Confused by struct constructors

[Simen kjaeraas]

On Sat, 23 Jan 2010 18:09:26 +0100, Philippe Sigaud  
<philippe.sigaud at gmail.com> wrote:

> On Sat, Jan 23, 2010 at 14:44, Simen kjaeraas  
> <simen.kjaras at gmail.com>wrote:
>
>> In attempting to create a function to initialize any array of structs  
>> in a
>> simple manner, I created this code:
>>
>> void fillArr( uint n, T, U... )( ref T[] arr, U args ) {
>>  arr[0] = T( U[0..n] );
>>  static if ( U.length > n ) {
>>    fillArr!( n )( arr[ 1..$ ], args[ n..$ ] );
>>  }
>> }
>>
>
> U is a type . U[0..n] is also a type. You should write:

Thank you! Darn, I should have been able to see that.

> Maybe you could also use S.tupleof.length to get the number of fields in  
> S

Yeah, I could. However, S might use a different constructor, taking a
different number of arguments.

As for bearophile's concerns:
   struct simpleTuple( T... ) {
     T payload;
   }

   simpleTuple!( T ) ຕ( T... )( T args ) {
     return simpleTuple!( args );
   }

   T[] initArray( T, U... )( U args ) if ( is( typeof( T( args[0].tupleof )  
) ) && allSame!( U ) ) {
     T[] result = new T[ U.length ];
     foreach ( i, arg; args ) {
       result[ i ] = T( arg.tupleof );
     }
     return result;
   }

   struct S {
     int n;
     string s;
   }

   auto s = initArray!( S )( ຕ( 1, "a" ), ຕ( 2, "b" ), ຕ( 3, "c" ) );

If ຕ is too hard to type, choose another short name.

-- 
Simen