Re: Auto keyword with const variable
On Wednesday, 24 July 2013 at 11:26:32 UTC, Mike Parker wrote: This is the exact behavior I would expect. I think of auto as this variable is going to be the same type as that variable. Since in is const int, then j also is going to be const int. If you want to copy n into a nonconst variable, you have to cast away the const. int j = cast( int )n; auto j = cast( int )n; Casting is always an extreme measure, one that should be avoided in mundane code as much as possible. Despite the fact `auto` behaves as it should, this really highlights lack of `mutable` attribute in language.
Re: Build / Package system
On Wednesday, 30 May 2012 at 08:13:34 UTC, Sputnik wrote: There is a build and/or package managment system for D2 that is working? I googled, and I only can find things like dsss or cmaked that don't get updated from a long time ago. I really need to manage to get a project to compile in Windows and Linux. Actually the code not have any OS dependence, so the real diferences in each OS are the linking to gtkd and how and where install the project. Actually I'm using a makfile in Linux that works well, but I can't use it in windows for thing like pkg-config. CMakeD is actually just a bunch of CMake modules and very lightweight, it wouldn't be surprising if it still worked or required more than a few minor changes. I've decided today to migrate my project from C++ to D after being annoyed by the lack of conditional evaluation of code in C++ and the opposition of the core designers of C++ to static if, so I will report later if CMakeD is still useable.
Interesting line in the recent Dr Dobbs article about profiling?
I've just read the article over at Dr Dobbs by Walter http://www.drdobbs.com/cpp/increasing-compiler-speed-by-over-75/240158941 and this line caught my eye: Even if you know your code well, you're likely wrong about where the performance bottlenecks are. Use a profiler. If you haven't used one on your codebase in a while, it's highly likely there's a bottleneck in there that's fixable with just a few lines of code. What profilers do you use with D especially for Linux and Mac? I've been compiling with -profile and trying to grok the output.
Re: Interesting line in the recent Dr Dobbs article about profiling?
On Thu, Jul 25, 2013 at 08:15:42PM +0200, Gary Willoughby wrote: I've just read the article over at Dr Dobbs by Walter http://www.drdobbs.com/cpp/increasing-compiler-speed-by-over-75/240158941 and this line caught my eye: Even if you know your code well, you're likely wrong about where the performance bottlenecks are. Use a profiler. If you haven't used one on your codebase in a while, it's highly likely there's a bottleneck in there that's fixable with just a few lines of code. I can personally testify to the truth of this statement. All too often, too much time is spent optimizing parts of code that are actually irrelevant to the performance of the program, because the bottleneck lies elsewhere, often in an unexpected place. (Not to mention that such premature optimization makes your code harder to write, harder to read, harder to maintain, and therefore more prone to bugs.) I remember at least one instance in which a profiler immediately revealed an fprintf (this was C/C++ code, back in the day) where it shouldn't be, the removal of which instantly improved performance by at least 30%, probably more. What profilers do you use with D especially for Linux and Mac? I've been compiling with -profile and trying to grok the output. I use gdc with gprof, usually. I've only tried dmd -profile a few times. T -- I think Debian's doing something wrong, `apt-get install pesticide', doesn't seem to remove the bugs on my system! -- Mike Dresser
Re: A little of coordination for Rosettacode
This D entry uses Tango, but it should also show a version for Phobos: http://rosettacode.org/wiki/Rosetta_Code/Count_examples#D Bye, bearophile
Re: A little of coordination for Rosettacode
This D entry uses Tango, but it should also show a version for
Phobos:
http://rosettacode.org/wiki/Rosetta_Code/Count_examples#D
Two versions
The Mathematica solution is short:
TaskList = Flatten[
Import[http://rosettacode.org/wiki/Category:Programming_Tasks;,
Data][[1, 1]]];
Print[Task \, StringReplace[#, _ - ], \ has ,
Length@Select[Import[http://rosettacode.org/wiki/; #,
Data][[1,2]],
StringFreeQ[#, __ ~~ Programming Task | __ ~~ Omit] ],
example(s)]
~Map~ StringReplace[TaskList, - _]
This Perl solution is compact:
use v5.10;
use Mojo::UserAgent;
my $site = http://rosettacode.org;;
my $list_url =
/mw/api.php?action=querylist=categorymemberscmtitle=Category:Programming_Taskscmlimit=500format=xml;
my $ua = Mojo::UserAgent-new;
$ua-get($site$list_url)-res-dom-find('cm')-each(sub {
(my $slug = $_-{title}) =~ tr/ /_/;
my $count =
$ua-get($site/wiki/$slug)-res-dom-find(#toc
.toclevel-1)-size;
say $_-{title}: $count examples;
});
The F# solution performs downloads concurrently and it's said to
be fast:
#r System.Xml.Linq.dll
let uri1 =
http://www.rosettacode.org/w/api.php?action=querylist=categorymemberscmtitle=Category:Programming_Taskscmlimit=500format=xml;
let uri2 task = sprintf
http://www.rosettacode.org/w/index.php?title=%saction=raw; task
[|for xml in (System.Xml.Linq.XDocument.Load
uri1).Root.Descendants() do
for attrib in xml.Attributes() do
if attrib.Name.LocalName = title then
yield async {
let uri = uri2 (attrib.Value.Replace( , _) |
System.Web.HttpUtility.UrlEncode)
use client = new System.Net.WebClient()
let! html = client.AsyncDownloadString(System.Uri uri)
let sols' = html.Split([|{{header||],
System.StringSplitOptions.None).Length - 1
lock stdout (fun () - printfn %s: %d examples
attrib.Value sols')
return sols' }|]
| Async.Parallel
| Async.RunSynchronously
| fun xs - printfn Total: %d examples (Seq.sum xs)
Bye,
bearophile
Copying copy?
