Re: How do I obtain the default hash of a user-defined struct
On Wednesday, 2 April 2014 at 22:07:36 UTC, FreeSlave wrote: Contents of struct are compared field by field using comparison for the type of each field. Dynamic arrays are compared by contents. If you want to compare them by pointer use .ptr property. opEquals and opCmp are not about hashing, I believe. They are just operators to help when dealing with chaining when different objects have same hash (since hash may be not unique) Thanks, I'll post the other questions in separate threads.
Cannot access static overloaded function?
I have 2 modules:
module A;
public class A {
private static void foo() {}
public static void foo(int) {}
}
module B;
import A;
public class B {
public static void bar() { A.foo(0); }
}
Error: class A.A member foo is not accessible
Re: Why is SysTime.init invalid?
On Tuesday, April 01, 2014 03:54:07 Jonathan M Davis wrote: > On Tuesday, April 01, 2014 05:35:28 ed wrote: > > OK, lazy me just read the std.satetime article again. It appears > > the design is for no invalid values and it is currently a known > > limitation due to CTFE. > > > > --- > > d_time_nan There is no equivalent. SysTime.init, which has a null > > TimeZone object, would be the closest, but once CTFE advances to > > the point that you can new up class objects with it, > > SysTime.init's timezone will be LocalTime, so don't rely on > > SysTime.init being invalid. std.datetime in general tries to > > avoid having any invalid states for any of its types. It's > > intended that creating such values be impossible. > > --- > > > > I would still like to know if there is a way around this so I can > > have my struct default init. > > You can certainly have a struct with a SysTime member, but there's no way > for it to use that SysTime without first assigning a valid value to it - at > least, not without segfaulting when it tries to use the SysTime in any > context which it would use its timezone member. > > If you really want to have the SysTime be useable in the init value of your > struct, then you can make it so that each of its member functions which use > the SysTime member check it for validity first (or have a separate bool > which indicates whether the SysTime has been assigned to or not), in which > case, it could assign something like SysTime(0) to it, which would be the > valid equivalent of SysTime.init. > > Unfortunately, that does add extra overhead, but there isn't any way around > it if you want to have the SysTime be used without having the user of the > struct assign to it first. It's pretty much the same boat that SysTime > itself is in. I could make it so that it checks the timezone for null every > time it's used and assign LocalTime to it if it's null, but that adds > constant overhead. My decision was that it was better to just live with the > fact that SysTime.init is invalid. It's debatable though, as it's a > trade-off. Actually, after thinking about this more after someone opened a bug on the fact that SysTime.init.toString() segfaults (since the timezone is null) https://d.puremagic.com/issues/show_bug.cgi?id=12507 I think that I have a solution. It's now possible to default-intialize the timezonet to UTC so that SysTime.init is equivalent to SysTime(0, UTC()). It's not ideal, because it's not SysTime(0, LocalTime()), and SysTime normally defaults to LocalTime, but it will never be possible to default-initialize it to LocalTime thanks to the fact that it has to call tzset when it's initialized. You can look my comments in the bug for more details. I've opened a pull request with those changes, so the next release will probably have a valid SysTime.init, even if it's not SysTime(0, LocalTime()) like would be ideal. - Jonathan M Davis
Re: unicode console output
Tnx, chcp 65001 and Lucida font out correct string.
Re: template interface and delegates
On Tuesday, 1 April 2014 at 19:55:05 UTC, Steven Schveighoffer wrote: On Tue, 01 Apr 2014 15:47:42 -0400, anonymous wrote: Is this bug allready reported? or can somebody who has a deeper insight to this report it? I don't know. I think you should report it. If it's already reported, someone will close it as a "duplicate" -Steve I filed it. https://d.puremagic.com/issues/show_bug.cgi?id=12508 Kenji Hara
execute commands in the terminal OSX
It says in the Language Reference not to use system and gives
other options. But the other options don't seem to work. I just
have code system("clear");
Re: How do I obtain the default hash of a user-defined struct
Contents of struct are compared field by field using comparison for the type of each field. Dynamic arrays are compared by contents. If you want to compare them by pointer use .ptr property. opEquals and opCmp are not about hashing, I believe. They are just operators to help when dealing with chaining when different objects have same hash (since hash may be not unique)
Re: Sockets between D and C(++) app
It's only server. Maybe problem is on client side.
