Re: Better native D 2D graphics library?
On Monday, 9 February 2015 at 05:50:00 UTC, uri wrote: On Saturday, 7 February 2015 at 23:29:01 UTC, Namespace wrote: On Saturday, 7 February 2015 at 22:09:03 UTC, Gan wrote: Is there a better D graphics library in the works? I'm using SFML(which is very easy and has lots of features) but it seems to use a lot of ram(if you leave it running for a while on a graphic intensive scene) and trying to make it include the dependencies with the compiled executable is complicated. Is there a D 2D graphics library that's just as easy, cross platform, doesn't use X11, allows drawing to off-screen buffers and drawing those to screen? (plus supports nice drawing of shapes, circles, rectangles, lines) I'm probably asking too much- I doubt such a thing exists. I once wrote such a library: https://github.com/Dgame/Dgame But since I left D I don't maintain it. Maybe that will change in the next few weeks. But otherwise you are free to use or improve it. I use Dgame for hobby projects and can definitely recommend it. That's nice to hear! Thank you.
Re: Static method of inner class needs this
On Monday, 9 February 2015 at 07:32:33 UTC, rumbu wrote:
class Outer
{
class Inner
{
static Inner createInner()
{
return new Inner(); //need 'this' to access member
this
}
}
}
Is this a bug?
If Inner is not nested, it works as expected:
class Inner
{
static Inner createInner()
{
return new Inner()
}
}
D version: 2.066.1
In the first case, is there an Inner that is visible outside of
Outer?
If so, the compiler wont know which one your talking about, so
need to specify with this.
Re: Static method of inner class needs this
On Mon, 09 Feb 2015 07:32:32 +, rumbu wrote:
class Outer {
class Inner {
static Inner createInner()
{
return new Inner(); //need 'this' to access member
this
}
}
}
Is this a bug?
strictly speaking, this is not a bug. compiler doesn't do deep analysis
on nested structures/classes to determine if they really require context
pointer. you can use `static class Inner` to tell the compiler that
`Inner` doesn't require any context.
signature.asc
Description: PGP signature
Re: Classes and @disable this()
On Sunday, 8 February 2015 at 19:57:28 UTC, Jonathan M Davis
wrote:
On Sunday, February 08, 2015 17:51:09 bearophile via
Digitalmars-d-learn wrote:
fra:
However making it a compiler error would be far, far better
I think this can be filed in Bugzilla as diagnostic
enhancement:
class Foo {
@disable this();
this(int i) {}
}
void main() {}
The compiler should probably just give you an error telling you
that
disabling the default constructor on classes is illegal. And
since no
default constructor is automatically declared if you declare
another
constructor, there isn't even any point in disabling the
default constructor
(which is probably why no one has been complaining about this).
@disable
this() only makes sense on structs.
Alternatively, it could be accepted (and a no-op) if another
constructor is defined, but an error if not.
Re: Template constructor in a non-template struct.
On Sunday, 8 February 2015 at 22:19:35 UTC, ChrisG wrote: Thanks bearophile. Your first suggestion about making the struct a template is something I considered. However, because of all the code I've already written that approach would force me to use inheritance or convert a ton of functions to templates. Ick. The __ctor syntax looks like the answer to my question. If my struct is used by anyone else though, I'm not sure it would be OK to assume they would even be aware of that syntax. hmmm... Thinking I'll just make it a runtime parameter for now. You could also hide the ugly __ctor() call behind a nicely named factory method.
Worker is not finished while sending message to intermediate worker
I am using programming in D to learn about D language. I wrote
a simple program that spawns a worker and sends it a number to
receive its square as a string. The worker 1 gets the number
squares it and sends to worker 2 (a different function) to get
casted as string which is returned to the worker 1 and thus it
returns it to the main function call. I can write the whole thing
in a single thread. I wrote it to understand about workers
better. I used receive to get the worker 1 act as per the input.
The program is as follows
import std.stdio;
import std.concurrency;
import std.conv;
import core.thread;
void main() {
foreach (int num; 1..100) {
auto square_tid = spawn(square);
square_tid.send(num);
auto square = receiveOnly!string();
writeln(square);
}
}
void square() {
static i = 0;
receive (
(int num) {
auto square = num * num;
writeln(sqaure : Comes in with , num , for , ++i
, time);
auto stringWorker = spawn(stringConverter);
stringWorker.send(thisTid, square, ownerTid);
},
(Tid tid, string str) {
writeln(comes in string);
send(tid, hello);
});
}
void stringConverter() {
static i = 0;
auto params = receiveOnly!(Tid, int, Tid)();
auto stringified = to!string(params[1]); // Stringify the square
writeln(string : Comes in with , params[1], for , ++i ,
time);
params[0].send(params[2], stringified); // params[0] - square
function tid, // params[2] - main function tid
}
I got the answer from stackoverflow @
https://stackoverflow.com/questions/28128383/worker-is-not-finished-while-sending-message-to-intermediate-worker.
But the person who answered my question asked me to post back to
dlang learn to learn more about it. As I spawn the function and a
send a message to stringConverter as it sends a message to the
square function why do I need to embed another receive call
inside the int case as indicated in the answer. How can I avoid
embedding the receive call and why does the person in the second
answer used while(1) to receive the message.
