NotNull pointers

[Timon Gehr]

On 09/01/2011 12:26 AM, Simen Kjaeraas wrote:
> On Wed, 31 Aug 2011 23:54:04 +0200, Timon Gehr <timon.gehr at gmx.ch> wrote:
>
>>> [2 * x ; x <- iota(10), log(x), x*x > 4]
>>>
>>> or, in a library:
>>>
>>> compr!q {2 * x ; x <- iota(10), log(x), x*x > 4};
>>>
>>>
>>
>> compr!q{2 * x ; x <- iota(10), log(x), x*x > 4};
>
> The library solution has problems with scope variables.

I know, that is why I have not implemented this yet. Basically it should 
be possible to implicitly pass a whole scope to a template, or at least, 
to have local templates.

> Example:
>
> auto foo(Range)(int n, Range r) {
> return compr!q{x * n; x <- arr, log(x), x*x > 4};
> }

Workaround:
auto foo(Range)(int n, Range r) {
     mixin Compr!q{x * n ; x <- arr, log(x), x*x > 4};
     return compr;
}


>
> More importantly, IMO, is that the notation does not clearly
> mark what is what. is that interpreted (iota(10), log(x))
> or (log(x), x*x > 4)?
>

It actually does. The comma is a mere separator, and imho it looks very 
clean. It is just like the set builder syntax you like. (it even has the 
curly brackets!)