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
