Question

Suppose I want to write a function like the following (as usual, a trivial example for illustrative purposes):

Public Function calcSqSum(Of T)(ByVal list As IEnumerable(Of T)) As T
    Dim sumSq As T

    For Each item As T In list
        sumSq += (item * item)
    Next

    Return sumSq
End Function

As you can probably guess, this function causes an error because a generic object is not guaranteed to implement the + operator. As far as I know, though, any numerical type (Integer, Double, Decimal, etc.) will.

Is there a way to write a (quasi-)generic function that can accept any numerical type, without having to explicitly overload the function for every such type yourself?

Alternatively, I suppose an equally acceptable solution would be to somehow check if a type implements the ‘+’ operator (or any operator generally associated with numerical types and used by the function).

Answer 1

No, since there’s no specific common interface that all of them implement. In essence, there’s no real notion of “numerical types” in the framework. Unless you wrap them in self-defined classes and have your method accept only your types (which is not really a direct answer to your question, just a workaround).