Template function : use the array's one !

[John C]

TSalm Wrote:

> Hello,
> 
> I'm searching to have a generic comparator function.
> 
> I done this :
> 
> /* ------------ CODE -------------------- */
> import tango.io.Stdout;
> 
> /***
>   * Not for arrays
>   ***/
> int compare(T)(T o1,T o2)
> {
>    static if  ( is( T  bar == class )  || is(  T bar == struct )  )
>      return o1.opCmp(o2);
> 
>    else
>      return o2 - o1;
> }
> 
> /***
>   * For arrays
>   ***/
> int compare(T:T[])(T[] o1,T[] o2)

Change this line to:
  int compare(T:T[])(T o1, T o2)

> {
>    size_t minLength = ( o1.length<o2.length ? o1.length : o2.length) ;
> 
>    for (size_t i=0;i<minLength;i++)
>    {
>      int result = compare(o1[i],o2[i]);
> 
>      if (result != 0)
>        return result;
>    }
> 
>    return o2.length - o1.length ;
> 
> }
> 
> /***
>   * Test
>   ***/
> void main()
> {
>    byte[] a = [10,12,13];
>    byte[] b = [15,16,17];
>    Stdout( compare(a,b) ).newline ;
> }
> /* ------------ END CODE ---------------- */
> 
> 
> 
> But this code return a compilation error :
> test_cmp.d(12): Error: cannot implicitly convert expression (o2 - o1) of  
> type byte[] to int
> test_cmp.d(41): template instance test_cmp.compare!(byte[]) error  
> instantiating
> 
> It seems it's the first compare function (without array in parameter)  
> which is hook.
> 
> How can I declare this compare function to use specific code to compare  
> arrays ?
> Thanks in advance,
> TSalm