrt;
    }
}

Static type inclusions lets us now tell the compiler that we want to act as if the functions (in this case Exp, Cos, ...) would have been defined in this class, Abc. How does this look?

using System.Math;

class Abc
{
    /* ... */

    public double ComputeNumber(double x)
    {
        var ae = Exp(-alpha * x);
        var cx = Cos(x);
        var sx = Sin(x);
        var sqrt = Sqrt(ae * sx);
        var square = Pow(ae * cx, 2.0);
        return PI * square / sqrt;
    }
}

This feature is highly controversial and might lead to strange code and ambiguities. However, in the end one should decide if it is really worth using this feature from case to case. If the inclusion imports functions with names like Do,Create, Perform or Install then confusion is probably part of the game. If math functions are imported the decision is quite obvious.