Re: faster "stringification"

2016-12-10 Thread Nicholas Wilson via Digitalmars-d-learn

On Sunday, 11 December 2016 at 02:09:41 UTC, Orut wrote:
D nub here. I have a Python script that I'd like to implement 
in D. For certain parts, the D equivalent was slower than 
Python's. For example,


Python code:

#dummy code
s = ["abc", "fjkd", "L", "qwa", "r", "uw", "tiro", "bc", "sg", 
"k", "jds", "yd"];


for i in range(1000):  # a lot of array to string 
conversions
'-'.join(s)# not assigning this to a variable to 
simplify comparison



D code:

import std.stdio;
import std.array;

void main(string[] args){
string[] s = ["abc", "fjkd", "L", "qwa", "r", "uw", "tiro", 
"bc", "sg", "k", "jds", "yd"];
for(int i; i<10_000_000; i++) s.join("-"); //see Python 
comments


}

Python was 2x faster.

How should I implement this in D?


join performs allocations which is probably the reason for its 
slowness. There is joiner (in std.algorithm.iterations) that 
lazily performs the join, (though in the case of this "benchmark" 
will be cheating because you don't do anything with the result, 
print it to get a more fair comparison) avoiding allocation.


see also appender (in std.array) for fast concatenation.


Re: faster "stringification"

2016-12-10 Thread Stefan Koch via Digitalmars-d-learn

On Sunday, 11 December 2016 at 02:09:41 UTC, Orut wrote:
D nub here. I have a Python script that I'd like to implement 
in D. For certain parts, the D equivalent was slower than 
Python's. For example,


Python code:

#dummy code
s = ["abc", "fjkd", "L", "qwa", "r", "uw", "tiro", "bc", "sg", 
"k", "jds", "yd"];


for i in range(1000):  # a lot of array to string 
conversions
'-'.join(s)# not assigning this to a variable to 
simplify comparison



D code:

import std.stdio;
import std.array;

void main(string[] args){
string[] s = ["abc", "fjkd", "L", "qwa", "r", "uw", "tiro", 
"bc", "sg", "k", "jds", "yd"];
for(int i; i<10_000_000; i++) s.join("-"); //see Python 
comments


}

Python was 2x faster.

How should I implement this in D?


Preallocate a static array for your result.



faster "stringification"

2016-12-10 Thread Orut via Digitalmars-d-learn
D nub here. I have a Python script that I'd like to implement in 
D. For certain parts, the D equivalent was slower than Python's. 
For example,


Python code:

#dummy code
s = ["abc", "fjkd", "L", "qwa", "r", "uw", "tiro", "bc", "sg", 
"k", "jds", "yd"];


for i in range(1000):  # a lot of array to string conversions
'-'.join(s)# not assigning this to a variable to simplify 
comparison



D code:

import std.stdio;
import std.array;

void main(string[] args){
string[] s = ["abc", "fjkd", "L", "qwa", "r", "uw", "tiro", 
"bc", "sg", "k", "jds", "yd"];
for(int i; i<10_000_000; i++) s.join("-"); //see Python 
comments


}

Python was 2x faster.

How should I implement this in D?




Re: Hosting vibe.d on OpenShift

2016-12-10 Thread Gerald via Digitalmars-d-learn

On Saturday, 10 December 2016 at 17:54:58 UTC, aberba wrote:

On Thursday, 8 December 2016 at 20:37:23 UTC, Tiberiu Gal wrote:

On Thursday, 8 December 2016 at 14:03:35 UTC, aberba wrote:
I would like to try vibe.d with mongoDB on OpenShit. I 
managed to do that on Heroku. Do I need a buildpack like 
vibe.d?


Any help will be really appreciated.


I've tried to create a vibe cartridge but cannot because of 
memory limitations.
The easiest way: You should build locally and deploy the 
executable


Aawsh!!


Cartridges are for OpenShift v2 and earlier, I would highly 
recommend trying OpenShift v3 instead. OpenShift v3 switched to 
using Docker (as well as Kubernetes) so if there is a vibe.d 
docker package or you can get it packaged in docker yourself it 
should run in OpenShift just fine.


Note that v3 is in developer preview for Online, however I'd 
suggest using either Red Hat's CDK 
(https://developers.redhat.com/products/cdk/overview/) or 
Minishift (https://github.com/minishift/minishift) as an easy way 
to play around with it.