Re: parse string as char
https://github.com/Hackerpilot/libdparse/blob/master/src/std/d/lexer.d#L1491
Re: parse string as char
Of course consuming it dchar by dchar also works: string s = `\tabŁŃ\r\nx`; assert(parseDchar(s) == '\t'); assert(parseDchar(s) == 'a'); assert(parseDchar(s) == 'b'); assert(parseDchar(s) == 'Ł'); assert(parseDchar(s) == 'Ń'); assert(parseDchar(s) == '\r'); assert(parseDchar(s) == '\n'); assert(parseDchar(s) == 'x'); assert(s.empty);
Re: parse string as char
On 2015-02-09 at 03:40, Timothee Cour via Digitalmars-d-learn wrote:
Is there a simple way to parse a string as a char?
eg:
unittest{
assert(parseChar(`a`)=='a');
assert(parseChar(`\n`)=='\n'); //NOTE: I'm looking at `\n` not \n
// should also work with other forms of characters, see
http://dlang.org/lex.html
}
Note, std.conv.to http://std.conv.to doesn't work (`\n`.to!char does not work)
parseEscape does something similar to what you need:
https://github.com/D-Programming-Language/phobos/blob/master/std/conv.d#L3415
Unfortunately it is private and handles only escapes, so here is a modified
version:
import std.range, std.stdio;
dchar parseDchar(Source)(ref Source s)
if (isInputRange!Source isSomeChar!(ElementType!Source))
{
import std.utf, std.conv;
if (s.front != '\\') {
dchar c = decodeFront(s);
return c;
}
s.popFront;
if (s.empty)
throw new Exception(Unterminated escape sequence);
dchar getHexDigit()(ref Source s_ = s) // workaround
{
import std.ascii : isAlpha, isHexDigit;
if (s_.empty)
throw new Exception(Unterminated escape sequence);
s_.popFront();
if (s_.empty)
throw new Exception(Unterminated escape sequence);
dchar c = s_.front;
if (!isHexDigit(c))
throw new Exception(Hex digit is missing);
return isAlpha(c) ? ((c ~0x20) - ('A' - 10)) : c - '0';
}
dchar result;
switch (s.front)
{
case '': result = '\'; break;
case '\'': result = '\''; break;
case '0': result = '\0'; break;
case '?': result = '\?'; break;
case '\\': result = '\\'; break;
case 'a': result = '\a'; break;
case 'b': result = '\b'; break;
case 'f': result = '\f'; break;
case 'n': result = '\n'; break;
case 'r': result = '\r'; break;
case 't': result = '\t'; break;
case 'v': result = '\v'; break;
case 'x':
result = getHexDigit() 4;
result |= getHexDigit();
break;
case 'u':
result = getHexDigit() 12;
result |= getHexDigit() 8;
result |= getHexDigit() 4;
result |= getHexDigit();
break;
case 'U':
result = getHexDigit() 28;
result |= getHexDigit() 24;
result |= getHexDigit() 20;
result |= getHexDigit() 16;
result |= getHexDigit() 12;
result |= getHexDigit() 8;
result |= getHexDigit() 4;
result |= getHexDigit();
break;
default:
throw new Exception(Unknown escape character ~
to!string(s.front));
}
if (s.empty)
throw new Exception(Unterminated escape sequence);
s.popFront();
return result;
}
dstring parseString(Source)(Source s)
if (isInputRange!Source isSomeChar!(ElementType!Source))
{
import std.array;
dchar[] result;
auto app = appender(result);
while (!s.empty)
app.put(parseDchar(s));
return app.data;
}
unittest
{
assert(parseString(``) == d);
assert(parseString(`abc`) == abcd);
assert(parseString(`abc\\n\\n\\n`) == abc\\n\\n\\nd);
assert(parseString(`ąćę\\nłńó`) == ąćę\\nłńód);
assert(parseString(`abc\\\nx`) == abc\\\nxd);
assert(parseString(`\tabc\r\nx`) == \tabc\r\nxd);
assert(parseString(` \x20 `) ==d);
}
Re: How to write similar code D?
On 2015-02-10 at 01:41, bearophile wrote: auto query = iota(2, 12) .map!(c = Tuple!(int,length, int,height, int,hypotenuse) (2 * c, c ^^ 2 - 1, c ^^ 2 + 1)) .map!(x = %3d%4d%4d.format(x.height, x.hypotenuse, x.length)); I took advantage of the fact that all elements were of the same type: auto query = iota(2, 2 + 10) .map!(c = [Length: 2 * c, Height: c * c - 1, Hypotenuse: c * c + 1]) .map!(x = format(%4d%4d%4d, x[Height], x[Hypotenuse], x[Length])); ... and was surprised that it worked straight away. :) But definitely this looks better and less complicated: auto query = iota(2, 12) .map!(c = tuple(c ^^ 2 - 1, c ^^ 2 + 1, 2 * c)); foreach (x; query) writefln(%4d%4d%4d, x[]); It's the foreach version, since `each` isn't officially out yet.
