Template specialization

[Bill Baxter]

Derek Parnell wrote:
> On Tue, 10 Apr 2007 19:51:36 +0900, Bill Baxter wrote:
> 
>> Derek Parnell wrote:
>>> What is the point of specialization if the compiler can't tell the
>>> difference between data types? I expected that the point of using templates
>>> is to make generic programming simpler.
>> The way I've understood it is that specialization just doesn't work with 
>> IFTI...
>> ... Use 'static if' checks 
>> inside the template if you want to have both IFTI and specialization. 
> 
> Ok, I've tried all the reasonable ways to code this but the magic syntax to
> do it evades my attempts. This whole area of compile-time capabilities is
> very poorly documented.
> 
> Anyway, below is the code I think should work, because it says exactly what
> I want the compiler to know. Namely, if the type (T) used in the code is
> and "int" then do the 'int'-stuff, etc ...
> 
>  template fill_data(T)
>  {
>     void fill_data(char[] raw_data, out T t)
>     {
>         static if (T == int) // LINE 42
>         {
>             t = makeInt( raw_data );
>         }
>         else
>         static if (T == float)
>         {
>             t = toFloat( raw_data );
>         }
>         else
>         {
>             fscopy(t, raw_data);
>         }
>     }
>  } 
> 
> but this gives me messages that do not make sense at all to me ...
> 
>  test2.d(42): found ')' when expecting '.' following 'int'
>  test2.d(43): found '{' when expecting identifier following 'int.'
>  test2.d(44): found 't' when expecting ')'
>  test2.d(44): found '=' instead of statement
>  test2.d(46): Declaration expected, not 'else'
>  test2.d(51): Declaration expected, not 'else'
>  test2.d(54): unrecognized declaration
> 
> Can someone please show me the bleeding obvious correct syntax to use.
> 

You need some is's there like
     static if (is(T==int))