What is your favorite D feature?

[Anonymouse via Digitalmars-d]

On Thursday, 22 June 2017 at 00:48:25 UTC, Seb wrote:
> Hi,
>
> I am currently trying to modernize the D code example roulette 
> on the dlang.org front page [1]. Hence, I would love to hear 
> about your favorite feature(s) in D.
> Ideas:
> - favorite language construct
> - favorite code sample
> - "only possible in D"
>
> Before you ask, yes - I want to add a couple of cool examples 
> to dlang.org (and yep the roulette rotation is currently broken 
> [2]).
>
> [1] 
> https://github.com/dlang/dlang.org/pulls?q=is%3Apr+is%3Aopen+label%3A%22Frontpage+example%22
> [2] https://github.com/dlang/dlang.org/pull/1757

Fairly specific, but foreach (member; someStruct.tupleof).

Part of my work on my IRC bot has been to serialise structs into 
configuration files (since std.json was *non-trivial* to deal 
with), and foreaching a someStruct.tupleof or a 
__traits(allMembers, symbol) allows for really, really 
interesting stuff.