On Wed, 14 May 2014 05:13:42 -0400, Jonathan M Davis via
Digitalmars-d-learn <digitalmars-d-learn@puremagic.com> wrote:
On Wed, 14 May 2014 08:27:45 +0000
monarch_dodra via Digitalmars-d-learn
<digitalmars-d-learn@puremagic.com> wrote:
On Monday, 12 May 2014 at 18:44:22 UTC, Jonathan M Davis via
Digitalmars-d-learn wrote:
> Sure, you can cast char[] to ubyte[] and sort that if you know
> that the array
> only holds pure ASCII. In fact, you can use
> std.string.representation to do it
> - e.g.
>
> auto ascii = str.representation;
>
> and if str were mutable, then you could sort it. But that will
> only work if
> the string only contains ASCII characters. Regardless, he
> wanted to know why
> he couldn't sort char[], and I explained why - all strings are
> treated as
> ranges of dchar, making it so that if their element type is
> char or wchar, so
> they're not random access and thus can't be sorted.
Arguably, a smart enough implementation should know how to sort a
"char[]", while still preserving codepoint integrity.
I don't think that that can be done at the same algorithmic complexity
though.
So, I don't know if that would be acceptable or not from the standpoint
of
std.algorithm.sort. But even if it's a good idea, someone would have to
special case sort for char[], and no one has done that.
I think it can be done at O(nlgn) complexity, but you must allocate a
block of scratch space to do the sorting. You can't do it in-place because
swapping isn't available.
Might as well convert to dchar and back explicitly.
Merge sort may allow more promising speedups, but I still think you will
need to allocate extra space.
As a matter of fact, the built in "sort" property does it.
void main()
{
char[] s = "éöeèûà".dup;
s.sort;
writeln(s);
}
//prints:
eàèéöû
I'm surprised. I thought that one of Bearophile's favorite complaints
was that
it didn't sort unicode properly (and hence one of the reasons that it
should
be removed). Regardless, I do think that it should be removed.
I can't believe this worked. I want to say that it's a freak accident for
that set of characters. Looking in druntime, I don't see where the special
case is.
-Steve