Range-based functions see strings and char[] to arrays of dchar,
but is that behavour good for std.algorithm.copy too?
I find this a bit silly:
import std.algorithm: copy;
void main() {
char[5] arr1 = hello, arr2;
arr1[].copy(arr2[]); // Error.
dchar[arr1.length] arr3;
arr1[].copy(arr3[]); // OK.
}
What do you think?
Bye,
bearophile
Should I Use std.ascii.isWhite or std.uni.isWhite?
I'm confused about which isWhite function I should use. Aren't all chars in D (char, wchar, dchar) unicode characters? Should I always use std.uni.isWhite, unless I'm working with bytes and byte arrays? The documentation doesn't give me much to go on, beside All of the functions in std.ascii accept unicode characters but effectively ignore them. All isX functions return false for unicode characters, and all toX functions do nothing to unicode characters.
Re: Should I Use std.ascii.isWhite or std.uni.isWhite?
On Friday, July 26, 2013 06:09:39 Meta wrote: I'm confused about which isWhite function I should use. Aren't all chars in D (char, wchar, dchar) unicode characters? Should I always use std.uni.isWhite, unless I'm working with bytes and byte arrays? The documentation doesn't give me much to go on, beside All of the functions in std.ascii accept unicode characters but effectively ignore them. All isX functions return false for unicode characters, and all toX functions do nothing to unicode characters. Unicode contains ASCII, but very few Unicode characters are ASCII, because there just aren't very many ASCII characters and there and a _ton_ of Unicode characters. The std.ascii functions return true for certain sets of ASCII characters and false for everything else. The std.uni functions return true for many Unicode characters as well. You wouldn't normally use std.ascii if you're operating on non-ASCII Unicode characters, but it ignores them if it does run into them. std.ascii.isWhite only cares about ASCII whitespace, which the documentation explicitly lists as the space, tab, vertical tab, form feed, carriage return, and linefeed characters. Those characters will return true. All other characters will return false. std.uni.isWhite returns true for all of the characters that std.ascii.isWhite does plus a whole bunch of other non-ASCII characters that the Unicode standard considers to be whitespace. Which function you use depends on what you're trying to do. - Jonathan M Davis
Re: Copying copy?
On 07/25/2013 04:55 PM, bearophile wrote:
Range-based functions see strings and char[] to arrays of dchar, but is
that behavour good for std.algorithm.copy too?
I find this a bit silly:
import std.algorithm: copy;
void main() {
char[5] arr1 = hello, arr2;
arr1[].copy(arr2[]); // Error.
dchar[arr1.length] arr3;
arr1[].copy(arr3[]); // OK.
}
What do you think?
Bye,
bearophile
I agree. I would expect copy to maintain the same type.
Ali
Re: Should I Use std.ascii.isWhite or std.uni.isWhite?
On Friday, 26 July 2013 at 04:09:46 UTC, Meta wrote:
I'm confused about which isWhite function I should use. Aren't
all chars in D (char, wchar, dchar) unicode characters?
They are.
Should I always use std.uni.isWhite, unless I'm working with
bytes and byte arrays?
No, char vs byte isn't necessarily a thing here.
The documentation doesn't give me much to go on, beside All of
the functions in std.ascii accept unicode characters but
effectively ignore them. All isX functions return false for
unicode characters, and all toX functions do nothing to unicode
characters.
You should use std.uni.isWhite unless you want to match only
ASCII white space.
That could be the case when ...
* You have data that is not in Unicode, but some other superset
of ASCII. Then you shouldn't use std.uni.isWhite, of course.
std.ascii.isWhite might be fine. In this case, you'd actually use
u{byte,short,int} instead of {,w,d}char.
* You're dealing with a grammar where ASCII white space is a
thing, while Unicode white space is not.
* There's really only ASCII white space in your data, and you
want every bit of speed, and you've verified that
std.ascii.isWhite is indeed faster than std.uni.isWhite.
