What are the unused but useful feature you know in D?

[rikki cattermole]

On 04/11/2017 6:13 PM, bauss wrote:
> On Saturday, 4 November 2017 at 13:27:29 UTC, rikki cattermole wrote:
>> On 04/11/2017 2:14 PM, jmh530 wrote:
>>> [...]
>>
>> Okay so:
>>
>> A signature when it is initiated is aware of the implementation it is 
>> referencing. Allowing it to change how it behaves for compatibility 
>> reasons.
>>
>> An interface is designed so that a class/interface must know of the 
>> interface to inherit from.
>>
>> While signatures can and probably will inherit from others, this is 
>> not how it is used unlike with interfaces. Because this is a massive 
>> change in how we view them and their usage, extending interfaces is 
>> not appropriate. Luckily an already existing concept exists in the 
>> literature which does solve most of the goals and that is signatures 
>> from the ML family.
>>
>> I will make a mental note to rewrite that section.
> 
> It reminds a lot of traits in Rust.
> 
> https://doc.rust-lang.org/1.8.0/book/traits.html

Rust traits are a variant of ML's signature. Only they decided to add a 
whole new concept which is 'impl' to it.

While it is a nice idea, it would be a pain to use in real life and 
defeat the purpose of a signature. Which is to act as more of a 
'concept' abstraction to other items.

Because we have such powerful meta-programming features I see no reason 
to separate out the two. We can do it all in one which makes it nice and 
consistent between all the different implementations for a signature 
type. So far its starting to feel right at home against our structs and 
class support, I think.