Thread overview
Method-call based on template argument
May 09, 2012
nrgyzer
May 09, 2012
sclytrack
May 09, 2012
nrgyzer
May 09, 2012
I'm trying to do the following:

module myModule;

int calculate(T)(int a, int b) if(T == "add") {
   return a + b;
}

int calculate(T)(int a, int b) if(T == "subtract) {
   return a - b;
}

But when I try to run the following code, I get "template myModule.calculate" does not match any function template declaration":

void main() {

   int a = 10;
   int b = 20;
   std.stdio.writeln(calculate!("add")(a, b));
   std.stdio.writeln(calculate!("subtract")(a, b));

}

Is there any way to check if the given template argument is "add" or "subtract"? I also tried:

int calculate(string T)(int a, int b) if(T == "add") {
   return a + b;
}

int calculate(string T)(int a, int b) if(T == "subtract) {
   return a - b;
}

... without any success (I'll get an instantiation error).
May 09, 2012
On 05/09/2012 12:33 PM, nrgyzer wrote:
> void main() {
>
>     int a = 10;
>     int b = 20;
>     std.stdio.writeln(calculate!("add")(a, b));
>     std.stdio.writeln(calculate!("subtract")(a, b));
>
> }



Below works
-----------

import std.stdio;

int calculate(string T)(int a, int b) if(T == "add")
{
   return a + b;
}

int calculate(string T)(int a, int b) if(T == "subtract")
{
   return a - b;
}

void main() {

   int a = 10;
   int b = 20;
   std.stdio.writeln(calculate!("add")(a, b));
   std.stdio.writeln(calculate!("subtract")(a, b));
}


Output
------
30
-10






May 09, 2012
Hm... yes - works. I simply rewrote my method-header and it just works, too... but thanks :)