Re: Help Finding Strange Memory Bug (Code linked to C library)
On Saturday, 7 December 2013 at 23:11:39 UTC, Rémy Mouëza wrote:
My strategy here would be to:
A. run the program in a debugger, say GDB, to get a exhaustive
stacktrace for hints about where to look at.
B. have a quick look at the library directly (the Use the
Source Luke strategy).
Since I was curious about your problem (you had everything
correct - this should not fail), and have no access to your
code, I checked out the shapelib code from its cvs public
repository and found out that the last pointer, `double *
padfMaxBound` is actually a pointer to an array of 4 elements:
in shapelib/shpopen.c: SHPGetInfo: starting line 823:
for( i = 0; i 4; i++ )
{
if( padfMinBound != NULL )
padfMinBound[i] = psSHP-adBoundsMin[i];
if( padfMaxBound != NULL )
padfMaxBound[i] = psSHP-adBoundsMax[i];
}
This also explains why it does not segfault when you pass a
null pointer: no array out of bounds happen then.
padfMaxBound should point to a `double []` or `double [4]`
instead of a mere `double`.
I also ended checking the API documentation
(http://shapelib.maptools.org/shp_api.html) and they do
document that padfMinBound and padfMaxbound are pointers to 4
values X, Y, Z and M in a four entry array.
You may want to check if there isn't any other of those C
tricks hiding in your D bindings.
Good catch. Now that you pointed it out I cannot for the life of
me figure out why I didn't think to check that! To make matters
worse I didn't even have to go check the CVS, because I compiled
the library from source and had all the C code sitting just a
couple of 'cd's away. For some reason it never occurred to me
that it might be expecting an array - even though one might
reasonably assume that the bounds on a multidimensional dataset
would have more than one dimension.
Thank you.
On 12/07/2013 04:29 PM, Craig Dillabaugh wrote:
Hello,
I recently wrote bindings to the C-library Shapelib (it
reads/writes a
common file format used in Geographic Information Systems).
I've been trying to write a small test program to make sure my
bindings
'work' and I've come across a bizarre memory bug. I THINK I've
identified the code that causes the problem, but I have no
idea why.
My test-suite includes this function:
void shapeRead(string filename) {
SHPHandle hShp = SHPOpen( std.string.toStringz( filename ),
rb );
int n, shp_type;
double pad_min_bound, pad_max_bound;
SHPGetInfo( hShp, n, shp_type, pad_min_bound,
pad_max_bound);
SHPClose( hShp );
}
If I comment out the SHPGetInfo call, then the segmentation
fault
doesn't happen, but if its there then the program segfaults
AFTER the
shapeRead function exits (eg. SHPClose runs fine) ).
In fact if I call SHPGetInfo as follows, the crash doesn't
occur:
SHPGetInfo( hShp, n, shp_type, pad_min_bound, null); //NULL
pointer
last arg.
So in C the function SHPGetInfo is:
void SHPAPI_CALL
SHPGetInfo( SHPHandle hSHP, int * pnEntities, int *
pnShapeType,
double * padfMinBound, double * padfMaxBound
);
While my D binding is (pretty much the same):
extern( C ) void SHPGetInfo( SHPHandle hSHP, int* pnEntities,
int* pnShapeType, double* padfMinBound, double*
padfMaxBound );
I have no idea what is going on. The sizes of ints and
doubles are 4
and 8 bytes using gcc on my system (which is how I compiled my
C
library) so those match the sizes of the corresponding D types
[I
thought maybe there was a type-size mismatch and that was
causing
something to be overwritten, but it doesn't appear that way].
Any hints on where to look next would be appreciated.
Craig
Re: Help Finding Strange Memory Bug (Code linked to C library)
On Saturday, 7 December 2013 at 23:35:49 UTC, Ali Çehreli wrote: On 12/07/2013 03:11 PM, Rémy Mouëza wrote: the last pointer, `double * padfMaxBound` is actually a pointer to an array of 4 elements: Great sleuthing! :) This thread is a good example of C's Biggest Mistake: http://www.drdobbs.com/architecture-and-design/cs-biggest-mistake/228701625 Ali If by C's Biggest Mistake you mean Craig's Biggest Mistake you are incorrect. As hard as it may be to imagine I've done even dumber things:o) It is too bad that when I do do something dumb I tend to post about it on the internet! Cheers
the Result Type
std.algorithm.splitter seems to return all its return values as a
type Result, without quotes, and i dont not seem to be able to
cast it to string[] or int[] with cast(string[]) ( or even cast
(string) - i tried that too).
I tried to use a function
void function(T, R)(T arr, out R output)
{
foreach(elem; arr)
{
output ~= elemM
}
}
i have an occasion where R is int[], and one where it is
string[]; and
but it says, that int can not be appended to string[], and string
can not be appended to int[], and compilation fails.
Nonetheless removing either of the occasions, solves it.
how to deal with this Result type?
Re: the Result Type
On 12/08/2013 12:24 AM, seany wrote:
std.algorithm.splitter seems to return all its return values as a type
Result, without quotes, and i dont not seem to be able to cast it to
string[] or int[] with cast(string[]) ( or even cast (string) - i tried
that too).
I tried to use a function
void function(T, R)(T arr, out R output)
{
foreach(elem; arr)
{
output ~= elemM
}
}
i have an occasion where R is int[], and one where it is string[]; and
but it says, that int can not be appended to string[], and string can
not be appended to int[], and compilation fails.
Nonetheless removing either of the occasions, solves it.
how to deal with this Result type?
Many other algorithms return Result, which are independent from each
other. :) (Lookup Voldemort types.)
Such types are just lazy ranges. When you eagerly need an actual array
of the elements, call std.array.array on Result:
import std.array;
import std.algorithm;
void main()
{
auto input = hello world;
auto splittedWords = input.splitter(' ').array;
static assert(is (typeof(splittedWords) == string[]));
}
Ali
Re: Equality == comparisons with floating point numbers
... I thought I did, but now I'm up against an interesting conundrum: while equality == comparison can fail here for 32-bit, isIdentical comparison can fail even for 64-bit, although only for the release-mode build. What's particularly odd is that if before calling assert(isIdentical( ... )) I use writeln to print the value of isIdentical(...) to the screen, then it prints true, and the assertion passes. If I don't have the print statement, then the assert fails. I'm presuming that calling writefln to print the variable involves it being taken off the FPU? I'm just guessing now but it seems that you are in an area that changes depending on which compiler you are using (how does it compile the FP instructions, does it use SSE instructions, how is it checking equality) and which exact processor are you on, does it support IEEE754, does the compiler try to support IEEE754 exactly? I haven't seen much in the forums about FP behaviour in e.g. dmd. E.g. how does it deal with the issues raised in http://www.cs.berkeley.edu/~wkahan/JAVAhurt.pdf? The people who know these things can found discussing them at http://forum.dlang.org/thread/khbodtjtobahhpzma...@forum.dlang.org?page=3#post-l4rj5o:24292k:241:40digitalmars.com :-). It's generally held that checking FP numbers for exact equality isn't practical and it's better to go for equality within a certain tolerance - any reason why you're not happy with that :-)?
