• Dennis Ritchie (20/20) Mar 11 2015 Hi.
• Namespace (17/17) Mar 11 2015 import std.stdio;
• Namespace (18/18) Mar 11 2015 Or even shorter:
• Rikki Cattermole (20/40) Mar 11 2015 Just to declare I don't know c++. So this is just guessing.
• Dennis Ritchie (1/1) Mar 11 2015 Thank you all.

"Dennis Ritchie" <dennis.ritchie mail.ru> writes:

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
}

"Namespace" <rswhite4 gmail.com> writes:

import std.stdio;

T foo(T)(auto ref const T val)
{
     return val;
}

T foo(T, Args...)(auto ref const T val, auto ref const Args u)
{
	static if (is(T == string))
     	return val ~ foo(u);
     else
     	return val + foo(u);
}

void main()
{
     writeln(foo("some ", "test")); // prints some test
     writeln(foo(2, 2, 1));		// prints 5
}

"Namespace" <rswhite4 gmail.com> writes:

Or even shorter:

import std.stdio;

T foo(T, Args...)(auto ref const T val, auto ref const Args u)
{
     static if (Args.length > 0) {
         static if (is(T == string))
             return val ~ foo(u);
         else
             return val + foo(u);
     } else {
         return val;
     }
}

void main()
{
     writeln(foo("some ", "test")); // prints some test
     writeln(foo(2, 2, 1));      // prints 5
}

Rikki Cattermole <alphaglosined gmail.com> writes:

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));
}

"Dennis Ritchie" <dennis.ritchie mail.ru> writes:

Thank you all.