Re: cannot sort an array of char
IK For example, isRandomAccessRange[0] states the problem: IK - IK Although char[] and wchar[] (as well as their qualified IK versions including string and wstring) are arrays, IK isRandomAccessRange yields false for them because they use IK variable-length encodings (UTF-8 and UTF-16 respectively). IK These types are bidirectional ranges only. IK - IK but does not offer a solution. If (when) byCodeUnit does IK really provide a random-access range, it would be desirable to IK have it linked where the problem is stated. IK IK [0] http://dlang.org/phobos/std_range.html#.isRandomAccessRange MS I agree. But how should it be implemented? We would have to MS modify algorithms that require an RA range to also accept MS char[], but then print an error message with the suggestion to MS use byCodeUnit. I think that's not practicable. Any better MS ideas? I meant just mentioning a workaround (byCodeUnit or representation) in the documentation, not in a compiler error. But the latter option does have some sense, too.
Re: cannot sort an array of char
IK Why is char [] so special that it can't be sorted? SS Because sort works on ranges, and std.range has the view that SS char[] is a range of dchar without random access. Nevermind SS what the compiler thinks :) SS SS I believe you can get what you want with SS std.string.representation: SS SS import std.string; SS SS sort(c.representation); Thank you for showing a library way to do that. I ended up with using a cast, like sort (cast (ubyte []) c). And this looks like a safe way to do the same. Now, std.utf's byCodeUnit and std.string's representation seem like duplicate functionality, albeit with different input and output types (and bugs :) ).
Re: cannot sort an array of char
On 11/11/14 6:07 AM, Ivan Kazmenko wrote: IK Why is char [] so special that it can't be sorted? SS Because sort works on ranges, and std.range has the view that SS char[] is a range of dchar without random access. Nevermind SS what the compiler thinks :) SS SS I believe you can get what you want with SS std.string.representation: SS SS import std.string; SS SS sort(c.representation); Thank you for showing a library way to do that. I ended up with using a cast, like sort (cast (ubyte []) c). And this looks like a safe way to do the same. It's safe but be careful. For instance, if c becomes an immutable(char)[] or const(char)[], then you will have undefined behavior. If you use the representation, it will properly reject this behavior. Now, std.utf's byCodeUnit and std.string's representation seem like duplicate functionality, albeit with different input and output types (and bugs :) ). No, byCodeUnit is not an array, it's a range of char. They solve different problems, and mean different things. Note, byCodeUnit should work for sort, I'm surprised it doesn't. -Steve
Re: cannot sort an array of char
On Tuesday, 11 November 2014 at 13:20:53 UTC, Steven Schveighoffer wrote: On 11/11/14 6:07 AM, Ivan Kazmenko wrote: IK Why is char [] so special that it can't be sorted? SS Because sort works on ranges, and std.range has the view that SS char[] is a range of dchar without random access. Nevermind SS what the compiler thinks :) SS SS I believe you can get what you want with SS std.string.representation: SS SS import std.string; SS SS sort(c.representation); Thank you for showing a library way to do that. I ended up with using a cast, like sort (cast (ubyte []) c). And this looks like a safe way to do the same. It's safe but be careful. For instance, if c becomes an immutable(char)[] or const(char)[], then you will have undefined behavior. If you use the representation, it will properly reject this behavior. Now, std.utf's byCodeUnit and std.string's representation seem like duplicate functionality, albeit with different input and output types (and bugs :) ). No, byCodeUnit is not an array, it's a range of char. They solve different problems, and mean different things. Note, byCodeUnit should work for sort, I'm surprised it doesn't. That's what he meant by bugs :-P But it's been fixed already, thanks to H.S. Teoh.
Re: cannot sort an array of char
On Wednesday, 5 November 2014 at 13:34:05 UTC, Marc Schütz wrote:
On Wednesday, 5 November 2014 at 12:54:03 UTC, Ivan Kazmenko
wrote:
Hi!
This gives an error (cannot deduce template function from
argument types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
For example, if I know the array contains only ASCII
characters, sorting it sounds no different to sorting an int
[].
Hmm... this doesn't work either:
import std.algorithm;
import std.utf;
void main () {
char [] c;
sort (c.byCodeUnit);
}
But IMO it should.
So, you imply that to use a char array as a RandomAccessRange, I
have to use byCodeUnit? (and it should work, but doesn't?)
Fine, but how does one learn that except by asking here?
Googling did not produce meaningful results for me.
For example, isRandomAccessRange[0] states the problem:
-
Although char[] and wchar[] (as well as their qualified versions
including string and wstring) are arrays, isRandomAccessRange
yields false for them because they use variable-length encodings
(UTF-8 and UTF-16 respectively). These types are bidirectional
ranges only.
-
but does not offer a solution. If (when) byCodeUnit does really
provide a random-access range, it would be desirable to have it
linked where the problem is stated.
