NotNull pointers

[Simen Kjaeraas]

On Wed, 31 Aug 2011 21:16:37 +0200, bearophile <bearophileHUGS at lycos.com>  
wrote:

> Simen Kjaeraas:
>
>> I feel it is too much a departure from the style otherwise present in D.
>
> This is why I have shown my original syntax with [foreach() if()].
>
>
>> It is important not only that the syntax is good in and of itself,
>> but also in the context of D.
>
> The syntax you have shown is noisy and hard to read.
> Array/seq comps are all (or most) a matter of syntax sugar. So if their  
> syntax is bad, they miss their main point by a mile.

And this is where we disagree. I think the syntax is pretty good, and that  
the
pythonesque syntax sticks out like a sore thumb. Instead of conflating the
concepts of filter, map and source data, I aimed for a solution that is  
familiar
to those accustomed to D, with clear distinctions and the benefits that  
brings.

My design is meant to be somewhat similar to for-loops, with the
semicolon-separated expressions, and to set builder notation. I kinda wish  
'in'
was used in foreach loops (foreach(x in foo){}), as that would be a  
perfect fit
for the <= in the proposed syntax:

My notation:
     [2 * x; x in iota(10); x*x > 4]

Set builder notation:
     {2 · x | x ∈ ℕ, x² > 4}

Personally, I find set builder notation to be very clear and  
understandable, and
thus worth striving to imitate. In D however, the curly brackets and comma
operator already have other meanings that we should try not to interfere  
with.

-- 
   Simen