Re: How to write similar code D?
On Tuesday, 10 February 2015 at 01:31:54 UTC, FG wrote: On 2015-02-10 at 01:41, bearophile wrote: auto query = iota(2, 12) .map!(c = Tuple!(int,length, int,height, int,hypotenuse) (2 * c, c ^^ 2 - 1, c ^^ 2 + 1)) .map!(x = %3d%4d%4d.format(x.height, x.hypotenuse, x.length)); I took advantage of the fact that all elements were of the same type: auto query = iota(2, 2 + 10) .map!(c = [Length: 2 * c, Height: c * c - 1, Hypotenuse: c * c + 1]) .map!(x = format(%4d%4d%4d, x[Height], x[Hypotenuse], x[Length])); ... and was surprised that it worked straight away. :) But definitely this looks better and less complicated: auto query = iota(2, 12) .map!(c = tuple(c ^^ 2 - 1, c ^^ 2 + 1, 2 * c)); foreach (x; query) writefln(%4d%4d%4d, x[]); It's the foreach version, since `each` isn't officially out yet. Thank you.
Re: To write such an expressive code D
On 02/09/2015 08:17 PM, Dennis Ritchie wrote: Ali, and you can write it without using the function iota() and map? No because the a..b syntax is not a D language construct that we can use anywhere that it makes sense. It only works as number ranges inside foreach loops, when indexing slices, and case value ranges. Also no, because there is no equivalent of F#'s - syntax, we have to use map. %(%.15g\n%).writefln(iota(0, PI/2, PI/2/9).map!sin); I just need that code was only used features of the language without using library functions. You may only use the function sin(). I am waiting to see a language solution that does not use even sin(). :o) Ali
Re: function and variable
On Tuesday, 10 February 2015 at 03:59:22 UTC, Rikki Cattermole wrote: That's a bug. It should be using the function pointer. UFCS call should abide by the same scoping rules as anything else. https://issues.dlang.org/show_bug.cgi?id=14161 I thought that's how UFCS was explicitly designed? Global symbols only, yes?
Re: To write such an expressive code D
On Monday, 9 February 2015 at 20:16:45 UTC, Ali Çehreli wrote:
Yes, but apparently D's default precision for output is less
than F#'s so how about the following? :p
%(%.15g\n%).writefln(iota(0, PI/2, PI/2/9).map!sin);
Just for demonstration, I would not write anything like that
but the following is fine because now the format becomes the
second parameter: :)
iota(0, PI/2, PI/2/9).map!sin.writeF(%(%.15g\n%));
void writeF(R)(R range, string format)
{
return writefln(format, range);
}
Ali, and you can write it without using the function iota() and
map?
%(%.15g\n%).writefln(iota(0, PI/2, PI/2/9).map!sin);
I just need that code was only used features of the language
without using library functions. You may only use the function
sin().
function and variable
Hi!
I think this code should not be compiled without any warning:
import std.stdio;
void f(int a) {
writeln(it's a function! : , a);
}
void main() {
auto f = function (int a) {writeln(It's a variable! : ,
a);};
5.f();
f(5);
}
Output:
it's a function! : 5
It's a variable! : 5
WBR,
Fyodor.
Re: function and variable
On Tuesday, 10 February 2015 at 03:59:22 UTC, Rikki Cattermole wrote: That's a bug. It should be using the function pointer. UFCS call should abide by the same scoping rules as anything else. https://issues.dlang.org/show_bug.cgi?id=14161 Moreover. If the function is not defined (only pointer), I get this error: aa.d(5): Error: no property 'f' for type 'int' when try use 5.f();
Re: Intended to be able to RefCount an interface?
On Tuesday, 10 February 2015 at 05:09:00 UTC, Jakob Ovrum wrote:
On Tuesday, 10 February 2015 at 04:44:55 UTC, weaselcat wrote:
Thread title.
interface Itest{
}
class testclass : Itest{
}
void main()
{
import std.typecons;
auto test = RefCounted!Itest(new testclass());
}
If you change the refcounted to type testclass it doesn't
compile because refcounted doesn't support classes.
Is this a bug, or intended?
I think this is a bug, and that the current RefCounted needs to
reject interfaces.
I assumed as much, thanks.
AFAIK, it is intended that RefCounted!SomeClass is supposed to
reference-count the actual class instance, not its reference,
which is what RefCounted!SomeInterface currently does.
Is there currently an enhancement request open for this on the
bug tracker? I cannot find anything.
Re: To write such an expressive code D
On Tuesday, 10 February 2015 at 06:17:17 UTC, Ali Çehreli wrote: On 02/09/2015 08:17 PM, Dennis Ritchie wrote: Ali, and you can write it without using the function iota() and map? No because the a..b syntax is not a D language construct that we can use anywhere that it makes sense. It only works as number ranges inside foreach loops, when indexing slices, and case value ranges. Also no, because there is no equivalent of F#'s - syntax, we have to use map. %(%.15g\n%).writefln(iota(0, PI/2, PI/2/9).map!sin); I just need that code was only used features of the language without using library functions. You may only use the function sin(). I am waiting to see a language solution that does not use even sin(). :o) Ali Thank you.