Re: the Result Type
O_O with that knowledge, would also be possible to define new types (not aliases, but new encapsulated types) representing things such as Graph, Ring, Topology, surreal number, etc? I dont find this in your book, would you consider either adding this Volodemrot types, or in case they already are there, give me a link (both the introductions in d wiki and dr. doobs blog was very short)
Re: the Result Type
Am Sun, 08 Dec 2013 09:24:53 +0100
schrieb seany se...@uni-bonn.de:
std.algorithm.splitter seems to return all its return values as a
type Result, without quotes, and i dont not seem to be able to
cast it to string[] or int[] with cast(string[]) ( or even cast
(string) - i tried that too).
I tried to use a function
void function(T, R)(T arr, out R output)
{
foreach(elem; arr)
{
output ~= elemM
}
}
i have an occasion where R is int[], and one where it is
string[]; and
but it says, that int can not be appended to string[], and string
can not be appended to int[], and compilation fails.
Nonetheless removing either of the occasions, solves it.
how to deal with this Result type?
That confused me as a beginner as well until I understood that
these Result types are actually just structs. They are
generated at compile-time and share commonly known methods
like .front or .popFront() that identify them as ranges.
Arrays are a sub-set of ranges. The algorithms in D typically
take a range as input and a range as output. Where possible
they try not to go over the whole input at once, but only as
needed. This is called lazy evaluation and is one reason you
don't get returned a complete array. In some cases the input
might even be infinite: Try returning an array for splitter
over a random number generator as input range!
So what do you do with a Range struct? There are 3 options:
* If you really want an array you can call the function
array() on the Result:
http://dlang.org/phobos/std_array.html#.array
* If you want to further process your Result with other
algorithms, just chain them together. E.g.:
arr.splitter(abc).sort.uniq();
* If you want to iterate over the Result, foreach works on
those Result ranges:
foreach (elem; arr.splitter(abc)) {...}
The range concept makes it easy to apply any kind of algorithm
on stuff that can be represented as a consecutive items of
the same type. And it allows those algorithms to only do as
much work as needed to get the result. A good example is
http://dlang.org/phobos/std_range.html#take , which sets a
limit to the number of items to be used from the input.
So you can have an infinite random number generator, but only
take the first 50 numbers like so: randomGen.take(50);
By the way File(myfile).byLine() gives you a range over the
lines of text of myfile. That's quite handy if you have an
array of strings like a dictionary in a text file.
--
Marco
Re: File Picker
Am Sun, 08 Dec 2013 05:49:34 +0100 schrieb Malkierian rhyd...@gmail.com: On Saturday, 7 December 2013 at 23:18:18 UTC, Adam D. Ruppe wrote: On Saturday, 7 December 2013 at 23:00:00 UTC, Malkierian wrote: Is there anything in D that currently brings up a window to find and choose a file, or am I going to have to make it myself? Isn't there a built-in something or other I can hook into in Windows? Yeah, on Windows, you can just call the GetOpenFileName function (or GetSaveFileName if saving) and use the common dialog. http://msdn.microsoft.com/en-us/library/windows/desktop/ms646927(v=vs.85).aspx I wrote this quick example to show how you can use it in D: http://arsdnet.net/dcode/open.d Since the windows headers distributed with dmd are woefully incomplete, the first thing I did was copy/paste the struct and file definition from MSDN. Then, below that, is the main() function which shows how to call it. There's a lot of customization you can do there, see the Microsoft docs for more info (or search the web for any C examples, the function works the same way in D.) Man, that's great, thanks. However, I have it set up in my application, and when I first call it, I get this window: http://gyazo.com/02bc18bdc23fdf3c24aa4ff70b46be1f Then, if I cancel and open it again, I get the actual browser, but then my program freezes up: http://gyazo.com/4e5e873e57cd7a234d56c7a42198ab89 Any idea why it doesn't work the first time, but then does the second and freezes? Maybe it requires a working Windows® event loop in your application, as is typical for GUI applications on any platform. Windows typically generate all sorts of events, like mouse clicks, key strokes, resize events etc. They add up in the event queue and a white window like yours is typical of Windows® to indicate that this application is no longer working off its event loop. (Or in your case never started to do so.) If that is indeed the problem, worry not, because most events can be handled by the default handler, but you'll need to write an simple event loop. I'm not sure, but it could be that you'll need to create a dummy window as well since event loops work with window handles. Maybe it is ok to pass 0 everywhere, maybe you need a valid handle. -- Marco
Re: the Result Type
Am Sun, 08 Dec 2013 09:59:55 +0100
schrieb seany se...@uni-bonn.de:
O_O
with that knowledge, would also be possible to define new types
(not aliases, but new encapsulated types) representing things
such as Graph, Ring, Topology, surreal number, etc?
All these Result types are simply structs. Structs with
template parameters. Your question is a bit vague. You will
not be able to use D algorithms on anything but consecutive
items of the same type as I worte in my other post, if that
is the question.
Other than that the Result types are just:
struct Result(T)
{
...
}
You can call them templated struct or generic type. Many
languages offer this in some way including C++, Java, Delphi
and C#. If you have used any of those programming languages
before you are probably already familiar with the concept.
In the most simple form you can use them to create type
specialized containers, graphs or this:
struct Matrix(T, size_t width, size_t height)
if (isNumeric!T)
{
...
}
(A matrix with a fixed width and height that can be used if T
is a built-in integer or floating point type.)
--
Marco
Re: Threading methodology
Am Sat, 07 Dec 2013 17:53:06 +0100 schrieb Frustrated c1514...@drdrb.com: I have to process n arrays in some partial order. Instead of all working only on the n arrays and reusing them, [...] Wait, what partial order and how is it relevant? Who is all in all working? Why only the n arrays, I thought those are all? if I duplicate them(effectively write once read many) does that make things simpler and allow threading to be used more efficiently? Basically, instead of having to worry about threads waiting on other threads when they are writing the data I can just have each thread write to it's own duplicate array(although hopefully won't have to duplicate the buffer as that should not be necessary?). This should then make it much easier to deal because there is essentially no write contention. If I'm not mistaken this is basically the idea of TLS? (read many write once time idea so that one doesn't have to lock memory which stalls other threads in some cases and/or uses expensive locks?) The idea of TLS in D as I understand it, is that your global variables are not shared between threads by default as is the case in C. So as you point out you need not lock them since each thread has its own copy. The case I gave above is a little more simplified than the actual issue but the idea is simply that by writing to a threads own buffer reduces inter-threading issues and increases performance. One issue I have is how to combine the data back. In fact, the real case is basically n arrays. Each array is processed to create m arrays, which are processed to create l arrays and so on. Not all processing of each array takes the same time and I would like to multithread the overall processing by allowing threads to pick which (sub)arrays need processing and process them, but in their own space, and at the end send them back to the main thread. (But one thread may need access to another's buffer but only for reading so it shouldn't be a problem) This uses a lot more memory but if there are N threads and n arrays and N n, no thread will be wasted. (in my case I would have n*m*l which will almost always be larger than N so threads will always be doing something except towards the end) Another way to see the problem is to think of a digraph where each node processes all connected to it. All independent nodes must be processed first which then works itself up to the most dependent nodes. Every processed node uses a new buffer to write to instead of writing to the same buffer which locks that buffer and all other threads that may be trying to read from it(which is the key in my mind that this method is better except it requires more memory). I will of course mark nodes as being processed or not so threads don't work on unprocessed buffers and this allows dependent nodes to start up once all there dependencies become processed. Does any of this make sense? It is a little clearer now, but I didn't fully understand it yet. The sub-arrays need to be processed before the parent arrays can be completed? When does a thread need access to another thread's buffer? What if you have only 1 CPU core and there is only one thread and one buffer? Does your algorithm break? :p -- Marco
Re: the Result Type
On 12/08/2013 12:59 AM, seany wrote: I dont find this in your book, would you consider either adding this Volodemrot types, I think at least a short mention is in order. :) There are two reasons why they don't appear in the book (yet): 1) They are not a proper language feature, rather a happy discovery. (I remember Andrei's original newsgroup post about this discovery but I cannot find it at this time.) 2) They were discovered after I started writing the book. Ali
Re: the Result Type
Ali Çehreli:
When you eagerly need an actual array of the elements, call
std.array.array on Result:
import std.array;
import std.algorithm;
void main()
{
auto input = hello world;
auto splittedWords = input.splitter(' ').array;
Or just use the eager split() function.
