D component programming is a joke (Was: Re: Component programming)

[Andre Artus]

On Saturday, 3 August 2013 at 13:46:38 UTC, David Nadlinger wrote:
> On Saturday, 3 August 2013 at 13:35:56 UTC, Andre Artus wrote:
>> import std.stdio;
>> import std.algorithm;
>> void main()
>> {
>>  auto values = [ 1, 2, 3, 4, 5 ];
>>  writeln(values
>>    .map!(a => a * 10)
>>    .map!(a => a / 3)
>>    .filter!(a => !(a % 2)));
>> }
>>
>> As stated this implies 3 separate traversals of the list (or 
>> array to be specific) which is what a naïve implementation 
>> would do.
>
> In this example, no, as all involved ranges are evaluated 
> lazily. (I see your general point, though.)
>
> David

I probably could have worded it better: I did not intend to imply 
that D follows the naïve implementation suggested. What I meant 
is that, on the face of it, given typical textbook 
implementations of map and filter you would be iterating 3 
separate times. To be clear I don't know of any serious 
implementations of these algorithms that do not address this in 
some way.