functional programming - Is there idiomatic C# equivalent to C's comma operator?

Question

I'm using some functional stuff in C# and keep getting stuck on the fact that List.Add doesn't return the updated list.

In general, I'd like to call a function on an object and then return the updated object.

For example it would be great if C# had a comma operator:

((accum, data) => accum.Add(data), accum)

I could write my own "comma operator" like this:

static T comma(Action a, Func<T> result) {
    a();
    return result();
}

It looks like it would work but the call site would ugly. My first example would be something like:

((accum, data) => comma(accum.Add(data), ()=>accum))

Enough examples! What's the cleanest way to do this without another developer coming along later and wrinkling his or her nose at the code smell?

Answer 1

I know this as Fluent.

A Fluent example of a List.Add using Extension Methods

static List<T> MyAdd<T>(this List<T> list, T element)
{
    list.Add(element);
    return list;
}