Bye,
bearophile
Re: iterate over enum name:value pairs
Jay Norwood:
enum Suit { spades, hearts=4, diamonds=10, clubs }
foreach (i, member; EnumMembers!Suit)
Here 'i' is the index of the enumeration type tuple.
This code lacks the [] I added in my code, so your foreach is a
static one. To tell them apart when I read the code I sometimes
add a comment:
/*static*/ foreach (i, member; EnumMembers!Suit)
Bye,
bearophile
Re: Equality == comparisons with floating point numbers
On 12/08/2013 01:55 AM, Joseph Rushton Wakeling wrote: back to my original solution of approxEqual I don't know whether it helps here but just to complete the picture, there is also std.math.feqrel: http://dlang.org/phobos/std_math.html#.feqrel Ali
Re: Help Finding Strange Memory Bug (Code linked to C library)
On 12/08/2013 12:16 AM, Craig Dillabaugh wrote: I cannot for the life of me figure out why I didn't think to check that! D has already ruined your mind! :p Ali
Re: the Result Type
On Sunday, 8 December 2013 at 11:02:40 UTC, Ali Çehreli wrote: (I remember Andrei's original newsgroup post about this discovery but I cannot find it at this time.) http://www.digitalmars.com/d/archives/digitalmars/D/announce/Voldemort_Types_in_D_23511.html this?
array question
consider the follwoing:
import tango.io.Stdout, tango.io.Path, tango.text.Util;
import std.algorithm, std.string , std.stdio, std.array,
std.conv, std.regex, std.typecons;
//i know al imports are not necessary for this example, just ^c^v
from my actual code
alias string[] surSegments
void makeHashmap(T,R)(T[] plainArr, string hashes, out R[]
hashMap)
{
//first split the hashes
string [] hashesArr = std.algorithm.splitter(hashes, ',').array;
for(int i = 0; i plainArr.length; i++)
{
R hashElement;
for(int j = 0; j hashesArr.length; j++)
{
hashElement[hashesArr[j]] = = plainArr[i][j];
}
hashMap ~= hashElement;
}
}
void main()
{
surSegments[] s = [[a,b,c,d], [e,f,g,h]];
h = 1,2,3,4;
surSegments[string][] ss;
makeHashmap(s, h, ss);
}
i expect ss to look like :
[
[1 = a, 2 = b, 3 = c, 4 = d],
[1 = e, 2 = f, 3 = g, 4 = h]
]
etc.
instead i get compilation error:
Error: cannot implicitly convert expression
(hashesArr[cast(ulong)j]) of type string to string[]
isn't hashElement of type surSegment[string] and
hashElement[somestring] of type string, just like plainArr[i][j]
??
Re: Equality == comparisons with floating point numbers
On 08/12/13 12:13, Ali Çehreli wrote: I don't know whether it helps here but just to complete the picture, there is also std.math.feqrel: http://dlang.org/phobos/std_math.html#.feqrel Thanks! :-) Checking the value of feqrel followed by isIdentical looks like it might work. (OK, technically the two are telling you equivalent things, but I'd rather have built-in redundancy of the tests than revert to approxEqual.)
Running DMD tests
I'm trying my hand at a simple pesky bug in DMD. About to run test suite but must be doing something wrong. Any help would be appreciated. I followed this: http://wiki.dlang.org/Building_DMD#How_to_run_the_test_suite_in_dmd.2Ftest And here is what I get (I'm on 64-bit Ubuntu): dmitry@dmitry-VirtualBox ~/dmd2/src/dmd/test $ make MODEL=64 Creating output directory: test_results Building d_do_test tool OS: linux Running runnable tests make[1]: *** No rule to make target `test_results/runnable/A16.d.out', needed by `run_runnable_tests'. Stop. make: *** [start_runnable_tests] Error 2 dmitry@dmitry-VirtualBox ~/dmd2/src/dmd/test $ -- Dmitry Olshansky
Re: array question
On 12/08/2013 03:51 AM, seany wrote:
consider the follwoing:
import tango.io.Stdout, tango.io.Path, tango.text.Util;
import std.algorithm, std.string , std.stdio, std.array, std.conv,
std.regex, std.typecons;
//i know al imports are not necessary for this example, just ^c^v from
my actual code
alias string[] surSegments
There are the missing semicolon above and other problems with the code.
void makeHashmap(T,R)(T[] plainArr, string hashes, out R[] hashMap)
{
//first split the hashes
string [] hashesArr = std.algorithm.splitter(hashes, ',').array;
for(int i = 0; i plainArr.length; i++)
{
R hashElement;
for(int j = 0; j hashesArr.length; j++)
{
hashElement[hashesArr[j]] = = plainArr[i][j];
I think you wanted to append:
hashElement[hashesArr[j]] ~= plainArr[i][j];
What helped me see what was going on was a bunch of pragma(msg) lines:
pragma(msg, typeof(hashElement));
pragma(msg, typeof(hashesArr[j]));
pragma(msg, typeof(hashElement[hashesArr[j]]));
pragma(msg, typeof(plainArr[i][j]));
Ali
Re: the Result Type
On 12/08/2013 03:41 AM, seany wrote: On Sunday, 8 December 2013 at 11:02:40 UTC, Ali Çehreli wrote: (I remember Andrei's original newsgroup post about this discovery but I cannot find it at this time.) http://www.digitalmars.com/d/archives/digitalmars/D/announce/Voldemort_Types_in_D_23511.html this? There was an earlier newsgroup post like look what I've just discovered. Ali
Re: Unresolvable references to dlopen, dlclose etc
On 12/8/2013 6:12 AM, Mafi wrote: On Friday, 6 December 2013 at 16:54:14 UTC, Jacob Carlborg wrote: I would say that linking order shouldn't matter. But for some reason it does. This not really my area of expertise but I know that others have had the same problem. You can try and search the newsgroups for linking order related problems. So after some tweaking I made it work. Specfying the libpath with -L-L and the actual -L-l invokes gcc correctly. But the other behavior is still odd for me. I mean invoking dmd with dmd myprog.d /path/to/libSomething.a -L[Linkerflags] links with gcc myprog.o [Linkerflags] /path/to/libSomething.a [Phobos] you must dmd myprog.d -L-L/path/to/ -l-lSomething and hope the file name has the format libName.a . But why? Both are objects. Why seperate them? For me there is no reason to ever want this order! This is how the gcc linker works. It always causes confusion when people first encounter it. And even for people who have experience with it, there are corner cases where it's not always obvious that link order was the cause of an error. Google for gcc link order and you'll likely find some useful reading somewhere.
