Re: wrapSocket for socket_t? As wrapFile for FILE*
On Sunday, 14 February 2016 at 08:19:16 UTC, Ali Çehreli wrote: On 02/14/2016 12:03 AM, Beginner-8 wrote: Uh, wait! Forgot about that Socket calls .close() in its dtor Try duplicating the socket handle before handing it over to Socket (not compiled nor tested): import core.sys.posix.unistd; Socket(dup(myHandle)) I think socket handles are duplicatable :p things. Only the last close() would actually close the socket. Ali This recipe works for me! Thanks!
Re: Installing 32 bit libcurl.so.4 on Ubuntu
I'm not 100% sure it's included, but I think so. __ NOOR
Re: Reserving capacity in associative arrays
On Monday, 15 February 2016 at 05:29:23 UTC, sigod wrote: On Monday, 15 February 2016 at 03:22:44 UTC, Jon D wrote: Is there a way to reserve capacity in associative arrays? [snip] Maybe try using this: http://code.dlang.org/packages/aammm Thanks, I wasn't aware of this package. I'll give it a try. --Jon
Re: Reserving capacity in associative arrays
On Monday, 15 February 2016 at 03:22:44 UTC, Jon D wrote: Is there a way to reserve capacity in associative arrays? In some programs I've been writing I've been getting reasonable performance up to about 10 million entries, but beyond that performance is impacted considerably (say, 30 million or 50 million entries). GC stats (via the "--DRT-gcopt=profile:1" option) indicate dramatic increases in gc time, which I'm assuming comes from resizing the underlying hash table. I'm guessing that by preallocating a large size the performance degradation would not be quite so dramatic. The underlying implementation of associative arrays appears to take an initial number of buckets, and there's a private resize() method, but it's not clear if there's a public way to use these. --Jon Maybe try using this: http://code.dlang.org/packages/aammm
Re: nanosecond time
On Saturday, 13 February 2016 at 19:24:44 UTC, ishwar wrote:
I am stumped on need finding interval between two events in a
program execution in nanoseconds. Any sample code will be
appreciated (along with imports needed to make it work):
- time in nanoseconds-now
- do-some processing
- time in nano-second-now
Thanks
As suggested above, use a StopWatch.
I use this (not-very-cross-platform) function for latency
measurement purposes. It is precise on Linux. For Mac OS and
Windows, it's returns an approximation:
version(linux) import core.sys.linux.time;
version(OSX)import core.time;
version(Windows) import core.sys.windows.windows;
static if(is(typeof(clockid_t)))
{
extern(C) nothrow int clock_gettime(clockid_t, timespec*);
}
public ulong getLocalTimestampNS() nothrow @nogc
{
static if(is(typeof(clock_gettime)))
{
timespec ts;
clock_gettime(CLOCK_MONOTONIC_RAW, );
return ts.tv_sec * 10 + ts.tv_nsec;
}
static if(is(typeof(mach_absolute_time)))
{
// IMPORTANT NOTE: mach_absolute_time does not always
return nanoseconds.
// Sometimes it returns other values. We are using it
here as an approximation.
return mach_absolute_time();
}
version (Windows)
{
// Just an approximation
long cnt;
if (QueryPerformanceCounter())
{
return cnt * 500;
}
return 0;
}
}
Reserving capacity in associative arrays
Is there a way to reserve capacity in associative arrays? In some programs I've been writing I've been getting reasonable performance up to about 10 million entries, but beyond that performance is impacted considerably (say, 30 million or 50 million entries). GC stats (via the "--DRT-gcopt=profile:1" option) indicate dramatic increases in gc time, which I'm assuming comes from resizing the underlying hash table. I'm guessing that by preallocating a large size the performance degradation would not be quite so dramatic. The underlying implementation of associative arrays appears to take an initial number of buckets, and there's a private resize() method, but it's not clear if there's a public way to use these. --Jon
Re: D Book page 402 Concurrency FAIL
On Monday, 15 February 2016 at 00:58:54 UTC, Brother Bill wrote: On Sunday, 14 February 2016 at 23:39:33 UTC, cym13 wrote: On Sunday, 14 February 2016 at 22:54:36 UTC, Brother Bill wrote: In "The D Programming Language", page 402, the toy program fails. [...] Can't reproduce with DMD 2.0.70, LDC 0.16.1 or GDC 5.3.0 on Linux x86_64. The code seems to work as intended. It is failing in Windows, not Linux. Can someone reproduce this in Windows with VisualD? Works for me on the command line. I don't have VisualD installed right now, but I can't see how that would make a difference.
Re: joiner: How to iterate over immutable ranges?
