D dropped in favour of C# for PSP emulator

[Andrei Alexandrescu]

On 5/17/12 4:00 AM, Peter Alexander wrote:
> On Tuesday, 15 May 2012 at 17:23:28 UTC, Kirill wrote:
>> How about users who don't know what binary search is. binary search is
>> an intuitive concept for people who have good programming experience
>> but assumeSorted(r).contains(x) is more intuitive to higher level users.
>
> If you don't know about binary search, you won't write
> assumeSorted(r).contains(x) you'll just write r.contains(x) because you
> have no idea that binary search exists. Why would you bother typing
> extra characters for a benefit that you are unaware of?
>
> If you do know that binary search exists then the obvious algorithm name
> is binarySearch. If I use .contains to coax a binarySearch then I'm
> relying on a little bit of faith. In what situations does it give a
> binary search?
>
> [1, 2, 3].contains(2); // does the compiler infer that 1, 2, 3 is sorted?

Doesn't compile.

> iota(10).contains(5); // is iota implicitly a sorted range?

Doesn't compile.

> assumeSorted([1, 2, 3]).map!(x => x + 1).contains(3); // does Phobos
> know that the map is order preserving?

Doesn't compile, this would:

assumeSorted([1, 2, 3].map!(x => x + 1)).contains(3)

(which is quite a trick; map figures the input is a random-access range 
and exposes a random-access interface as well. Good luck doing that in 
other languages.)

> assumeSorted([1, 2, 3]).filter!("a & 1").contains(2); // does Phobos
> know that filters always preserve order?

Doesn't compile, and couldn't because filter() cannot preserve random 
access.

> I'd have to read the documentation to find out which of these uses
> binary search. In fact, I'd probably have to read the Phobos source.
>
> If I just used binarySearch then I would be 100% guaranteed that it will
> use a binary search. I don't have to second guess the compiler -- I just
> *know*.

I agree binarySearch is more precise, but I also think it's a minor 
issue not worth the cost of changing at this point. Improving names of 
things in the standard library is a quest that could go forever, make 
everybody happy we're making progress, and achieve no substantial gain.


Andrei