Re: array question
On Sunday, 8 December 2013 at 13:47:43 UTC, Ali Çehreli wrote:
On 12/08/2013 03:51 AM, seany wrote:
consider the follwoing:
import tango.io.Stdout, tango.io.Path, tango.text.Util;
import std.algorithm, std.string , std.stdio, std.array,
std.conv,
std.regex, std.typecons;
//i know al imports are not necessary for this example, just
^c^v from
my actual code
alias string[] surSegments
There are the missing semicolon above and other problems with
the code.
void makeHashmap(T,R)(T[] plainArr, string hashes, out R[]
hashMap)
{
//first split the hashes
string [] hashesArr = std.algorithm.splitter(hashes,
',').array;
for(int i = 0; i plainArr.length; i++)
{
R hashElement;
for(int j = 0; j hashesArr.length; j++)
{
hashElement[hashesArr[j]] = = plainArr[i][j];
I think you wanted to append:
hashElement[hashesArr[j]] ~= plainArr[i][j];
What helped me see what was going on was a bunch of pragma(msg)
lines:
pragma(msg, typeof(hashElement));
pragma(msg, typeof(hashesArr[j]));
pragma(msg, typeof(hashElement[hashesArr[j]]));
pragma(msg, typeof(plainArr[i][j]));
Ali
no i wanted to set hashElement[hashesArr[j]] = plainArr[i][j];
I realise that it had become string[][string][]
sorry my bad
Re: the Result Type
On Sun, Dec 8, 2013 at 9:59 AM, seany se...@uni-bonn.de wrote: O_O with that knowledge, would also be possible to define new types (not aliases, but new encapsulated types) representing things such as Graph, Ring, Topology, surreal number, etc? Other posters already answered your questions concerning ranges. In short, you can define internal structs (or classes, or functions) inside a function, another struct, a class, and return them. They can be parameterized on the host type template parameters, if any. All the different types in std.algorithm and std.range have *nothing* in common (no common base class, nor are they part of a common datatype), *except* they all respect the range 'concept'. As long as something (class or struct) has the three basic range methods (empty / front / popFront), it can be used with other functions in std.algorithm and std.range. Returning to you question, now. You can do exactly with other types what was done with ranges in the standard library. As long as you define the basic properties of a Graph / Ring / Whatever, and associate it with a guard template (see std.range.isInputRange), any type can be used as a Graph. Maybe you could give us more details on what you want to realize exactly?
Re: File Picker
On Sunday, 8 December 2013 at 09:17:37 UTC, Marco Leise wrote: Maybe it requires a working Windows® event loop in your application, as is typical for GUI applications on any platform. Windows typically generate all sorts of events, like mouse clicks, key strokes, resize events etc. They add up in the event queue and a white window like yours is typical of Windows® to indicate that this application is no longer working off its event loop. (Or in your case never started to do so.) If that is indeed the problem, worry not, because most events can be handled by the default handler, but you'll need to write an simple event loop. I'm not sure, but it could be that you'll need to create a dummy window as well since event loops work with window handles. Maybe it is ok to pass 0 everywhere, maybe you need a valid handle. That's rather unfortunate, as I was using DSFML as my main event generator and handler. I had a DSFML window up already that I was calling that function from. I don't know how to make the crossover between the two in D. I think I'll have to look into GtkD instead. Thanks for the idea, though.
Re: Shared library: loading doesn't call shared static this
On Sunday, 8 December 2013 at 10:31:32 UTC, Mathias LANG wrote: Thank you, and yazd, it did the trick. May I ask why I don't want to call it multiple time though ? From the sentence If the runtime was already successfully initialized this returns true., I though this was handled in some way. Or do you mean, multiple time in case of multiple libraries ? rt_term at least will [did] segfault when you call it a second time. So just don't have N shared libs each with a ctor calling rt_init and dtor calling rt_term.
Only const or immutable class thread local variables are allowed
Hello all,
I have a challenge, which is this: I'd like to have a public property which will
return a reference to an internally stored class instance.
ref MyClass myProperty() @property
{
...
}
However, this runs into a problem: I can't use static to internally store a
class instance.
I worked out a cheaty way to get around this which goes like this:
ref MyClass myProperty() @property
{
struct MyCheat
{
MyClass whatIReallyWant = new MyClass;
}
static MyCheat cheat;
// ... do other stuff ...
return cheat.whatIReallyWant;
}
... but I'm wondering if anyone has any alternative suggestions (or warnings or
caveats about the cheaty method).
Thanks best wishes,
-- Joe
Re: how to compose delegate type
On Sunday, 8 December 2013 at 00:43:51 UTC, Jesse Phillips wrote: What is wrong with the current template which returns an immutable delegate type? It still store you're immutable member function. It composes the wrong type. It composes a type that has different constness than the target type, which will likely cause problems due to transitive const. Anyways, I'm trying to find a workaround to https://d.puremagic.com/issues/show_bug.cgi?id=11694
Re: File Picker
On Sunday, 8 December 2013 at 04:49:35 UTC, Malkierian wrote: Any idea why it doesn't work the first time, but then does the second and freezes? Could be a missing argument to the function, I did a quick test on Windows XP and it looks like you're on Vista. Later today, I'll be on my other Windows computer and I'll try it there and see what's going on.
Re: iterate over enum name:value pairs
I see comments about enums being somehow implemented as tuples,
and comments about tuples somehow being implemented as structs,
but I couldn't find examples of static initialization of arrays
of either.
Finally after playing around with it for a while, it appears this
example below works for static array of struct initialization.
It also doesn't display the enum bug of hearts2 coming back as
hearts in the iteration.
I tried C static array of struct initialization syntax, and it
didn't work, which kind of surprises me.
module main;
import std.stdio;
void main()
{
struct Suit {string nm; int val;};
static Suit[5] suits = [
Suit(spades,1),
Suit(hearts,4),
Suit(hearts2,4),
Suit(diamonds,10),
Suit(clubs,11)
];
foreach (member; suits)
{
writefln(%s: %d, member.nm, member.val);
}
}
D:\dprojects\ConsoleApp1\ConsoleApp1dmd -run main.d
spades: 1
hearts: 4
hearts2: 4
diamonds: 10
clubs: 11
Re: iterate over enum name:value pairs
Jay Norwood:
I see comments about enums being somehow implemented as tuples,
Enums are usually implemented as ints, unless you specify a
different type.
and comments about tuples somehow being implemented as structs,
Phobos Tuples are implemented with structs.
but I couldn't find examples of static initialization of arrays
of either.
Here it is:
import std.typecons;
enum Foo { A, B, C }
Foo[] a1 = [Foo.A, Foo.B];
alias T = Tuple!(int, int);
T[] a1 = [T(1, 2), T(3, 4)];
void main() {}
It also doesn't display the enum bug of hearts2 coming back as
hearts in the iteration.
