To write such an expressive code D

[Vladimir Panteleev via Digitalmars-d-learn]

On Tuesday, 10 February 2015 at 04:17:48 UTC, Dennis Ritchie 
wrote:
> I just need that code was only used features of the language 
> without using library functions. You may only use the function 
> sin().

Why is that?

Although D has a lot of language features, D tries to push 
functionality into the library as often as possible. This is 
better than having language features for everything, because you 
can then reimplement, tweak or replace said features by simply 
writing D code.