Re: Classes and @disable this()
On 2/8/15 2:57 PM, Jonathan M Davis via Digitalmars-d-learn wrote:
On Sunday, February 08, 2015 17:51:09 bearophile via Digitalmars-d-learn wrote:
fra:
However making it a compiler error would be far, far better
I think this can be filed in Bugzilla as diagnostic enhancement:
class Foo {
@disable this();
this(int i) {}
}
void main() {}
The compiler should probably just give you an error telling you that
disabling the default constructor on classes is illegal. And since no
default constructor is automatically declared if you declare another
constructor, there isn't even any point in disabling the default constructor
(which is probably why no one has been complaining about this). @disable
this() only makes sense on structs.
Why? I think it's perfectly acceptable.
What should be illegal is if you extend Foo and don't @disable this on
the derivative.
-Steve
Re: Static method of inner class needs this
On 2/9/15 4:30 AM, ketmar wrote:
On Mon, 09 Feb 2015 07:32:32 +, rumbu wrote:
class Outer {
class Inner {
static Inner createInner()
{
return new Inner(); //need 'this' to access member
this
}
}
}
Is this a bug?
strictly speaking, this is not a bug. compiler doesn't do deep analysis
on nested structures/classes to determine if they really require context
pointer. you can use `static class Inner` to tell the compiler that
`Inner` doesn't require any context.
To expand on this, nested classes (that is, a class nested inside
another class) REQUIRE a pointer to the outer class instance (accessed
via hidden member outer). The reason for this is Java portability.
Seriously :)
-Steve
Re: To write such an expressive code D
On Monday, 9 February 2015 at 20:03:00 UTC, Vladimir Panteleev wrote: On Monday, 9 February 2015 at 19:57:23 UTC, Ali Çehreli wrote: writefln(%(%.15g\n%), sins); In 2.067, you can write: iota(0, PI/2, PI/2/9).map!sin.each!writeln; March 1!
Re: Worker is not finished while sending message to intermediate worker
On 02/09/2015 11:46 AM, Ali Çehreli wrote:
threads normally start one [or] more worker threads and
send tasks to those threads
Accordingly, the following program uses just three threads:
import std.stdio;
import std.concurrency;
import std.conv;
import core.thread;
struct Terminate
{}
void main() {
auto square_tid = spawn(square);
foreach (int num; 1..100) {
square_tid.send(num);
auto square = receiveOnly!string();
writeln(square);
}
square_tid.send(Terminate());
}
void square() {
auto i = 0;
bool done = false;
auto stringWorker = spawn(stringConverter, ownerTid);
while (!done) {
receive (
(Terminate message) {
stringWorker.send(message);
done = true;
},
(int num) {
auto square = num * num;
writeln(sqaure : Comes in with ,
num , for , ++i , time);
stringWorker.send(square);
});
}
}
void stringConverter(Tid destination) {
auto i = 0;
bool done = false;
while (!done) {
receive (
(Terminate message) {
done = true;
},
(int num) {
auto stringified = num.to!string;
writeln(string : Comes in with ,
num, for , ++i , time);
destination.send(stringified);
});
}
}
Ali
Binding C++ value types
When binding C++ value types you might want to use them by placing them on the D-Stack. This however seems to be not supported as the mangling for the constructor is completely wrong. Is this supposed to work? Kind Regards Benjamin Thaut
Re: To write such an expressive code D
On Monday, 9 February 2015 at 19:40:42 UTC, Dennis Ritchie wrote: Good evening. Is it possible to D something to replace the container on the F#, which displays the values of the sine from 0 to 90 degrees with an interval of 10 degrees: let pi = Math.PI let sins = [for x in 0.0..pi / 2.0 / 9.0..pi / 2.0 - sin x] sins.Dump() Output: 0 0,17364817766693 0,342020143325699 0,5 0,642787609686539 0,76603118978 0,866025403784439 0,939692620785908 0,984807753012208 1 P.S. Interested in code that will be as impressive as this. In General, I would like to see something akin to D. iota(0, 91, 10).map!sin.writeln or something like that.
Re: To write such an expressive code D
On 02/09/2015 11:45 AM, Tobias Pankrath wrote:
iota(0, 91, 10).map!sin.writeln
or something like that.
Yes: :)
import std.math;
import std.stdio;
import std.range;
import std.algorithm;
void main()
{
const beg = 0.0L;
const interval = PI_2 / 9;
const end = PI_2 + interval;
auto sins = iota(beg, end, interval).map!sin;
writefln(%(%.15g\n%), sins);
}
0
0.17364817766693
0.342020143325669
0.5
0.642787609686539
0.76603118978
0.866025403784439
0.939692620785908
0.984807753012208
1
Ali
Re: Classes and @disable this()
On Monday, February 09, 2015 13:29:22 Steven Schveighoffer via
Digitalmars-d-learn wrote:
On 2/8/15 2:57 PM, Jonathan M Davis via Digitalmars-d-learn wrote:
On Sunday, February 08, 2015 17:51:09 bearophile via Digitalmars-d-learn
wrote:
fra:
However making it a compiler error would be far, far better
I think this can be filed in Bugzilla as diagnostic enhancement:
class Foo {
@disable this();
this(int i) {}
}
void main() {}
The compiler should probably just give you an error telling you that
disabling the default constructor on classes is illegal. And since no
default constructor is automatically declared if you declare another
constructor, there isn't even any point in disabling the default constructor
(which is probably why no one has been complaining about this). @disable
this() only makes sense on structs.