Re: mkdir; remove; under Windows throw Exception

2016-12-10 Thread unDEFER via Digitalmars-d-learn
On Saturday, 10 December 2016 at 18:30:53 UTC, Adam D. Ruppe 
wrote:

On Saturday, 10 December 2016 at 18:09:43 UTC, unDEFER wrote:

I know, but why it works in Linux by Linux documentation?


Coincidence. That detail is undefined in the D documentation 
which means the implementation is free to do whatever is easier 
for it in a platform-specific manner.


OH, OK. Undocumented behavior is undocumented behavior...


Re: [Semi-OT] I don't want to leave this language!

2016-12-10 Thread Igor Shirkalin via Digitalmars-d-learn

On Monday, 5 December 2016 at 20:25:00 UTC, Ilya Yaroshenko wrote:

Hi e-y-e,

The main problem with D for production is its runtime. GC, 
DRuntime, Phobos is big constraint for real world software 
production.




The almost only thing I do is real world software production 
(basically math and optimized math methods). D with it's GC, 
DRuntime and Phobos makes it what I really like and need for. I 
do my own libs for my own needs. Perhaps some day I will use Mir, 
but I don't care if it is with or without D's standard libs.


Igor Shirkalin.


Re: mkdir; remove; under Windows throw Exception

2016-12-10 Thread Adam D. Ruppe via Digitalmars-d-learn

On Saturday, 10 December 2016 at 18:09:43 UTC, unDEFER wrote:

I know, but why it works in Linux by Linux documentation?


Coincidence. That detail is undefined in the D documentation 
which means the implementation is free to do whatever is easier 
for it in a platform-specific manner.


Re: mkdir; remove; under Windows throw Exception

2016-12-10 Thread unDEFER via Digitalmars-d-learn

On Saturday, 10 December 2016 at 14:10:15 UTC, ag0aep6g wrote:

On 12/10/2016 04:39 AM, unDEFER wrote:

man remove:

remove - remove a file or directory


That's documentation for C, not for D.


I know, but why it works in Linux by Linux documentation?



Re: Separate IP parts

2016-12-10 Thread aberba via Digitalmars-d-learn
On Saturday, 10 December 2016 at 13:25:13 UTC, Nicholas Wilson 
wrote:

On Saturday, 10 December 2016 at 13:21:40 UTC, notna wrote:

On Saturday, 10 December 2016 at 08:03:00 UTC, biozic wrote:

[...]


Well, you know, that's one of the not so great things about 
Dlang... you cannot even trust the provided examples, if there 
are any:


[...]


Those statements need to be inside a function.


I guess that's the reputation complaints here a building up :)


Re: Hosting vibe.d on OpenShift

2016-12-10 Thread aberba via Digitalmars-d-learn

On Thursday, 8 December 2016 at 20:37:23 UTC, Tiberiu Gal wrote:

On Thursday, 8 December 2016 at 14:03:35 UTC, aberba wrote:
I would like to try vibe.d with mongoDB on OpenShit. I managed 
to do that on Heroku. Do I need a buildpack like vibe.d?


Any help will be really appreciated.


I've tried to create a vibe cartridge but cannot because of 
memory limitations.
The easiest way: You should build locally and deploy the 
executable


Aawsh!!


Re: mkdir; remove; under Windows throw Exception

2016-12-10 Thread ag0aep6g via Digitalmars-d-learn

On 12/10/2016 04:39 AM, unDEFER wrote:

man remove:

remove - remove a file or directory


That's documentation for C, not for D.


The function which removes only files named unlink.

The D must guarantee the same behaviour of remove on all OSes.


D has no obligation to follow C in function naming.


Re: Separate IP parts

2016-12-10 Thread Nicholas Wilson via Digitalmars-d-learn

On Saturday, 10 December 2016 at 13:21:40 UTC, notna wrote:

On Saturday, 10 December 2016 at 08:03:00 UTC, biozic wrote:

[...]


Well, you know, that's one of the not so great things about 
Dlang... you cannot even trust the provided examples, if there 
are any:


[...]


Those statements need to be inside a function.