On Sunday, 14 February 2016 at 19:32:31 UTC, Bastiaan Veelo wrote: Thanks. I didn't know that iterating a range means mutating its contents. I still don't quite get it, and it is probably because I don't fully understand ranges. I think what confuses me the most is their analogy to containers. It's no problem to iterate over a container of immutable data, but it is for a range. Maybe this [1] will help shed some light. [1] https://www.packtpub.com/books/content/understanding-ranges
Re: joiner: How to iterate over immutable ranges?
On 02/14/2016 11:32 AM, Bastiaan Veelo wrote:
> Thanks. I didn't know that iterating a range means mutating its
> contents.
That's not the case: Just like an iterator, a range must maintain some
state to know which item is next. What needs to be mutated is that
iteration state.
> I still don't quite get it, and it is probably because I don't
> fully understand ranges. I think what confuses me the most is their
> analogy to containers.
Yes, that analogy is the wrong one (and D's slices (or dynamic arrays)
don't help with that).
> It's no problem to iterate over a container of immutable data, but
> it is for a range.
Not true. You can iterate over immutable data. In fact, a string is
nothing but a container of immutable characters yet we can iterate over it.
> I thought that joiner provided a contiguous view on distinct ranges,
> without needing to touch these. Is there another method to traverse a
> range of ranges without making copies or mutation?
Not without making copies but note that the copy that you need to make
is just the slices (i.e. views into data), which consist of just a
length and a pointer fields. If it's acceptable for you, the following
code calls .save on the elements and it works:
import std.algorithm.iteration;
import std.stdio;
import std.array;// <-- ADDED
void main()
{
immutable(string[])[] icycles;
icycles ~= ["one", "two"];
icycles ~= ["three", "four"];
foreach (number; icycles.map!(r => r.save).joiner)
writeln(number);
}
Again, .save on an array is cheap. What will happen is that the original
immutable arrays will be untouched but their proxies returned by .save
will be consumed.
Ali
Re: Implicit conversion from string to custom type?
On 02/14/2016 03:43 PM, Tofu Ninja wrote:
So I wrote a simple ref counted string type because using the built in
strings without the GC is extremely painful. It there any way I can get
strings to implicitly convert to my custom string type?
No, D does not support such implicit conversions.
struct rstring {...}
void fun(rstring s) {...}
...
fun("hello world"); // Currently an error
Would be super nice if it would just call the opAssign when trying to
call fun but I suppose that has some non-obvious problems for why it
does not work that way.
The only way is to be explicit. Three common options:
fun(rstring("hello world"));
fun("hello world".to!rstring);
fun(cast(rstring)"hello world");
Relatedly, user defined types can provide implicit conversions through
'alias this' but unfortunately, current implementation supports only one
such operator.
Ali
Re: D Book page 402 Concurrency FAIL
On Sunday, 14 February 2016 at 23:39:33 UTC, cym13 wrote: On Sunday, 14 February 2016 at 22:54:36 UTC, Brother Bill wrote: In "The D Programming Language", page 402, the toy program fails. [...] Can't reproduce with DMD 2.0.70, LDC 0.16.1 or GDC 5.3.0 on Linux x86_64. The code seems to work as intended. It is failing in Windows, not Linux. Can someone reproduce this in Windows with VisualD?
Implicit conversion from string to custom type?
So I wrote a simple ref counted string type because using the
built in strings without the GC is extremely painful. It there
any way I can get strings to implicitly convert to my custom
string type?
Some way to make this work...
struct rstring {...}
void fun(rstring s) {...}
...
fun("hello world"); // Currently an error
Would be super nice if it would just call the opAssign when
trying to call fun but I suppose that has some non-obvious
problems for why it does not work that way.
Re: D Book page 402 Concurrency FAIL
On Sunday, 14 February 2016 at 22:54:36 UTC, Brother Bill wrote: In "The D Programming Language", page 402, the toy program fails. [...] Can't reproduce with DMD 2.0.70, LDC 0.16.1 or GDC 5.3.0 on Linux x86_64. The code seems to work as intended.
D Book page 402 Concurrency FAIL
In "The D Programming Language", page 402, the toy program fails.
The first fail is that enforce() needs: import std.exception;
The second fail is that when debugging, in Visual Studio 2015
Community Edition,
it fails with this error:
First-change exception: std.format.FormatException Unterminated
format specifier: "%" at
C:\D\dmd2\windows\bin\..\..\src\phobos\std\format.d(830).
