What name does this syntax have

Question

In the language nim, one can do the following thing:

let num = 5.add(3)

which would be the same as

let num = add(5,3)

So, basically you take the expression before the dot as the first argument to the function. I'm sure other languages have this feature, but none directly came to mind.

What I want to know is what name this syntax has

Answer 1

In D lang this syntax is called Uniform Function Call Syntax (UFCS).