Why? I think it's perfectly acceptable.
What should be illegal is if you extend Foo and don't @disable this on
the derivative.
Why would it we even allow it? What benefit is there? It's meaningless.
@disable this(); is for disabling the init property on structs. Classes
themselves have no init values - and their references have null as their
init value.
The default constructor already follows sensible rules where it's not
generated if another constructor is declared, and derived classes have to
call a base class constructor if the base class doesn't have a default
constructor.
- Jonathan M Davis
Re: How to write similar code D?
Dennis Ritchie:
Tell me, please, how to write similar С# code D:
This is more or less exactly the same:
void main() {
import std.stdio, std.range, std.algorithm, std.typecons,
std.format;
auto query = iota(2, 12)
.map!(c = Tuple!(int,length, int,height,
int,hypotenuse)
(2 * c, c ^^ 2 - 1, c ^^ 2 + 1))
.map!(x = %3d%4d%4d.format(x.height,
x.hypotenuse, x.length));
foreach (immutable x; query)
x.writeln;
}
But often you write something more like this in D using the
latest version of the compiler:
void main() {
import std.stdio, std.range, std.algorithm, std.typecons;
iota(2, 12)
.map!(c = tuple(c ^^ 2 - 1, c ^^ 2 + 1, 2 * c))
.each!(x = writefln(%3d%4d%4d, x[]));
}
Bye,
bearophile
Re: To write such an expressive code D
On 02/09/2015 12:05 PM, Dennis Ritchie wrote:
On Monday, 9 February 2015 at 20:03:00 UTC, Vladimir Panteleev wrote:
On Monday, 9 February 2015 at 19:57:23 UTC, Ali Çehreli wrote:
writefln(%(%.15g\n%), sins);
In 2.067, you can write:
iota(0, PI/2, PI/2/9).map!sin.each!writeln;
March 1!
Yes, but apparently D's default precision for output is less than F#'s
so how about the following? :p
%(%.15g\n%).writefln(iota(0, PI/2, PI/2/9).map!sin);
Just for demonstration, I would not write anything like that but the
following is fine because now the format becomes the second parameter: :)
iota(0, PI/2, PI/2/9).map!sin.writeF(%(%.15g\n%));
void writeF(R)(R range, string format)
{
return writefln(format, range);
}
Ali
Re: Classes and @disable this()
On 2/9/15 3:15 PM, Jonathan M Davis via Digitalmars-d-learn wrote:
On Monday, February 09, 2015 13:29:22 Steven Schveighoffer via
Digitalmars-d-learn wrote:
On 2/8/15 2:57 PM, Jonathan M Davis via Digitalmars-d-learn wrote:
On Sunday, February 08, 2015 17:51:09 bearophile via Digitalmars-d-learn wrote:
fra:
However making it a compiler error would be far, far better
I think this can be filed in Bugzilla as diagnostic enhancement:
class Foo {
@disable this();
this(int i) {}
}
void main() {}
The compiler should probably just give you an error telling you that
disabling the default constructor on classes is illegal. And since no
default constructor is automatically declared if you declare another
constructor, there isn't even any point in disabling the default constructor
(which is probably why no one has been complaining about this). @disable
this() only makes sense on structs.
Why? I think it's perfectly acceptable.
What should be illegal is if you extend Foo and don't @disable this on
the derivative.
Why would it we even allow it? What benefit is there? It's meaningless.
@disable this(); is for disabling the init property on structs. Classes
themselves have no init values - and their references have null as their
init value.
The default constructor already follows sensible rules where it's not
generated if another constructor is declared, and derived classes have to
call a base class constructor if the base class doesn't have a default
constructor.
Well, if I do this:
class C {}
I can do this:
new C();
Mechanisms to disable this are kind of awkward. I can define this() as
private, but that doesn't help for intra-module calls.
static class C doesn't work.
It really is only useful in the case where you don't want to define a
constructor. Which probably means -- you don't want to use a class anyway ;)
But for completeness, it seems like I should be able to have the option
of disabling something the compiler does by default. Even if it's next
to useless.