Please provide full replacement of this toy program that works
with D version 2.070.0
This is what was entered:
import std.concurrency, std.stdio, std.exception;
void main() {
auto low = 0,
high = 100;
auto tid = spawn();
foreach (i; low .. high) {
writeln("Main thread: ", i);
tid.send(thisTid, i);
enforce(receiveOnly!Tid() == tid);
}
}
void writer() {
for (;;) {
auto msg = receiveOnly!(Tid, int)();
writeln("secondary thread: ", msg[1]);
msg[0].send(thisTid);
}
}
Thank you.
Re: joiner: How to iterate over immutable ranges?
On Sunday, 14 February 2016 at 18:28:11 UTC, Jonathan M Davis wrote: An immutable range fundamentally does not work. The same goes with const. In fact, a type that's immutable is going to fail isInputRange precisely because it can't possibly function as one. While empty and front may be callable on an immutable range, depending on their exact signatures, popFront cannot be, because it has to mutate the range in order to work. Thanks. I didn't know that iterating a range means mutating its contents. I still don't quite get it, and it is probably because I don't fully understand ranges. I think what confuses me the most is their analogy to containers. It's no problem to iterate over a container of immutable data, but it is for a range. I thought that joiner provided a contiguous view on distinct ranges, without needing to touch these. Is there another method to traverse a range of ranges without making copies or mutation?
Re: joiner: How to iterate over immutable ranges?
On Sunday, February 14, 2016 15:24:39 Bastiaan Veelo via Digitalmars-d-learn
wrote:
> Hi,
>
> I am having trouble getting the iteration methods in
> std.algorithm.iteration to work on immutable data:
>
> > import std.algorithm.iteration;
> > import std.stdio;
> >
> > void main()
> > {
> > string[][] cycles;
> > cycles ~= ["one", "two"];
> > cycles ~= ["three", "four"];
> > foreach (number; cycles.joiner) // This works.
> > writeln(number);
> >
> > immutable(string[])[] icycles;
> > icycles ~= ["one", "two"];
> > icycles ~= ["three", "four"];
> > foreach (number; icycles.joiner) // Should this work?
> > writeln(number);
> > }
>
> The error message is:
>
> /d149/f840.d(15): Error: template std.algorithm.iteration.joiner
> cannot deduce function from argument types
> !()(immutable(string[])[]), candidates are:
> /opt/compilers/dmd2/include/std/algorithm/iteration.d(1911):
>std.algorithm.iteration.joiner(RoR, Separator)(RoR r, Separator
> sep) if (isInputRange!RoR && isInputRange!(ElementType!RoR) &&
> isForwardRange!Separator && is(ElementType!Separator :
> ElementType!(ElementType!RoR)))
> /opt/compilers/dmd2/include/std/algorithm/iteration.d(2194):
>std.algorithm.iteration.joiner(RoR)(RoR r) if (isInputRange!RoR
> && isInputRange!(ElementType!RoR))
>
> I had expected this to work. What did I miss?
An immutable range fundamentally does not work. The same goes with const. In
fact, a type that's immutable is going to fail isInputRange precisely
because it can't possibly function as one. While empty and front may be
callable on an immutable range, depending on their exact signatures,
popFront cannot be, because it has to mutate the range in order to work.
Arrays do typically get sliced when they're passed to functions, and array
slices are tail-const (e.g. const(int[]) is sliced as const(int)[]), so
something like
immutable string foo = "hello world";
auto result = foo.startsWith("goodbye");
will compile. But that doesn't work with ranges in general. What you're
doing is probably failing, because icycle[] is immutable(string)[], which is
immutable(char[])[], and it can't iterate over the immutable(char[]). But
regardless, if you try and use immutable with ranges, even if it works in
some cases thanks to how arrays are treated, it's just going to end up
shooting you in the foot in the end. So, I'd advise that you not bother
trying to do much with const or immutable with ranges.
- Jonathan M Davis
Re: Is this a good singleton?
On Sunday, 14 February 2016 at 07:16:54 UTC, Russel Winder wrote: On Sat, 2016-02-13 at 18:58 +, Vladde Nordholm via Digitalmars-d- learn wrote: [...] Following the ACCU consensus: there is never, ever a good Singleton or reason to contemplate using one. Obviously though there are some good ones: about dialogues in GUIs for example. The good/evil-ness of Singleton is definitely in it's use: most people use Singleton wrongly, most uses should be banned. Hence the ACCU consensus. It's all about coupling and mostly testability of code.. Thanks. I'm using David Simcha's singleton now.
Re: Singleton, alias to self?
On Sunday, 14 February 2016 at 13:23:28 UTC, Guillaume Piolat
wrote:
On Sunday, 14 February 2016 at 12:56:51 UTC, Vladde Nordholm
wrote:
I'm not sure of how to use alias efficiently, so I want to
know if I could somehow do this (psuedo-code)
class Singleton
{
//So instead of calling `Singleton.getSingleton()` you just
call `Singleton`
alias this = getSingleon()
//code for singleton...
