Confused by struct constructors

[Philippe Sigaud]

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:

arr[0]  = T(args[0..n]);


Maybe you could also use S.tupleof.length to get the number of fields in S
(or maybe there is a __traits which gives this) and avoid the recursion in
initArray:


void fillArr( T, U... )( ref T[] arr, U args ) {
 arr[0] =  T(args[0..T.tupleof.length]) ;
 static if ( U.length > T.tupleof.length ) {
   fillArr( arr[ 1..$ ], args[ T.tupleof.length..$ ] );
 }
}

T[] initArray( T, U... )( U args )
    if ( U.length > 0
    && (is(typeof( T( args[ 0..T.tupleof.length ] ) ) ) )
    && ( U.length % T.tupleof.length == 0 ))
{
   T[] result = new T[ U.length / T.tupleof.length ];         // Create an
array
   fillArr( result, args );              // and fill it.
   return result;
}

Philippe
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