Try this if you are on Linux:
//Linux C client
#include
#include
#include
#include
#include
#include
#include
int main()
{
int sock, res;
struct sockaddr_in addr;
const char* hello;
size_t len;
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0)
{
printf("Can't create socket\n");
return -1;
}
addr.sin_family = AF_INET;
addr.sin_port = htons(5432);
addr.sin_addr.s_addr = inet_addr("127.0.0.1");
hello = "Hello from C";
len = strlen(hello);
while (1)
{
res = sendto(sock, hello, len, 0, (struct
sockaddr*)&addr, sizeof(addr));
if (res <= 0)
{
printf("Can't send\n");
return -1;
}
}
close(sock);
return 0;
}
//D server
import std.socket;
import std.stdio;
int main(string[] args)
{
auto s = new UdpSocket(AddressFamily.INET);
auto addr = new InternetAddress("127.0.0.1", 5432);
s.setOption(SocketOptionLevel.IP, SocketOption.REUSEADDR,
true);
s.bind(addr);
while (true)
{
ubyte[2048] recv_buf;
int count = s.receiveFrom(recv_buf[]);
char[] test = cast(char[])recv_buf;
writefln("Received: %s\n", test);
}
return 0;
}
Note that you don't need to remove zero-symbol if you don't pass
it from client.
Re: How to repeat a function call?
On 2014-04-02 20:48, monarch_dodra wrote: On Wednesday, 2 April 2014 at 19:54:38 UTC, monarch_dodra wrote: On Wednesday, 2 April 2014 at 19:02:29 UTC, Simen Kjærås wrote: Better ideas, please? -- Simen I only skimmed through your post, but have you tried taking a look at adjoin? Preferably, the version in head? Something like "adjoin!(repeat!(fun, N))" seems to natively do what you are asking for? I'll re-read your post later tonight, and if I'm misunderstood, I'll try to provide a better solution. Indeed, "assert(adjoin!(Repeat!(3, ()=>a++))() == tuple(0,1,2));" seems to work for me. That said, while I think the behavior is *defined*, I'm not sure it's *specified*. True, in the case of a++, it's probably a bad idea. In my case, the function is uniform(0.0, 1.0, rng), and I'm happy with it simply being random. Thanks a lot! -- Simen
Re: How do I obtain the default hash of a user-defined struct
Thanks,
Actually I'm realizing there's a lot I'm unclear about when it
comes to default comparison, equality, hashing, etc.
If my struct contains a dynamic array, are the contents of the
array compared by default, or just the pointers/lengths?
Also, when two arrays are compared for content, are their
pointers compared first in case they happen to be the same so the
deep comparison can be shortcut?
Also, how do I obtain the default hash of a dynamic array ('s
contents)? Is there one? I assume there must be since
associative arrays can take string as a key-type.
To make a struct a valid key type, do I need to implement both
opCmp and opEquals or just one or the other. It says on the page
about Associative Arrays: "The implementation may use either
opEquals or opCmp or both." Does that mean it uses whichever one
is user-defined (or both if they're both user-defined)? Or does
it mean the user is responsible for defining both?
Also, it says "Care should be taken so that the results of
opEquals and opCmp are consistent with each other when the
struct/union objects are the same or not.", certainly this means
that if a.opEquals(b), then a.opCmp(b) should be 0, but does the
converse have to be true?
Is there somewhere I can find information about default operator
implementations and consistency?
Re: How to repeat a function call?
On Wednesday, 2 April 2014 at 19:54:38 UTC, monarch_dodra wrote: On Wednesday, 2 April 2014 at 19:02:29 UTC, Simen Kjærås wrote: Better ideas, please? -- Simen I only skimmed through your post, but have you tried taking a look at adjoin? Preferably, the version in head? Something like "adjoin!(repeat!(fun, N))" seems to natively do what you are asking for? I'll re-read your post later tonight, and if I'm misunderstood, I'll try to provide a better solution. Indeed, "assert(adjoin!(Repeat!(3, ()=>a++))() == tuple(0,1,2));" seems to work for me. That said, while I think the behavior is *defined*, I'm not sure it's *specified*.
Re: How to repeat a function call?
On Wednesday, 2 April 2014 at 19:33:28 UTC, w0rp wrote:
auto initTuple(size_t N, alias func)() {
string magic() {
string result = "return tuple(";
foreach(i; 0..N) {
result ~= "func(),";
}
result ~= ");";
return result;
}
mixin(magic());
}
auto initTuple(size_t N, alias func)()
{
return mixin(q{tuple(%-(%s, %))}.format("func".repeat(N)));
}
Re: How do I obtain the default hash of a user-defined struct
On Wednesday, 2 April 2014 at 20:14:31 UTC, dnspies wrote: How can I get the default-hash of a struct I've defined (to be used as part of the hash for some containing type)? UserDefined userDefined; writeln(typeid(UserDefined).getHash(&userDefined)); Probably there is a better way. I don't like to call typeid for this purpose.