}
Thanks in advance,
vladde
The "alias newThing = x;" syntax is not allowed with alias
this. It's the only exception.
You have to use
alias getSingleton this;
I've tried and fail to do what you want, even with a templated
class + eponymous trick.
Re: Singleton, alias to self?
On Sunday, 14 February 2016 at 12:56:51 UTC, Vladde Nordholm
wrote:
I'm not sure of how to use alias efficiently, so I want to know
if I could somehow do this (psuedo-code)
class Singleton
{
//So instead of calling `Singleton.getSingleton()` you just
call `Singleton`
alias this = getSingleon()
//code for singleton...
}
Thanks in advance,
vladde
The "alias newThing = x;" syntax is not allowed with alias this.
It's the only exception.
You have to use
alias getSingleton this;
Singleton, alias to self?
I'm not sure of how to use alias efficiently, so I want to know
if I could somehow do this (psuedo-code)
class Singleton
{
//So instead of calling `Singleton.getSingleton()` you just
call `Singleton`
alias this = getSingleon()
//code for singleton...
}
Thanks in advance,
vladde
joiner: How to iterate over immutable ranges?
Hi,
I am having trouble getting the iteration methods in
std.algorithm.iteration to work on immutable data:
import std.algorithm.iteration;
import std.stdio;
void main()
{
string[][] cycles;
cycles ~= ["one", "two"];
cycles ~= ["three", "four"];
foreach (number; cycles.joiner) // This works.
writeln(number);
immutable(string[])[] icycles;
icycles ~= ["one", "two"];
icycles ~= ["three", "four"];
foreach (number; icycles.joiner) // Should this work?
writeln(number);
}
The error message is:
/d149/f840.d(15): Error: template std.algorithm.iteration.joiner
cannot deduce function from argument types
!()(immutable(string[])[]), candidates are:
/opt/compilers/dmd2/include/std/algorithm/iteration.d(1911):
std.algorithm.iteration.joiner(RoR, Separator)(RoR r, Separator
sep) if (isInputRange!RoR && isInputRange!(ElementType!RoR) &&
isForwardRange!Separator && is(ElementType!Separator :
ElementType!(ElementType!RoR)))
/opt/compilers/dmd2/include/std/algorithm/iteration.d(2194):
std.algorithm.iteration.joiner(RoR)(RoR r) if (isInputRange!RoR
&& isInputRange!(ElementType!RoR))
I had expected this to work. What did I miss?
Thanks,
Bastiaan.
Re: Singleton, alias to self?
On Sunday, 14 February 2016 at 12:56:51 UTC, Vladde Nordholm
wrote:
I'm not sure of how to use alias efficiently, so I want to know
if I could somehow do this (psuedo-code)
class Singleton
{
//So instead of calling `Singleton.getSingleton()` you just
call `Singleton`
alias this = getSingleon()
//code for singleton...
}
Thanks in advance,
vladde
"this" is for an instance of class (or struct). There is no
instance of define an alias at that time. I am not sure, but you
can check "opCall" function as static for this. Give it a try at
least.
Re: wrapSocket for socket_t? As wrapFile for FILE*
On Sunday, 14 February 2016 at 07:33:11 UTC, Ali Çehreli wrote:
Maybe another option is to duplicate the socket handle
Sure!
Nevertheless, it is need method for socket_t duplication.
Something like:
class Socket
{
...
static Socket dup(socket_t)
...
}
before giving it to Socket but I am failing to find a
definitive answer or an example.
Re: wrapSocket for socket_t? As wrapFile for FILE*
On 02/14/2016 12:03 AM, Beginner-8 wrote: Uh, wait! Forgot about that Socket calls .close() in its dtor Try duplicating the socket handle before handing it over to Socket (not compiled nor tested): import core.sys.posix.unistd; Socket(dup(myHandle)) I think socket handles are duplicatable :p things. Only the last close() would actually close the socket. Ali
Re: wrapSocket for socket_t? As wrapFile for FILE*
Uh, wait! Forgot about that Socket calls .close() in its dtor
Photoshop programming
Photoshop has the ability to be controlled by scripts and programming languages. For example, C# can be used to access photoshop by adding the appropriate reference and using directives. I believe it is COM based but I am not totally sure. I've tried reading the docs but it's not making much sense. http://www.lunesu.com/uploads/ModernCOMProgramminginD.pdf links at the bottom are down. It says one has to create a wrapper, but then talks like it can be done automatically. I assume that is what project does? But then one has to create an idl, not sure what that is ;\ Any info on how to do this stuff properly?