Because those are different strings.
I tried C static array of struct initialization syntax, and it
didn't work, which kind of surprises me.
Here it is:
void main() {
static struct Suit { string nm; int val; }
static Suit[5] suits = [
{spades, 1},
{hearts, 4}];
}
Bye,
bearophile
Re: Only const or immutable class thread local variables are allowed
On 12/08/2013 10:00 AM, Joseph Rushton Wakeling wrote:
I have a challenge, which is this: I'd like to have a public property
which will return a reference to an internally stored class instance.
ref MyClass myProperty() @property
{
...
}
First, the usual question: Since class varibles are already references,
do you really need to return ref?
In any case, I think class static this is the solution:
class MyClass
{
static MyClass whatIReallyWant;
static this()
{
whatIReallyWant = new MyClass;
}
/* ref */ MyClass myProperty() @property
{
return whatIReallyWant;
}
}
void main()
{
auto m = new MyClass;
auto s = m.myProperty;
}
Ali
Re: iterate over enum name:value pairs
Yes, thanks, that syntax does work for the initialization.
The C syntax that failed for me was using the curly brace form
shown in the following link.
http://www.c4learn.com/c-programming/c-initializing-array-of-structure/
Also, I think I was trying forms of defining the struct and
initializing the array in the same line... something like this C:
static struct Suit{ int i; long lv;} suits[3] = {{1, 2L},{2,
4L},{3,9L}};
It looks to me like D requires a named struct definition in a
separate line from the array definition. If that is so, then
the C initialization of an array with an unnamed struct type,
like this, would require a struct type name.
static struct { int i; long lv;} suits[3] = {{1, 2L},{2,
4L},{3,9L}};
So, from your static intialization example, this works.
Also, the conversion of struct to tuple makes the writefln
tupleof conversion on the struct a little cleaner, since you only
have to specify the single tuple parameter.
module main;
import std.stdio;
void main()
{
struct Suit {string nm; int val; int val2; string shortNm;};
static Suit[5] suits = [
{spades,1,6,spd},
{hearts,4,10,hrt},
{hearts2,4,10,hrt2},
{diamonds,10,16,dmd},
{clubs,11,17,clb}
];
foreach (member; suits)
{
auto tup = member.tupleof;
writefln(%s %d %d %s, tup);
}
}
prints
spades 1 6 spd
hearts 4 10 hrt
hearts2 4 10 hrt2
diamonds 10 16 dmd
clubs 11 17 clb
I also tried using writefln(tup) and writeln(tup) in the example
above. The output from writeln(tup) looks like it is headed in
the right direction. Maybe a writecsv(tup) would be useful.
spades16spd
hearts410hrt
hearts2410hrt2
diamonds1016dmd
clubs1117clb
Re: Only const or immutable class thread local variables are allowed
On 08/12/13 21:12, Ali Çehreli wrote: In any case, I think class static this is the solution: I think I may have misled you by talking about properties, because I _don't_ mean a property of a class. I mean a public standalone function that is marked as a @property, which returns a persistent instance of some class. The actual motivation is reimplementing std.random.rndGen but with class-based RNGs instead of structs :-) A consequence of this is that I don't think a static class instance can work, because the returned class has to be non-const -- it's an RNG that will be updated!
Re: File Picker
Hmm, I just tried from my Windows 7 computer and it worked. If you do my sample program without changes http://arsdnet.net/dcode/open.d does it work, or is the problem after copy/pasting it into the rest of your program? Also are you compiling 64 bit? I only tried 32 bit since my laptop has a 32 bit processor so that could be a problem too.
Re: iterate over enum name:value pairs
Jay Norwood:
If that is so, then the C initialization of an array with an
unnamed struct type, like this, would require a struct type
name.
static struct { int i; long lv;} suits[3] = {{1, 2L},{2,
4L},{3,9L}};
Giving a struct a name is often a good idea. But if you don't
want to name it, then you can use a Phobos Tuple. You can even
omit its field names if you want.
struct Suit {string nm; int val; int val2; string shortNm;};
Better:
static struct Suit {string nm; int val; int val2; string
shortNm;}
Generally inside functions it's better to define static struct.
And struct definitions don't need a trailing semicolon.
foreach (member; suits)
Generally it's better to attach an 'immutable' there, this is not
always possible, but it's a good habit:
foreach (immutable member; suits)
I also tried using writefln(tup) and writeln(tup) in the
example above. The output from writeln(tup) looks like it is
headed in the right direction. Maybe a writecsv(tup) would be
useful.
Try:
member.writeln;
Bye,
bearophile
Re: Only const or immutable class thread local variables are allowed
On Sunday, 8 December 2013 at 21:32:35 UTC, Joseph Rushton Wakeling wrote: On 08/12/13 21:12, Ali Çehreli wrote: In any case, I think class static this is the solution: I think I may have misled you by talking about properties, because I _don't_ mean a property of a class. I mean a public standalone function that is marked as a @property, which returns a persistent instance of some class. The actual motivation is reimplementing std.random.rndGen but with class-based RNGs instead of structs :-) A consequence of this is that I don't think a static class instance can work, because the returned class has to be non-const -- it's an RNG that will be updated! I understand you are talking about the Singleton design pattern. You might want to look how std.parallelism does it with the default global thread pool. https://github.com/D-Programming-Language/phobos/blob/master/std/parallelism.d#L3261
Re: iterate over enum name:value pairs
foreach (immutable member; suits) Sometimes you have to use: foreach (const member; suits) Bye, bearophile
Re: File Picker
On Sunday, 8 December 2013 at 22:26:11 UTC, Adam D. Ruppe wrote: Hmm, I just tried from my Windows 7 computer and it worked. If you do my sample program without changes http://arsdnet.net/dcode/open.d does it work, or is the problem after copy/pasting it into the rest of your program? Also are you compiling 64 bit? I only tried 32 bit since my laptop has a 32 bit processor so that could be a problem too. No, I'm not building in 64bit. However, I just tried it, copy paste into my main, no additional libs or includes, only main.d compiling. Still get a window like that first image, and if I put another one in after it, it does the same not responding issue.
Re: File Picker
On Sunday, 8 December 2013 at 23:17:46 UTC, Malkierian wrote: On Sunday, 8 December 2013 at 22:26:11 UTC, Adam D. Ruppe wrote: Hmm, I just tried from my Windows 7 computer and it worked. If you do my sample program without changes http://arsdnet.net/dcode/open.d does it work, or is the problem after copy/pasting it into the rest of your program? Also are you compiling 64 bit? I only tried 32 bit since my laptop has a 32 bit processor so that could be a problem too. No, I'm not building in 64bit. However, I just tried it, copy paste into my main, no additional libs or includes, only main.d compiling. Still get a window like that first image, and if I put another one in after it, it does the same not responding issue. I am working in Xamarin, though, if that makes a difference.