How do I obtain the default hash of a user-defined struct
How can I get the default-hash of a struct I've defined (to be used as part of the hash for some containing type)?
Re: How to repeat a function call?
On Wednesday, 2 April 2014 at 19:02:29 UTC, Simen Kjærås wrote: Better ideas, please? -- Simen I only skimmed through your post, but have you tried taking a look at adjoin? Preferably, the version in head? Something like "adjoin!(repeat!(fun, N))" seems to natively do what you are asking for? I'll re-read your post later tonight, and if I'm misunderstood, I'll try to provide a better solution.
Re: How to repeat a function call?
tuples are definitely a compile-time job. You could do something
like this to build an N tuple by calling a function N many times.
---
import std.typecons;
int foo() {
return 3;
}
auto initTuple(size_t N, alias func)() {
string magic() {
string result = "return tuple(";
foreach(i; 0..N) {
result ~= "func(),";
}
result ~= ");";
return result;
}
mixin(magic());
}
void main(string[] argv) {
enum Tuple!(int, int, int) tup = initTuple!(3, foo);
}
---
This just builds the tuple by building up a mixin string which
calls the function so many times, with no guarantees about the
order of arguments. If you have side-effects in your function
though, you probably want to move it runtime anyway and use a
range with the 'repeat' function, etc.
How to repeat a function call?
I'm trying to create a function that repeats a function call N times.
The exact use case is generating an N-dimensional tuple:
import std.typetuple;
import std.typecons;
template Repeat(size_t n, T...) {
static if (n == 1) {
alias Repeat = T;
} else static if (n) {
alias Repeat = TypeTuple!(Repeat!(n /2, T), Repeat!((n +1)/2, T));
} else {
alias Repeat = TypeTuple!();
}
}
auto fun1(size_t dim, T)(lazy T fn) {
return tuple(Repeat!(dim, fn));
}
auto fun2(size_t dim, alias fn)() {
return tuple(Repeat!(dim, fn));
}
void main() {
int a = 0;
assert(fun1!3(a++) == tuple(0,1,2));
//assert(fun2!(3, ()=>a++) == tuple(0,1,2));
}
Now, the call to fun1 works great. But I'd like to specify fn at
compile-time, thus doing something more like fun2. fun2 of course, does
not work (else why would I ask?).
I tried staticMap'ing a template that calls its parameter over the
result of Repeat in Fun2, but that did not work:
template call(alias fn) {
alias call = TypeTuple!(fn());
}
auto fun3(size_t dim, alias fn)() {
return tuple(staticMap!(call, Repeat!(dim, fn)));
}
fun3 ends up trying to evaluate the function call at compile-time, and
fails because a++ can't be executed until run-time.
Better ideas, please?
--
Simen
Re: When this will be freed?
Am 02.04.2014 17:57, schrieb Andrea Fontana:
On Wednesday, 2 April 2014 at 15:53:52 UTC, Jacob Carlborg wrote:
On 2014-04-02 17:45, Andrea Fontana wrote:
auto example(char* test) { return toStringz(to!string(test) ~ "
world!"); }
When that return string will be freed?
When there is no reference left to the string, the garbage collector
is free to collect it when it chooses to.
That's expected.
What about:
extern(C) auto example()
Same as above, extern(C) does not change how memory is collected. If
it is a C function, then it depends entirely on that particular function.
I mean: if it is an exported function (of a shared library) what
happens? There's no reference kept anywhere (in D). So if I'm right it
could be freed immediatly by GC. Right?
If you pass that string to a C function, there is a reference on the
stack. So this string will not be freed until that C-function returns.
If that C-Function returns, it is very likely however that this was the
only reference and the string will be freed the next time the garbage
collector runs.
Kind Regards
Benjamin Thaut
Re: When this will be freed?
On Wednesday, 2 April 2014 at 15:53:52 UTC, Jacob Carlborg wrote:
On 2014-04-02 17:45, Andrea Fontana wrote:
auto example(char* test) { return toStringz(to!string(test) ~
" world!"); }
When that return string will be freed?
When there is no reference left to the string, the garbage
collector is free to collect it when it chooses to.
That's expected.
What about:
extern(C) auto example()
Same as above, extern(C) does not change how memory is
collected. If it is a C function, then it depends entirely on
that particular function.