-Steve
Re: Worker is not finished while sending message to intermediate worker
On Monday, 9 February 2015 at 20:11:09 UTC, Ali Çehreli wrote:
On 02/09/2015 11:46 AM, Ali Çehreli wrote:
threads normally start one [or] more worker threads and
send tasks to those threads
Accordingly, the following program uses just three threads:
import std.stdio;
import std.concurrency;
import std.conv;
import core.thread;
struct Terminate
{}
void main() {
auto square_tid = spawn(square);
foreach (int num; 1..100) {
square_tid.send(num);
auto square = receiveOnly!string();
writeln(square);
}
square_tid.send(Terminate());
}
void square() {
auto i = 0;
bool done = false;
auto stringWorker = spawn(stringConverter, ownerTid);
while (!done) {
receive (
(Terminate message) {
stringWorker.send(message);
done = true;
},
(int num) {
auto square = num * num;
writeln(sqaure : Comes in with ,
num , for , ++i , time);
stringWorker.send(square);
});
}
}
void stringConverter(Tid destination) {
auto i = 0;
bool done = false;
while (!done) {
receive (
(Terminate message) {
done = true;
},
(int num) {
auto stringified = num.to!string;
writeln(string : Comes in with ,
num, for , ++i , time);
destination.send(stringified);
});
}
}
Ali
Hi Ali,
Thanks for your book :) I am using it for learning D. I want the
stringConverter to send a message to square which in turn
messages the main function with string hello. So are you saying
that message is not delivered to square from stringWorker. How
does embedding the receive call inside the int in stackoverflow
answer receives the message? It seems silly but how can I keep my
threads alive to receive messages? Thanks a lot again. Please
correct me if I am wrong anywhere.
hasmap with tuple as key
Is there any drawback of doing this: string[Tuple!(int, int)] a; Especially performance one. Thanks.
Re: Static method of inner class needs this
On Monday, 9 February 2015 at 09:30:55 UTC, ketmar wrote: ... you can use `static class Inner` to tell the compiler that `Inner` doesn't require any context. Thank you, static qualifier works. I thought in C# terms where a static class means anything else.
Re: Learning to XML with D
What I don't quite grab is the construct (in Element e) , especially the *in* part. Function parameters in D can be qualified as in or out, optionally: But of course. Actually I kinda found out just a little while after posting the question. Asking questions is a great way to figure out the answer, so thank you for reading mines ;-) Thank you for your answer too, which consolidates my guess and makes me think I still have some thinking to do about the life of a function parameter. I was a bit puzzled too as to where the Element e comes from, how is it that it's already instanciated and all. Well, I've just found the relevant part of the documentation. To be honest, said documentation is not always easy to navigate or to decrypt. I sense some potential for progress here.
Re: Learning to XML with D
my dom.d works in a familiar way OK, will check it useful for scraping html sites. Not exactly what I'm doing, but close. I'm in the midst of a self-training spree, and what I use as test-tubes fodder is the following : a collection of 300+ html files constituting an electronic version of a technical book. My intent is to generate a clickable table of contents, by parsing the files for css styles specific to section headers. The first leg of the journey was to normalize styles accross the bunch. That is done, more or less. I already have a proto-toc, but not entirely satisfying : lacks handles for propper styling, and the way I arrived there is kinda brutish. One hurdle I haven't overcame yet is that the text content, and the section headers themsleves, contain some html tags (well, the book /is/ about html, among other things). For example, some section headers are rendered as two bold lines, with a fat br/ in the middle, and b/b around. So when I parse the payload of the p element, I end up with some lt;br/gt; in the middle of a sentence. Survivable, but unclean. So yeah, I'll give it another try with your dom.d
Re: Better native D 2D graphics library?
On Saturday, 7 February 2015 at 22:09:03 UTC, Gan wrote: Is there a better D graphics library in the works? I'm using SFML(which is very easy and has lots of features) but it seems to use a lot of ram(if you leave it running for a while on a graphic intensive scene) and trying to make it include the dependencies with the compiled executable is complicated. Is there a D 2D graphics library that's just as easy, cross platform, doesn't use X11, allows drawing to off-screen buffers and drawing those to screen? (plus supports nice drawing of shapes, circles, rectangles, lines) I'm probably asking too much- I doubt such a thing exists. SDL 2.x can do that with renderers.
Re: Worker is not finished while sending message to intermediate worker
On 02/09/2015 12:34 PM, xtreak wrote: I want the stringConverter to send a message to square which in turn messages the main function with string hello. Your code did almost that but there was a bug (which I've pointed out). So are you saying that message is not delivered to square from stringWorker. Not in your code due to that bug but the program that I've shown does exactly what you want. How does embedding the receive call inside the int in stackoverflow answer receives the message? Once one receive() is executed, the program flow continues with further expressions. The suggestion that you received was making square() wait a second message. It need not be embedded at all. All it is needed was a second receive() call. That's all... However, that is not what you intended anyway. You wanted stringConverter() to send a message to main(). So, just forget about that embeded receive and either do what my program did or fix the bug. :) (See my earlier message.) It seems silly but how can I keep my threads alive to receive messages? By having an infinite loop like 'while (!done)'. (Please see my program.) Ali
To write such an expressive code D
Good evening. Is it possible to D something to replace the container on the F#, which displays the values of the sine from 0 to 90 degrees with an interval of 10 degrees: let pi = Math.PI let sins = [for x in 0.0..pi / 2.0 / 9.0..pi / 2.0 - sin x] sins.Dump() Output: 0 0,17364817766693 0,342020143325699 0,5 0,642787609686539 0,76603118978 0,866025403784439 0,939692620785908 0,984807753012208 1 P.S. Interested in code that will be as impressive as this. In General, I would like to see something akin to D.