Re: Separate IP parts

2016-12-10 Thread notna via Digitalmars-d-learn

On Saturday, 10 December 2016 at 08:03:00 UTC, biozic wrote:

This would do the same. I wouldn't say it's a trick.

import std.format : formattedRead;
import std.stdio : writefln;

string ipAddr = "192.168.1.54";
int a, b, c, d;
formattedRead(ipAddr, "%d.%d.%d.%d", , , , );
writefln("%s %s %s %s", a, b, c, d);


Well, you know, that's one of the not so great things about 
Dlang... you cannot even trust the provided examples, if there 
are any:


C:\Temp\D>more formattedReadIps.d
import std.format;
string s = "hello!124:34.5";
string a;
int b;
double c;
formattedRead(s, "%s!%s:%s", , , );
assert(a == "hello" && b == 124 && c == 34.5);

C:\Temp\D>dmd -v formattedReadIps.d
binaryC:\D\dmd2\windows\bin\dmd.exe
version   v2.072.1
configC:\D\dmd2\windows\bin\sc.ini
parse formattedReadIps
formattedReadIps.d(6): Error: unexpected ( in declarator
formattedReadIps.d(6): Error: basic type expected, not "%s!%s:%s"
formattedReadIps.d(6): Error: found '"%s!%s:%s"' when expecting 
')'
formattedReadIps.d(6): Error: no identifier for declarator 
formattedRead(s, _error_)
formattedReadIps.d(6): Error: semicolon expected following 
function declaration

formattedReadIps.d(6): Error: declaration expected, not ','
formattedReadIps.d(7): Error: declaration expected, not 'assert'




Re: function is not callable using argument types ()

2016-12-10 Thread Stefan Koch via Digitalmars-d-learn

On Saturday, 10 December 2016 at 08:41:56 UTC, Suliman wrote:

import std.stdio;
import std.concurrency;

void main()
{

void sp(int i)
{
receive((int i)
{
writeln("i: ", i);
});
}

auto r = new Generator!int(
{
foreach(i; 1 .. 10)
yield(i);
});

foreach(e;r)
{
		sp.send(e); //Error: function app.main.sp (int i) is not 
callable using argument types ()

}

}


What I am doing wrong? How "receive" can be named? Is it's 
method or what? Why it's without return type?


Sp is not in global scope but defined in main.
Therefore it does not participate in UFCS.


function is not callable using argument types ()

2016-12-10 Thread Suliman via Digitalmars-d-learn

import std.stdio;
import std.concurrency;

void main()
{

void sp(int i)
{
receive((int i)
{
writeln("i: ", i);
});
}

auto r = new Generator!int(
{
foreach(i; 1 .. 10)
yield(i);
});

foreach(e;r)
{
		sp.send(e); //Error: function app.main.sp (int i) is not 
callable using argument types ()

}

}


What I am doing wrong? How "receive" can be named? Is it's method 
or what? Why it's without return type?







Re: Separate IP parts

2016-12-10 Thread biozic via Digitalmars-d-learn

On Saturday, 10 December 2016 at 03:51:34 UTC, brocolis wrote:

How do I separate IP parts with dlang?

I found this very cool trick, with C++: 
http://stackoverflow.com/a/5328190


std::string ip ="192.168.1.54";
std::stringstream s(ip);
int a,b,c,d; //to store the 4 ints
char ch; //to temporarily store the '.'
s >> a >> ch >> b >> ch >> c >> ch >> d;
std::cout << a << "  " << b << "  " << c << "  "<< d;

I wonder what's the equivalent D code.


This would do the same. I wouldn't say it's a trick.

import std.format : formattedRead;
import std.stdio : writefln;

string ipAddr = "192.168.1.54";
int a, b, c, d;
formattedRead(ipAddr, "%d.%d.%d.%d", , , , );
writefln("%s %s %s %s", a, b, c, d);



Re: staticIota is easy

2016-12-10 Thread Stefan Koch via Digitalmars-d-learn

On Saturday, 10 December 2016 at 01:48:24 UTC, Ali Çehreli wrote:

On 12/09/2016 05:34 PM, Stefan Koch wrote:

On Friday, 9 December 2016 at 18:52:59 UTC, Ali Çehreli wrote:
I thought I needed something like staticIota in a unittest to 
effect
static foreach over a number range and I found one in 
druntime's

implementation:


https://github.com/dlang/druntime/blob/master/src/core/internal/traits.d#L106


(I wonder why that one is implemented in divide-and-conquer 
fashion.

Perhaps due to faster compilation that way?)



Yes it is.
n log n
instead of n^2



Makes sense. I was stopping my counting at n: both looked O(n) 
to me. :)


How about my staticIota()? Is it n^2 inside the compiler?

Ali


it's O(n log n)*((n!)/some_really_large_number)

Because the template-subsystem is it not really build for a abuse 
like AliasSeq.

After a cut-off point the factorial factor will dominate.