I mean: if it is an exported function (of a shared library) what
happens? There's no reference kept anywhere (in D). So if I'm
right it could be freed immediatly by GC. Right?
Re: When this will be freed?
On Wednesday, 2 April 2014 at 15:45:06 UTC, Andrea Fontana wrote:
auto example(char* test) { return toStringz(to!string(test) ~ "
world!"); }
When that return string will be freed?
What about:
extern(C) auto example()
?
to!string allocates on the GC heap when given a char* (it has to,
in order to safely produce immutable data in the string).
It will be freed by the first garbage collection ocurring after
all references to that memory are dead.
Re: When this will be freed?
On 2014-04-02 17:45, Andrea Fontana wrote:
auto example(char* test) { return toStringz(to!string(test) ~ " world!"); }
When that return string will be freed?
When there is no reference left to the string, the garbage collector is
free to collect it when it chooses to.
What about:
extern(C) auto example()
Same as above, extern(C) does not change how memory is collected. If it
is a C function, then it depends entirely on that particular function.
--
/Jacob Carlborg
When this will be freed?
auto example(char* test) { return toStringz(to!string(test) ~ "
world!"); }
When that return string will be freed?
What about:
extern(C) auto example()
?
Re: unicode console output
On 2-4-2014 15:38, Denis Mezhov wrote: On Wednesday, 2 April 2014 at 12:51:57 UTC, bearophile wrote: Denis Mezhov: How to out unicode cyrillic string to console? Try this command on the command line: chcp 65001 Bye, bearophile chcp 65001 dont'work start.bat mode con cols=150 lines=50 chcp 65001 %Path%\Minesweeper\Debug\Mi.exe don't out correct string Do you have a Unicode font selected in the dosbox properties, like Lucida Console ?
Re: unicode console output
On Wednesday, 2 April 2014 at 12:51:57 UTC, bearophile wrote: Denis Mezhov: How to out unicode cyrillic string to console? Try this command on the command line: chcp 65001 Bye, bearophile chcp 65001 dont'work start.bat mode con cols=150 lines=50 chcp 65001 %Path%\Minesweeper\Debug\Mi.exe don't out correct string
Re: core.atomic and -profile switch
Saurabh Das: I see. I wasn't sure - hence I asked. https://d.puremagic.com/issues/show_bug.cgi?id=11471 In general, how do I check if this is a known issue? Search in Bugzilla and/or ask to people. Bye, bearophile
Re: core.atomic and -profile switch
I see. I wasn't sure - hence I asked. In general, how do I check if this is a known issue? Thanks, Saurabh On Wednesday, 2 April 2014 at 11:19:16 UTC, bearophile wrote: Saurabh Das: With error: /usr/include/dmd/druntime/import/core/atomic.d(910): Error: asm statements are assumed to throw Is there a workaround for this? I have a decent sized codebase which I wish to profile for hotspots - but it won't compile with '-profile'. Isn't this a recent regression? Bye, bearophile
Re: unicode console output
On Wednesday, 2 April 2014 at 12:47:06 UTC, Denis Mezhov wrote:
I'm trying out to windows console unicode latin string
writeln("aaabbb");
console out: aaabbb
trying out to console unicode cyrillic string
writeln("бббггг");
console out: ╨│╨│╨│╨▒╨▒╨▒
How to out unicode cyrillic string to console?
-
On the website http://dlang.ru all the details are written about
re-encode the video into Cyrillic.
Re: unicode console output
Denis Mezhov: How to out unicode cyrillic string to console? Try this command on the command line: chcp 65001 Bye, bearophile
unicode console output
I'm trying out to windows console unicode latin string
writeln("aaabbb");
console out: aaabbb
trying out to console unicode cyrillic string
writeln("бббггг");
console out: ╨│╨│╨│╨▒╨▒╨▒
How to out unicode cyrillic string to console?
Re: Signature of main [was Sockets between D and C(++) app]
On Wednesday, 2 April 2014 at 08:55:23 UTC, Russel Winder wrote: The real signature of main in C/C++ is, I believe: int main(int, char**, char**) I believe in C it is: int main(void) int main(int,char**) or implementation defined (e.g. the third env pointer in the main signature from unix) But the actual entry point is system dependent and can be specified as a link option? On linux "_start" or something like that.