Re: iterate over enum name:value pairs
On Sunday, 8 December 2013 at 22:30:25 UTC, bearophile wrote:
Try:
member.writeln;
Bye,
bearophile
yeah, that's pretty nice.
module main;
import std.stdio;
void main()
{
struct Suit {string nm; int val; int val2; string shortNm;};
static Suit[5] suits = [
{spades,1,6,spd},
{hearts,4,10,hrt},
{hearts2,4,10,hrt2},
{diamonds,10,16,dmd},
{clubs,11,17,clb}
];
foreach (immutable member; suits)
{
member.writeln();
}
}
output:
immutable(Suit)(spades, 1, 6, spd)
immutable(Suit)(hearts, 4, 10, hrt)
immutable(Suit)(hearts2, 4, 10, hrt2)
immutable(Suit)(diamonds, 10, 16, dmd)
immutable(Suit)(clubs, 11, 17, clb)
Re: File Picker
On Sunday, 8 December 2013 at 23:32:54 UTC, Malkierian wrote: On Sunday, 8 December 2013 at 23:17:46 UTC, Malkierian wrote: On Sunday, 8 December 2013 at 22:26:11 UTC, Adam D. Ruppe wrote: Hmm, I just tried from my Windows 7 computer and it worked. If you do my sample program without changes http://arsdnet.net/dcode/open.d does it work, or is the problem after copy/pasting it into the rest of your program? Also are you compiling 64 bit? I only tried 32 bit since my laptop has a 32 bit processor so that could be a problem too. No, I'm not building in 64bit. However, I just tried it, copy paste into my main, no additional libs or includes, only main.d compiling. Still get a window like that first image, and if I put another one in after it, it does the same not responding issue. I am working in Xamarin, though, if that makes a difference. I just tested it myself building in Xamarin. Worked like it is supposed to, so I'm not sure what's up. I'm running Win7 though. When I get home I can see if running this along side DSFML's event stuff is a problem, but I hope it isn't something specific to your computer. That would blow.
Re: iterate over enum name:value pairs
static Suit[5] suits = [
{spades,1,6,spd},
{hearts,4,10,hrt},
{hearts2,4,10,hrt2},
{diamonds,10,16,dmd},
{clubs,11,17,clb}
Also, in D it's better to put a space after every comma, to
increase readability a little:
static immutable Suit[5] suits = [
{spades, 1, 6, spd},
Bye,
bearophile
Re: iterate over enum name:value pairs
Jay Norwood:
struct Suit {string nm; int val; int val2; string shortNm;};
You have missed my suggestions above regarding the struct :-)
Look at this:
void main() {
int x;
struct Foo1 {
int bar1() { return x; }
}
pragma(msg, Foo1.sizeof);
static struct Foo2 {
// this gives an error
int bar2() { return x; }
}
pragma(msg, Foo2.sizeof);
}
bar2() gives an error because it can't access x. If you comment
out the bar2 line, the output is:
4u
1u
Usually you don't want your struct defined inside a function to
contain a pointer to the enclosing function.
static Suit[5] suits = [
{spades,1,6,spd},
{hearts,4,10,hrt},
{hearts2,4,10,hrt2},
{diamonds,10,16,dmd},
{clubs,11,17,clb}
];
Unless you have to mutate the contents of a variable, like your
suits, define it const or immutable:
static immutable Suit[5] suits = [
{spades,1,6,spd},
...
];
Generally in D add const/immutable to all variables that you
don't need to mutate, if/where you can.
Bye,
bearophile
Re: iterate over enum name:value pairs
It looks like the writeln() does a pretty good job, even for enum
names.
I also saw a prettyprint example that prints the structure member
name, and compared its output.
http://forum.dlang.org/thread/ip23ld$93u$1...@digitalmars.com
module main;
import std.stdio;
import std.traits;
void main()
{
enum Suit { spades, hearts=4, diamonds=10, clubs }
enum SuitShort { spd, hrt=4, dmd=10, clb }
static struct Suits { Suit nm; int val; int val2; SuitShort
shortNm;}
static Suits[] suits = [
{Suit.spades, 1, 6, SuitShort.spd},
{Suit.hearts, 4, 10, SuitShort.hrt},
{Suit.diamonds, 4, 10, SuitShort.dmd},
{Suit.clubs, 10, 16, SuitShort.clb}
];
foreach (immutable member; suits)
{
auto fields = __traits(allMembers, typeof(member));
auto values = member.tupleof;
foreach (index, value; values)
{
writef(%s=%s, , fields[index], value);
}
writeln();
member.writeln();
}
}
output:
nm=spades, val=1, val2=6, shortNm=spd,
immutable(Suits)(spades, 1, 6, spd)
nm=hearts, val=4, val2=10, shortNm=hrt,
immutable(Suits)(hearts, 4, 10, hrt)
nm=diamonds, val=4, val2=10, shortNm=dmd,
immutable(Suits)(diamonds, 4, 10, dmd)
nm=clubs, val=10, val2=16, shortNm=clb,
immutable(Suits)(clubs, 10, 16, clb)
Re: iterate over enum name:value pairs
Jay Norwood:
Using enums, despite their problems, if often better than strings.
static Suits[] suits = [
{Suit.spades, 1, 6, SuitShort.spd},
{Suit.hearts, 4, 10, SuitShort.hrt},
{Suit.diamonds, 4, 10, SuitShort.dmd},
{Suit.clubs, 10, 16, SuitShort.clb}
];
foreach (immutable member; suits)
In some cases you can also use with() to avoid struct/enum name
repetitions (unfortunately it creates a scope, so if you define
an immutable variable inside it, it will be invisible and
destroyed once the with() scope ends. This reduces the usefulness
of with()).
with (Suit) with (SuitShort)
{
static Suits[] suits = [
{spades,1, 6, spd},
{hearts,4, 10, hrt},
{diamonds, 4, 10, dmd},
{clubs,10, 16, clb}
];
foreach (immutable member; suits)
...
Bye,
bearophile
regarding Latin1 to UTF8 encoding
Hi, I am having some problems trygin to pass regular expressions to a webpage encoded in Latin1. I have unsuccessfully tried to convert it to UTF8 before passing the regular expression. Initially I tried to do something like this: auto input = readText(myfile.htm); auto output = replace(input, re1, re2); But I got this error when trying to run the application: std.utf.UTFException@C:\DMD2\Windows\bin\..\..\src\phobos\std\utf.d(1113): Invalid UTF-8 sequence (at index 1) I then tried this, but the error remains auto input = readText(myfile.htm); string buffer; transcode(input, buffer); auto output = replace(buffer, re1, re2); Also, this did not work: auto input = cast(string) read(myfile.htm); string buffer; transcode(input, buffer); auto output = replace(buffer, re1, re2); core.exception.AssertError@std.encoding(1995): Assertion failure Please, any help would be appreciated. Regards, Hugo
Re: regarding Latin1 to UTF8 encoding
On Monday, 9 December 2013 at 02:40:29 UTC, Hugo Florentino wrote: auto input = readText(myfile.htm); Don't use readText if it isn't utf-8; readtext assumes it is utf 8. I've never actually used std.encoding (I wrote my own encoding module for my dom.d, which I used for website scraping too) but I think this is what you want: Latin1String input = cast(Latin1String) std.file.read(myfile.htm); string buffer; transcode(input, buffer); auto output = replace(buffer, re1, re2); see if that works
Re: File Picker
I wonder if your other DSFML thingy use threads or something... the GetOpenFileName function blocks until the user makes their choice. So that could be stalling the SFML event loop, or maybe having threading issues. I don't know. But I get the feeling that the problem is one of these two things.
