Uniform function call syntax

Uniform Function Call Syntax (UFCS) is a programming language feature in D that allows any function to be called on an object (as in Object-oriented programming) like the function is a method of its class. UFCS is particularly useful when function calls are chained.

Examples

import std.stdio;

int first(int[] arr)
{
    return arr[0];
}

int[] addone(int[] arr)
{
    int[] result;
    foreach (value; arr) {
        result ~= value + 1;
    }
    return result;
}

void main()
{
    auto a = [0, 1, 2, 3];

    // All the followings are correct and equivalent
    int b = first(a);
    int c = a.first();
    int d = a.first;

    // Chaining
    int[] e = a.addone().addone();
}