Template. C++ to D

[Rikki Cattermole via Digitalmars-d-learn]

On 12/03/2015 1:02 a.m., Dennis Ritchie wrote:
> Hi.
> How to rewrite this code on D?
>
> #include <string>
> #include <iostream>
>
> template <typename T>
> T foo(const T &val)
> {
>      return val;
> }
>
> template <typename T, typename ...U>
> T foo(const T &val, const U &...u)
> {
>      return val + foo(u...);
> }
>
> int main()
> {
>      std::cout << foo(std::string("some "), std::string("test")) <<
> std::endl;    // prints some test
>      std::cout << foo(2, 2, 1) << std::endl;        // prints 5
> }

Just to declare I don't know c++. So this is just guessing.

T foo(T)(ref const(T) val) { // val does not need to be ref here!
	return cast()val; // remove const
}

T foo(T, U)(ref const(T) val, ref const(U)[] u...) { // again don't need 
ref/const
	import std.algorithm : map;
	return cast()val + map!((v) => cast()foo(v))(u); // ugg so basically a 
sum of all elements of u? ok std.algorithm has sum function for this. 
Also removes const

	// import std.algorithm : sum;
	// return val + u.sum;
}

void main() {
	import std.stdio : writeln;
	writeln("some ", "test"); // definitely shouldn't be separated out into 
two different strings
	writeln(foo(2, 2, 1));
}