Re: To write such an expressive code D
Thank you, Tobias Pankrath and Ali Çehreli.
Re: signal handling
On Saturday, 7 February 2015 at 18:30:00 UTC, Danny wrote: [snip] Seems to work fine so far. Not sure whether it's safe to raise() inside a signal handler. Calling raise() without reinstalling the old signal handler is a very bad idea, I [snip] I'm not sure that it's really safe to call raise in the handler. Even C printf() is potentially unsafe leading to recommendations to use only re-entrant functions. I would not expect raise() to be safe (ex. never allocates memory or calls gc somewhere down the line). [snip] Yeah,I don't think that EINTR and flag-checking is even safe. What if you check the flag (and see nothing happened) and then go back to the loop and block (in read() or whatever), and right after the flag checking, unbeknowst to you the signal handler sets the flag, returns, and only then you block in read()? You'd block forever. Yes, pretty much. Do you know signalfd() ? Yes, and I'm looking at using it. I know how it is with external libaries, they always block at the silliest of times. But I've had one (OKAPI) which gave me the FD back, so I could select() on a bunch FDs in my mainloop. In that case, signalfd() was nice since it showed up as a normal read ready in select(), i.e. as a normal event source. Might be worth a try in your case? [snip] so I'm thinking now of leveraging std.signals but I'm not sure that will be reliable. Hmm, I don't know that one yet. Again, probably not safe in sigaction, but using D's slots/signals to communicate that a posix signal has been received and must be handled. Along with signalfd(), I expect it will let me trigger object destruction.
Re: To write such an expressive code D
On Monday, 9 February 2015 at 19:57:23 UTC, Ali Çehreli wrote: writefln(%(%.15g\n%), sins); In 2.067, you can write: iota(0, PI/2, PI/2/9).map!sin.each!writeln;
How to write similar code D?
Tell me, please, how to write similar С# code D:
using System;
using System.Linq;
public class Test
{
public static void Main()
{
var query = Enumerable.Range(2, 10)
.Select(c = new { Length = 2 * c, Height = c * c - 1,
Hypotenuse = c * c + 1 })
.Select(x = string.Format({0,4}{1,4}{2,4}, x.Height,
x.Hypotenuse, x.Length));
foreach (var x in query)
Console.WriteLine(x);
}
}
Output:
3 5 4
8 10 6
15 17 8
24 26 10
35 37 12
48 50 14
63 65 16
80 82 18
99 101 20
120 122 22
Re: internal compiler error with immutable
On 02/08/2015 05:21 AM, Danny wrote:
The obvious
bool opEquals(immutable(C) b) immutable {
return value == b.value;
}
doesn't work. Probably have to override the one from Object ? Even
though I don't really use polymorphism here.
override bool opEquals(Object b) immutable {
return value == (cast(immutable(C)) b).value;
}
Nope. Doesn't work (or compile) either.
Yes, opEquals for classes has a particular syntax:
http://ddili.org/ders/d.en/object.html#ix_object.opEquals
Remember that 'const' binds to immutable as well. The following works
with at least git head:
override bool opEquals(Object b) const {
auto rhs = cast(C)b;
return rhs (value == rhs.value);
}
Ali
Re: signal handling
Hmmm... Just found https://www.securecoding.cert.org/confluence/display/seccode/void+SIG33-C.+Do+not+recursively+invoke+the+raise%28%29+function, the bottom part Compliant Solution (POSIX) does raise() in the signal handler. However, I can't find it in the POSIX standard at http://pubs.opengroup.org/onlinepubs/009695399/functions/sigaction.html. But https://www.securecoding.cert.org/confluence/display/seccode/SIG30-C.+Call+only+asynchronous-safe+functions+within+signal+handlers lists the async-safe functions. raise() and sigaction() are in it. But _Exit() is, too.
Re: function and variable
On 10/02/2015 4:28 p.m., Fyodor Ustinov wrote:
Hi!
I think this code should not be compiled without any warning:
import std.stdio;
void f(int a) {
writeln(it's a function! : , a);
}
void main() {
auto f = function (int a) {writeln(It's a variable! : , a);};
5.f();
f(5);
}
Output:
it's a function! : 5
It's a variable! : 5
WBR,
Fyodor.
That's a bug. It should be using the function pointer.
UFCS call should abide by the same scoping rules as anything else.
