Re: Taking a constant reference to a constant/non const object

[helxi via Digitalmars-d-learn]

On Wednesday, 15 November 2017 at 09:34:32 UTC, helxi wrote:
On Wednesday, 15 November 2017 at 09:23:53 UTC, Jonathan M 
Davis wrote:
On Wednesday, November 15, 2017 09:04:50 helxi via 
Digitalmars-d-learn wrote:
Hi. What function signature should I use for receiving a 
constant
reference of an r/l value object? Is it auto fn(inout ref 
const
myClass obj)?
I want to:
1. Take a constant reference of the object, not copy them
2. The object itself may be const or non const.

ref const(Type) would be the const version of ref Type. e.g.

auto foo(ref const(int) i) {...}

- Jonathan M Davis

Thanks. Just a couple of follow-ups:
1. I've never seen a signature like `const(int)`is the 
enclosing parenthesis around the `int` necessary?
2. What effects does prefixing the arguments with `inout` have? 
For example:  fn(inout ref const string str){...}

Terribly sorry for my bad choice of words. Basically I want to 
utilize D's "inout" to avoid writing two functions like this:

#include <iostream>
#include <string>

void fn(std::string& str) {
  std::cout << str << " called from fn(std::string& str)"
            << "\n ";
}

void fn(const std::string& str) {
  std::cout << str << " alled from fn(const std::string& str)"
            << "\n";
}

int main() {
  fn("Test 1");
  std::string b = "test";
  b += " 2";
  fn(b);
}