Idioms you use

[Artur Skawina via Digitalmars-d]

On 10/03/15 15:53, Marco Leise via Digitalmars-d wrote:
> Am Mon, 28 Sep 2015 21:40:43 +0000
> schrieb Freddy <Hexagonalstar64 at gmail.com>:
> 
>> Are any D idioms you use that you like to share?
>> Heres one of mine
>> ---
>> enum ctfe =
>> {
>>      return 0xdead & 0xbad;
>> }();
>> ---
> 
> Yep, using that often, although I try to get my head around
> using functional style one-line expressions where possible to
> avoid the boilerplate.
> 
> static immutable ctfe = {
>     bool[256] result;
>     foreach (i; 0 .. 256)
>         result = isDigit(i);
>     return result;
> }();
> 
> ==>
> 
> static immutable bool[256] ctfe = iota(256).map!isDigit.array;
> 
> ==>
> 
> static ctfe = ctfeArr!( iota(256).map!isDigit );
> 
> enum ctfeArr(alias r)()
> {
> 	// r.length doesn't work as static array size
> 	enum length = r.length;
> 	// immutable doesn't work on this (cannot modify const)
> 	ElementType!(typeof(r))[length] result = r.array;
> 	// Cross fingers here ...
> 	return cast(immutable) result;
> }

==>

   static ctfe = ctfeArr!( iota(256).map!isDigit() );

   immutable typeof(R.front)[R.array().length] ctfeArr(alias R) = R.array();


[`array` is only required because of compiler issues, yes.]

artur