Modify const reference data
[DMD 2.064.2]
Hello,
I've been strugling with a solution before bothering you guys
here (again). I have my own complex code but i made a VERY simple
test case to reproduce my problem, here's the code:
private import std.stdio;
class A
{
private const ubyte* data;
private ubyte[] abc;
this()
{
abc = [1,2,3,4];
data = cast(const ubyte*)abc.ptr;
}
public void print()
{
for(size_t i = 0; i 4; i++)
{
writefln(%d, data[i]);
}
}
}
class B
{
private const ubyte* data;
private ubyte[] abc;
this()
{
data = cast(const ubyte*)abc.ptr;
}
public void foo()
{
abc = [1,2,3,4];
}
public void print()
{
for(size_t i = 0; i 4; i++)
{
writefln(%d, data[i]);
}
}
}
void main()
{
A a = new A();
a.print(); // OK.
B b = new B();
b.print(); // Crash.
}
The thing is that i can not use the data that const variable
data in class B is referencing because in my original code i
get Invalid Memory Operation, in the test case i get access
violation but it doesn't matter the name of the exception, the
only thing that matters is that the exception raises for the same
reason. I understand that i should not modify the const data
outside a constructor but by stricts reason i can't avoid that.
Do you guys have any other aproach to get away with this? (modify
a const reference data and then manipulate that data). THANK YOU
very much in advance. D2 learner by the way.
Re: Modify const reference data
Duhhh! i got the pink avatar by default. That sucks. Pink is just not my color.
Re: regarding Latin1 to UTF8 encoding
On Mon, 09 Dec 2013 03:44:19 +0100, Adam D. Ruppe wrote: On Monday, 9 December 2013 at 02:40:29 UTC, Hugo Florentino wrote: auto input = readText(myfile.htm); Don't use readText if it isn't utf-8; readtext assumes it is utf 8. I've never actually used std.encoding (I wrote my own encoding module for my dom.d, which I used for website scraping too) but I think this is what you want: Latin1String input = cast(Latin1String) std.file.read(myfile.htm); string buffer; transcode(input, buffer); auto output = replace(buffer, re1, re2); see if that works Actually, it did work, even keeping input type as auto. It seems the explicit typecast to Lating1String was the required element for it to work, which makes sense now that I think about it. Thanks a lot for the (amazingly quick) reply ;) Now, if I may add a closely related doubt: Suppose myfile.txt was given to me daily by careless people who usually save it as Latin1 but from time to time might save it as UTF8. Is there a way to detect the encoding prior to typecasting/loading the file? Regards, Hugo
Re: regarding Latin1 to UTF8 encoding
On Monday, 9 December 2013 at 03:07:58 UTC, Hugo Florentino wrote:
Is there a way to detect the encoding prior to
typecasting/loading the file?
UTF-8 can be detected fairly reliably, but not much luck for
other encodings. A Windows-1258 and a Latin1 file, for example,
are usually fairly indistinguishable from a binary perspective -
they use the same numbers, just for different things.
(It is possible to distinguish them if you use some context and
grammar check kind of things, but that's not easy.)
But utf-8 has a neat feature: any non-ascii stuff needs to
validate, and it is unlikely that random data would correctly
validate.
std.utf.validate can do that (though it throws an exception if it
fails, ugh!)
So here's how I did it in my own characterencodings.d:
https://github.com/adamdruppe/misc-stuff-including-D-programming-language-web-stuff/blob/master/characterencodings.d#L138
string utf8string;
import std.utf;
try {
validate!string(cast(string) rawdata);
// validation passed, assume it is UTF-8 and use
it
utf8string = cast(string) rawdata;
} catch(UTFException t) {
// not utf-8, try latin1
transcode(cast(Latin1String) rawData, utf8string);
}
// now go ahead and use utf8 string, it should be set
Re: Modify const reference data
Easy problem in class B: data is null!
On Monday, 9 December 2013 at 02:53:01 UTC, Heinz wrote:
class B
{
private const ubyte* data;
private ubyte[] abc;
this()
{
data = cast(const ubyte*)abc.ptr;
}
Since abc isn't initialized in this constructor, abc.ptr is null.
So data is null too.
public void print()
{
for(size_t i = 0; i 4; i++)
{
writefln(%d, data[i]);
}
}
}
And since data is null, data[i] will be a memory
err/segfault/access violation/whatever it is called.
Re: regarding Latin1 to UTF8 encoding
On Mon, 09 Dec 2013 04:19:51 +0100, Adam D. Ruppe wrote:
On Monday, 9 December 2013 at 03:07:58 UTC, Hugo Florentino wrote:
Is there a way to detect the encoding prior to typecasting/loading
the file?
UTF-8 can be detected fairly reliably, but not much luck for other
encodings. A Windows-1258 and a Latin1 file, for example, are usually
fairly indistinguishable from a binary perspective - they use the
same
numbers, just for different things.
(It is possible to distinguish them if you use some context and
grammar check kind of things, but that's not easy.)
But utf-8 has a neat feature: any non-ascii stuff needs to validate,
and it is unlikely that random data would correctly validate.
std.utf.validate can do that (though it throws an exception if it
fails, ugh!)
So here's how I did it in my own characterencodings.d:
https://github.com/adamdruppe/misc-stuff-including-D-programming-language-web-stuff/blob/master/characterencodings.d#L138
string utf8string;
import std.utf;
try {
validate!string(cast(string) rawdata);
// validation passed, assume it is UTF-8 and use it
utf8string = cast(string) rawdata;
} catch(UTFException t) {
// not utf-8, try latin1
transcode(cast(Latin1String) rawData, utf8string);
}
// now go ahead and use utf8 string, it should be set
Clever solution, thanks.
Coud this work using scope instead of try/catch?
P.S. Nice unit, by the way.
Re: regarding Latin1 to UTF8 encoding
On Monday, 9 December 2013 at 03:33:46 UTC, Hugo Florentino wrote: Coud this work using scope instead of try/catch? Maybe, but I don't think it would be very pretty. Really, I think validate should return a bool instead of throwing, but since it doesn't the try/catch is as close as it gets. P.S. Nice unit, by the way. BTW if you need to parse random html, grab that file and my dom.d from the same repo. auto document = new Document(); document.parseGarbage(whatever_data); parseGarbage tries to determine the character encoding automatically, from the validate check or the meta tags in the HTML if they are there, then guessing if not. It is pretty good at parsing broken html tag soup to make a dom similar to the browser. Then you can get data out of it doing things like auto firstParagraph = document.querySelector(p:first-child); if(firstParagraph is null) writeln(no first child paragraph); else writeln(first child paragraph text: , firstParagraph.innerText); and stuff like that, if you have used Javascript before dom.d should look fairly familiar.
Re: iterate over enum name:value pairs
Thanks. That's looking pretty clean.
I had already tried the shorter enum names without using the with
statement, and it failed to compile. I thought it might work
since the struct definition already specifies the enum type for
the two members.
with (Suit) with (SuitShort)
{
static Suits[] suits = [
{spades,1, 6, spd},
{hearts,4, 10, hrt},
{diamonds, 4, 10, dmd},
{clubs,10, 16, clb}
];
foreach (immutable member; suits)
...
