Impressed

[Brad Anderson]

On Thu, Jul 26, 2012 at 7:56 PM, Stuart <stugol at gmx.com> wrote:

> On Friday, 27 July 2012 at 00:10:31 UTC, Brad Anderson wrote:
>
>> D uses ranges instead of iterators. You can read more about them here:
>> http://ddili.org/ders/d.en/**ranges.html<http://ddili.org/ders/d.en/ranges.html>
>>
>> I find ranges to be a vast improvement over iterators personally (I use
>> iterators extensively in C++ for my job and lament not having ranges
>> regularly).
>>
>>
>>  On Friday, 27 July 2012 at 00:17:21 UTC, H. S. Teoh wrote:
>
>> D has something far superior: ranges.
>>
>>         http://www.informit.com/**articles/printerfriendly.aspx?**
>> p=1407357&rll=1<http://www.informit.com/articles/printerfriendly.aspx?p=1407357&rll=1>
>>
>> Even better, they are completely implemented in the library. No
>> unnecessary language bloat just to support them.
>>
>
> I'm not very well up on ranges. I understand the general [1 ... 6] type of
> ranges, but I really don't see how custom range functions could be as
> useful as the Yield support in VB.NET. I mean, here's an example of an
> iterator in VB.NET:
>
>    Public Function InfiniteSequence(StartValue As Int32, Step As Int32) As
> IEnumerable(Of Int32)
>       Do
>          Yield StartValue
>          StartValue += Step
>       Loop
>    End Function
>
> Usage:
>
>    For Each N in InfiniteSequence(2, 2)
>       ... do something with this sequence of even numbers ...
>    Next
>
> Notice how this function is written like a synchronous loop, yet yields a
> lazy-initialised infinite sequence of numbers. Granted, it's not a
> particularly useful example, but trust me: Iterators and Yield in .NET is
> *really* damn useful. I would go so far as to say it was one of the
> language's best features.
>
> I may be wrong, but it looks like I'd have to code a new class - not to
> mention several specific functions and some kind of state variable - just
> to simulate this functionality in D. Can anyone clarify this for me?
>

D equivalent: iota(0, int.max, 2).map!(a => /* do something with even
numbers */)();
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