https://issues.dlang.org/show_bug.cgi?id=14161
Re: Worker is not finished while sending message to intermediate worker
On 02/09/2015 08:00 AM, xtreak wrote:
I am using programming in D to learn about D language. I wrote a
simple program that spawns a worker and sends it a number to receive its
square as a string. The worker 1 gets the number squares it and sends to
worker 2 (a different function) to get casted as string which is
returned to the worker 1 and thus it returns it to the main function
call. I can write the whole thing in a single thread. I wrote it to
understand about workers better. I used receive to get the worker 1 act
as per the input. The program is as follows
import std.stdio;
import std.concurrency;
import std.conv;
import core.thread;
void main() {
foreach (int num; 1..100) {
auto square_tid = spawn(square);
square_tid.send(num);
auto square = receiveOnly!string();
writeln(square);
}
}
void square() {
static i = 0;
receive (
(int num) {
auto square = num * num;
writeln(sqaure : Comes in with , num , for , ++i ,
time);
auto stringWorker = spawn(stringConverter);
stringWorker.send(thisTid, square, ownerTid);
},
(Tid tid, string str) {
writeln(comes in string);
send(tid, hello);
});
}
void stringConverter() {
static i = 0;
auto params = receiveOnly!(Tid, int, Tid)();
auto stringified = to!string(params[1]); // Stringify the square
writeln(string : Comes in with , params[1], for , ++i , time);
params[0].send(params[2], stringified); // params[0] - square
function tid, // params[2] - main function tid
}
I got the answer from stackoverflow @
https://stackoverflow.com/questions/28128383/worker-is-not-finished-while-sending-message-to-intermediate-worker.
But the person who answered my question asked me to post back to dlang
learn to learn more about it. As I spawn the function and a send a
message to stringConverter as it sends a message to the square function
why do I need to embed another receive call inside the int case as
indicated in the answer. How can I avoid embedding the receive call and
why does the person in the second answer used while(1) to receive the
message.
Let me answer your question about 'value' first. You said on StackOverflow:
Why does it have the value = 0 as its obvious in the code.
I decided to use the value received to keep the example as simple as
possible. Note that later examples use a special type Terminate to
request termination:
int value = 0;
while (value = 0) { // -- Yes, obvious at first
value = receiveOnly!int(); // -- But may change here
// ...
}
In message passing, threads normally start one more worker threads and
send tasks to those threads. In your example, your thread threads that
live for a very short time. In the case of square(), it creates a thread
for every request that it receives.
There is technically nothing wrong with that. However, it will be a good
idea to ensure that threads are alive when messages are sent to them.
This is not the case in your code.
For example, square() starts a thread, sends a message to it, and leaves
the receive() call. When stringConverter() sends the message, that
message will go to the main() thread. square() has executed its
receive() call and about to exit. In other words, the message comes in
string will never be printed.
Again, nothing wrong with it; just stating the obvious... :)
If you want main() to receive stringConverter()'s message, then there is
a bug in stringConverter() because it sends the message to square()
which will never receive it:
params[0].send(/* ... */);
should be
params[2].send(/* ... */);
And then main() complains because it should receive just a string:
Unexpected message type: expected 'string', got
'std.typecons.Tuple!(Tid, string).Tuple'
so the call should actually be
params[2].send(stringified);
Now it works. :)
Ali
Re: function and variable
On Tuesday, 10 February 2015 at 04:11:43 UTC, Vlad Levenfeld wrote: On Tuesday, 10 February 2015 at 03:59:22 UTC, Rikki Cattermole wrote: That's a bug. It should be using the function pointer. UFCS call should abide by the same scoping rules as anything else. https://issues.dlang.org/show_bug.cgi?id=14161 I thought that's how UFCS was explicitly designed? Global symbols only, yes? IMHO even if it is not a bug, it is a feature - it should not be compiled without notice. WBR, Fyodor.
Re: function and variable
On Tuesday, 10 February 2015 at 04:20:27 UTC, Fyodor Ustinov wrote: IMHO even if it is not a bug, it is a feature - it should not be compiled without notice. WBR, Fyodor. Agreed, should be a warning at least.
Intended to be able to RefCount an interface?
Thread title.
interface Itest{
}
class testclass : Itest{
}
void main()
{
import std.typecons;
auto test = RefCounted!Itest(new testclass());
}
If you change the refcounted to type testclass it doesn't compile
because refcounted doesn't support classes.
Is this a bug, or intended?
Re: Binding C++ value types
On Monday, 9 February 2015 at 19:30:32 UTC, Benjamin Thaut wrote: When binding C++ value types you might want to use them by placing them on the D-Stack. This however seems to be not supported as the mangling for the constructor is completely wrong. Is this supposed to work? Kind Regards Benjamin Thaut See https://issues.dlang.org/show_bug.cgi?id=14086 I can't see any reason why it should not to work. It is a very valid use case. Nic
Re: hasmap with tuple as key
On Monday, 9 February 2015 at 21:22:29 UTC, Ondra wrote: Is there any drawback of doing this: string[Tuple!(int, int)] a; Especially performance one. Thanks. Tuples are really just structs generated on the fly, so they are very fast. Hashmaps use the GC, though, so keep that in mind.
Re: Intended to be able to RefCount an interface?
On Tuesday, 10 February 2015 at 04:44:55 UTC, weaselcat wrote:
Thread title.
interface Itest{
}
class testclass : Itest{
}
void main()
{
import std.typecons;
auto test = RefCounted!Itest(new testclass());
}
If you change the refcounted to type testclass it doesn't
compile because refcounted doesn't support classes.
Is this a bug, or intended?
I think this is a bug, and that the current RefCounted needs to
reject interfaces. AFAIK, it is intended that
RefCounted!SomeClass is supposed to reference-count the actual
class instance, not its reference, which is what
RefCounted!SomeInterface currently does.
