Is it somehow possible to evaluate a string on template parameters ? Something like this:

enum source = "TYPE var;";

template Eval(TYPE)
{
	string Eval()
	{
		return evaluate(source);  <-- replace TYPE with int
	}
}

mixin(Eval!int); <-- int var here


Basically I need a string mixin inserted into the template before the template parameters are evaluated.


-- 
mk

On 07/21/2013 09:26 AM, Martin Krejcirik wrote:
> Is it somehow possible to evaluate a string on template parameters ?
> Something like this:
>
> enum source = "TYPE var;";
>
> template Eval(TYPE)
> {
> 	string Eval()
> 	{
> 		return evaluate(source);  <-- replace TYPE with int
> 	}
> }
>
> mixin(Eval!int); <-- int var here
>
>
> Basically I need a string mixin inserted into the template before the
> template parameters are evaluated.
>

import std.algorithm;

enum source = "TYPE var;";

template Eval(TYPE)
{
    string Eval()
    {
        string statement = source;
        auto found = statement.findSkip("TYPE");
        assert(found);

        return TYPE.stringof ~ statement;
    }
}

void main()
{
    mixin(Eval!int);
    static assert(is (typeof(var) == int));
}

Ali

On 07/21/13 18:26, Martin Krejcirik wrote:
> Is it somehow possible to evaluate a string on template parameters ? Something like this:
> 
> enum source = "TYPE var;";
> 
> template Eval(TYPE)
> {
> 	string Eval()
> 	{
> 		return evaluate(source);  <-- replace TYPE with int
> 	}
> }
> 
> mixin(Eval!int); <-- int var here
> 
> 
> Basically I need a string mixin inserted into the template before the template parameters are evaluated.

Not enough context; I'm not sure what exactly you want to achieve.

The above can simply be done like this:

   enum source = "TYPE var;";

   mixin template Eval(TYPE) { mixin(source); }

   void main() {
       mixin Eval!int;
       static assert (is(typeof(var) == int));
   }

artur

On 21.7.2013 19:15, Ali Çehreli wrote:
>     string Eval()
>     {
>         string statement = source;
>         auto found = statement.findSkip("TYPE");
>         assert(found);
> 
>         return TYPE.stringof ~ statement;
>     }

Thanks, actually findSplit is what I need, but works like a charm. CTFE rox !


-- 
mk