Why not extend array operations to full Fortran90 power ?

[Xinok]

On 11/16/2011 4:48 PM, Simen Kjærås wrote:
> On Wed, 16 Nov 2011 22:31:31 +0100, Xinok <xinok at live.com> wrote:
>
>> On 11/16/2011 2:08 PM, Joachim Wuttke <j.wuttke at fz-juelich.de> wrote:
>>> Compare
>>>
>>> (1) Y[] = X[]*X[];
>>> (2) Y[] = sin( X[] );
>>>
>>> With gdc 4.4.6,
>>> (1) compiles and executes as I expected, whereas
>>> (2) is not allowed (fails at compile time).
>>> Why?
>>>
>>> The semantics of (2) is unambiguous,
>>> and it works perfectly well in Fortran90.
>>> Allowing (2) would make D really attractive
>>> for formula-heavy mathematical work.
>>>
>>> - Joachim
>>>
>> I think vector operations are designed to avoid turning them into
>> loops. In (2), this would require several calls to sin().
>
> Really? How would you do Y[] = X[] * X[] without a loop?

That's not what I meant by it. Perhaps an example is in order:

void main(){
	int rand(){
		rndGen.popFront();
		return rndGen.front;
	}
	
	int[5] a;
	int[5] b = [1000, 2000, 3000, 4000, 5000];
	a[] = b[] + (rand() % 1000);
	writeln(a);
}

This is the result:
[1299, 2299, 3299, 4299, 5299]

It adds the same random value to each element, meaning it only calls 
rand() once. D doesn't treat vector operations like loops.