[0] http://dlang.org/phobos/std_range.html#.isRandomAccessRange
Re: cannot sort an array of char
On Thursday, 6 November 2014 at 10:52:32 UTC, Ivan Kazmenko wrote:
On Wednesday, 5 November 2014 at 13:34:05 UTC, Marc Schütz
wrote:
On Wednesday, 5 November 2014 at 12:54:03 UTC, Ivan Kazmenko
wrote:
Hi!
This gives an error (cannot deduce template function from
argument types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
For example, if I know the array contains only ASCII
characters, sorting it sounds no different to sorting an int
[].
Hmm... this doesn't work either:
import std.algorithm;
import std.utf;
void main () {
char [] c;
sort (c.byCodeUnit);
}
But IMO it should.
So, you imply that to use a char array as a RandomAccessRange,
I have to use byCodeUnit? (and it should work, but doesn't?)
Yes. H.S. Teoh has already submitted a PR to fix it.
Fine, but how does one learn that except by asking here?
Googling did not produce meaningful results for me.
For example, isRandomAccessRange[0] states the problem:
-
Although char[] and wchar[] (as well as their qualified
versions including string and wstring) are arrays,
isRandomAccessRange yields false for them because they use
variable-length encodings (UTF-8 and UTF-16 respectively).
These types are bidirectional ranges only.
-
but does not offer a solution. If (when) byCodeUnit does
really provide a random-access range, it would be desirable to
have it linked where the problem is stated.
[0] http://dlang.org/phobos/std_range.html#.isRandomAccessRange
I agree. But how should it be implemented? We would have to
modify algorithms that require an RA range to also accept char[],
but then print an error message with the suggestion to use
byCodeUnit. I think that's not practicable. Any better ideas?
Re: cannot sort an array of char
On 11/5/14 7:54 AM, Ivan Kazmenko wrote:
Hi!
This gives an error (cannot deduce template function from argument types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
Because sort works on ranges, and std.range has the view that char[] is
a range of dchar without random access. Nevermind what the compiler
thinks :)
I believe you can get what you want with std.string.representation:
import std.string;
sort(c.representation);
-Steve
cannot sort an array of char
Hi!
This gives an error (cannot deduce template function from
argument types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
For example, if I know the array contains only ASCII characters,
sorting it sounds no different to sorting an int [].
Ivan Kazmenko.
Re: cannot sort an array of char
On Wednesday, 5 November 2014 at 12:54:03 UTC, Ivan Kazmenko
wrote:
Hi!
This gives an error (cannot deduce template function from
argument types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
For example, if I know the array contains only ASCII
characters, sorting it sounds no different to sorting an int
[].
Hmm... this doesn't work either:
import std.algorithm;
import std.utf;
void main () {
char [] c;
sort (c.byCodeUnit);
}
But IMO it should.
Re: cannot sort an array of char
On Wednesday, 5 November 2014 at 13:34:05 UTC, Marc Schütz wrote:
On Wednesday, 5 November 2014 at 12:54:03 UTC, Ivan Kazmenko
wrote:
Hi!
This gives an error (cannot deduce template function from
argument types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
For example, if I know the array contains only ASCII
characters, sorting it sounds no different to sorting an int
[].
Hmm... this doesn't work either:
import std.algorithm;
import std.utf;
void main () {
char [] c;
sort (c.byCodeUnit);
}
But IMO it should.
https://issues.dlang.org/show_bug.cgi?id=13689
Re: cannot sort an array of char
On 11/05/2014 05:44 AM, Marc Schütz schue...@gmx.net wrote:
On Wednesday, 5 November 2014 at 13:34:05 UTC, Marc Schütz wrote:
On Wednesday, 5 November 2014 at 12:54:03 UTC, Ivan Kazmenko wrote:
Hi!
This gives an error (cannot deduce template function from argument
types):
-
import std.algorithm;
void main () {
char [] c;
sort (c);
}
-
Why is char [] so special that it can't be sorted?
For example, if I know the array contains only ASCII characters,
sorting it sounds no different to sorting an int [].
Hmm... this doesn't work either:
import std.algorithm;
import std.utf;
void main () {
char [] c;
sort (c.byCodeUnit);
}
But IMO it should.
https://issues.dlang.org/show_bug.cgi?id=13689
It can't be a RandomAccessRange because it cannot satisfy random access
at O(1) time.
Ali
Re: cannot sort an array of char
On 11/05/2014 10:01 AM, Ali Çehreli wrote: sort (c.byCodeUnit); } But IMO it should. https://issues.dlang.org/show_bug.cgi?id=13689 It can't be a RandomAccessRange because it cannot satisfy random access at O(1) time. Sorry, I misunderstood (again): code unit is random-access, code point is not. Ali P.S. I would like to have a word with the Unicode people who settled on the terms code unit and code point. Every time I come across one of those, I have to think at least 5 seconds to fool myself to think that I understood correctly which one was meant. :p