Re: Signature of main [was Sockets between D and C(++) app]
On 4/2/14, Dicebot wrote: > D main != C main, latter is implemented in D runtime to call the > former. 0 will be also returned by latter, not the former. Actually, the compiler injects a return statement in D's main. It generates the actual C main function (unless WinMain/DllMain is provided), which calls another special D runtime init function, which itself calls the D main function (which itself has the injected return statement unless it's already an int return). It's quite complicated, but it's all open-source so you can inspect it.
Re: Signature of main [was Sockets between D and C(++) app]
On Wednesday, 2 April 2014 at 08:55:23 UTC, Russel Winder wrote:
On Wed, 2014-04-02 at 00:34 +, bearophile wrote:
Alexandre L.:
> int main(string[] args)
> {
If you don't need args, then I suggest to not put it as main
argument. So probably this is better (note no int nor return,
in D they are not needed):
void main() {
...
}
I am not convinced by this argument. The return value (aka exit
code) is
always present, if you ignore this by having a void main, it
will return
0, i.e. main is not a void function even if you claim it is. As
for
ignoring the parameters, this is making use of the fact that
main is the
only function where you do not have to present the correct
signature.
Perhaps this exception should be removed.
The real signature of main in C/C++ is, I believe:
int main(int, char**, char**)
what is the real signature in D?
D main != C main, latter is implemented in D runtime to call the
former. 0 will be also returned by latter, not the former. Also
exception will result in >0 status code even if return type is
void. It effectively just says that you won't manage status code
manually and allows runtime to take care of it.
Re: Signature of main [was Sockets between D and C(++) app]
Russel Winder: what is the real signature in D? The _real_ signature of main() is flexible, you can use: void main() int main(in string[] args) pure nothrow D allows you to omit the args if you don't need them, returns 0 if you don't it, and it can be pure/nothrow/@safe as desired. Perhaps this exception should be removed. This special cases cause zero bugs and zero problems, so there is no chance to change this, even if we want (and I don't want). Bye, bearophile
Re: core.atomic and -profile switch
Saurabh Das: With error: /usr/include/dmd/druntime/import/core/atomic.d(910): Error: asm statements are assumed to throw Is there a workaround for this? I have a decent sized codebase which I wish to profile for hotspots - but it won't compile with '-profile'. Isn't this a recent regression? Bye, bearophile
core.atomic and -profile switch
Hello
For this test program ('test.d'):
import core.atomic;
int func1(shared int a)
{
return atomicLoad(a);
}
These invocations of dmd succeed:
1. dmd -main test.d
2. dmd -main -debug test.d
3. dmd -main -release test.d
But this one fails:
dmd -main -profile test.d
With error:
/usr/include/dmd/druntime/import/core/atomic.d(910): Error: asm
statements are assumed to throw
Is there a workaround for this? I have a decent sized codebase
which I wish to profile for hotspots - but it won't compile with
'-profile'.
Warm Regards,
Saurabh
Re: Trying Multiple Aggregate reduce
On Wednesday, 2 April 2014 at 09:25:53 UTC, Nordlöw wrote: so happens to support this. So I added your code to the test cases: Great! BTW: Why is static qualifier needed on definition of minmaxElement() in the unittest? Whenever you declare something in a nested context, it may or may not have a hidden context pointer, depending on the type, and the implementation. "static", in this context, ensures this does not happen. It's not actually *needed* in this context though. It's more of a matter of style. In your example, the function was declared in global context, so the "static" would have been gratuitous.
Re: Trying Multiple Aggregate reduce
so happens to support this. So I added your code to the test cases: Great! BTW: Why is static qualifier needed on definition of minmaxElement() in the unittest?
Re: Signature of main [was Sockets between D and C(++) app]
On Wed, 2014-04-02 at 00:34 +, bearophile wrote:
> Alexandre L.:
> > int main(string[] args)
> > {
>
> If you don't need args, then I suggest to not put it as main
> argument. So probably this is better (note no int nor return, in
> D they are not needed):
>
> void main() {
> ...
> }
I am not convinced by this argument. The return value (aka exit code) is
always present, if you ignore this by having a void main, it will return
0, i.e. main is not a void function even if you claim it is. As for
ignoring the parameters, this is making use of the fact that main is the
only function where you do not have to present the correct signature.
Perhaps this exception should be removed.
The real signature of main in C/C++ is, I believe:
int main(int, char**, char**)
what is the real signature in D?
--
Russel.
=
Dr Russel Winder t: +44 20 7585 2200 voip: sip:russel.win...@ekiga.net
41 Buckmaster Roadm: +44 7770 465 077 xmpp: rus...@winder.org.uk
London SW11 1EN, UK w: www.russel.org.uk skype: russel_winder