Bye,
bearophile
Re: File Picker
On Monday, 9 December 2013 at 02:45:48 UTC, Adam D. Ruppe wrote: I wonder if your other DSFML thingy use threads or something... the GetOpenFileName function blocks until the user makes their choice. So that could be stalling the SFML event loop, or maybe having threading issues. I don't know. But I get the feeling that the problem is one of these two things. Yes, but like I said, I took DSFML completely out of the project to do a test compile using only main.d and not linking any external libs (DSFML, GtkD, or DerelictAL). No special build instructions or anything in Xamarin, but the first time it's called, I get that first picture and the second time (after clicking cancel on the first one it's opened again in the code), it shows the proper file structure and freezes. In my regular setup (not the main.d exclusive test), my program would continue to work just fine until I called the file chooser a second time.
Re: iterate over enum name:value pairs
I notice that if Suit and SuitShort have an enum with the same
name, then you still have to fully qualify the enum names when
using the with statement. So, for example, if spd in SuitShort
was renamed spades, the first entry in the array initialization
would have to be {Suit.spades, 1, 6, SuitShort.spades}.
with (Suit) with (SuitShort)
{
static Suits[] suits = [
{spades,1, 6, spd},
{hearts,4, 10, hrt},
{diamonds, 4, 10, dmd},
{clubs,10, 16, clb}
];
foreach (immutable member; suits)
...
Bye,
bearophile
Re: Modify const reference data
On 12/08/2013 07:24 PM, Adam D. Ruppe wrote:
Easy problem in class B: data is null!
On Monday, 9 December 2013 at 02:53:01 UTC, Heinz wrote:
class B
{
private const ubyte* data;
private ubyte[] abc;
this()
{
data = cast(const ubyte*)abc.ptr;
}
Since abc isn't initialized in this constructor, abc.ptr is null. So
data is null too.
public void print()
{
for(size_t i = 0; i 4; i++)
{
writefln(%d, data[i]);
}
}
}
And since data is null, data[i] will be a memory err/segfault/access
violation/whatever it is called.
Apparently the OP intended to set it in foo(). If the data is actually
mutable and there really is no way other than going against the type
system, foo() must be called at least once and can be implemented like this:
public void foo()
{
abc = [1,2,3,4];
cast(ubyte*)data = abc.ptr;
}
// ...
B b = new B();
b.foo();
b.print(); // now OK
Ali
Compile error using synchronized in ldc (but not dmd)
Hello,
The following code snippet fails to compile on ldc2 (0.12.1), but
successfully compiles on dmd 2.064.2 :
struct Particle {
double x,y,z,w,x2;
this(double[] arr) {
x = arr[0]; y = arr[1]; z=arr[2]; w=arr[3];
x2 = x*x + y*y + z*z;
}
}
synchronized class SyncArray {
private Particle[] buf;
void push(Particle[] arr1) {
buf.length = arr1.length;
buf[] = arr1[];
}
Particle[] pop() {
auto _tmp = new Particle[buf.length];
_tmp[] = buf[];
buf = null;
return _tmp;
}
}
The error message in ldc2 :
test.d(14): Error: cannot implicitly convert expression (arr1[])
of type Particle[] to const(shared(Particle)[])
test.d(19): Error: cannot implicitly convert expression
(this.buf[]) of type shared(Particle)[] to const(Particle[])
What am I doing wrong here?
Thanks in advance!
-- Nikhil
P.S. I've been enjoying coding in D a lot -- many thanks to the
entire D community!
Re: File Picker
On Monday, 9 December 2013 at 04:01:54 UTC, Malkierian wrote: On Monday, 9 December 2013 at 02:45:48 UTC, Adam D. Ruppe wrote: I wonder if your other DSFML thingy use threads or something... the GetOpenFileName function blocks until the user makes their choice. So that could be stalling the SFML event loop, or maybe having threading issues. I don't know. But I get the feeling that the problem is one of these two things. Yes, but like I said, I took DSFML completely out of the project to do a test compile using only main.d and not linking any external libs (DSFML, GtkD, or DerelictAL). No special build instructions or anything in Xamarin, but the first time it's called, I get that first picture and the second time (after clicking cancel on the first one it's opened again in the code), it shows the proper file structure and freezes. In my regular setup (not the main.d exclusive test), my program would continue to work just fine until I called the file chooser a second time. What version(s) of dmd are you using?
Re: Compile error using synchronized in ldc (but not dmd)
Just a quick follow-up : replacing the array operation by a
foreach works around this issue, but I don't understand why it
failed in the first place.
On Monday, 9 December 2013 at 04:26:01 UTC, Nikhil Padmanabhan
wrote:
Hello,
The following code snippet fails to compile on ldc2 (0.12.1),
but successfully compiles on dmd 2.064.2 :
struct Particle {
double x,y,z,w,x2;
this(double[] arr) {
x = arr[0]; y = arr[1]; z=arr[2]; w=arr[3];
x2 = x*x + y*y + z*z;
}
}
synchronized class SyncArray {
private Particle[] buf;
void push(Particle[] arr1) {
buf.length = arr1.length;
buf[] = arr1[];
}
Particle[] pop() {
auto _tmp = new Particle[buf.length];
_tmp[] = buf[];
buf = null;
return _tmp;
}
}
The error message in ldc2 :
test.d(14): Error: cannot implicitly convert expression
(arr1[]) of type Particle[] to const(shared(Particle)[])
test.d(19): Error: cannot implicitly convert expression
(this.buf[]) of type shared(Particle)[] to const(Particle[])
What am I doing wrong here?
Thanks in advance!
-- Nikhil
P.S. I've been enjoying coding in D a lot -- many thanks to the
entire D community!
Re: File Picker
On Monday, 9 December 2013 at 04:52:21 UTC, Malkierian wrote: On Monday, 9 December 2013 at 04:01:54 UTC, Malkierian wrote: On Monday, 9 December 2013 at 02:45:48 UTC, Adam D. Ruppe wrote: I wonder if your other DSFML thingy use threads or something... the GetOpenFileName function blocks until the user makes their choice. So that could be stalling the SFML event loop, or maybe having threading issues. I don't know. But I get the feeling that the problem is one of these two things. Yes, but like I said, I took DSFML completely out of the project to do a test compile using only main.d and not linking any external libs (DSFML, GtkD, or DerelictAL). No special build instructions or anything in Xamarin, but the first time it's called, I get that first picture and the second time (after clicking cancel on the first one it's opened again in the code), it shows the proper file structure and freezes. In my regular setup (not the main.d exclusive test), my program would continue to work just fine until I called the file chooser a second time. What version(s) of dmd are you using? I used 2.064.2, and it worked for me. I know you recently upgraded though. Maybe you could try uninstalling and then reinstalling the compiler?
Re: File Picker
On Monday, 9 December 2013 at 05:09:42 UTC, Jeremy DeHaan wrote: On Monday, 9 December 2013 at 04:52:21 UTC, Malkierian wrote: On Monday, 9 December 2013 at 04:01:54 UTC, Malkierian wrote: On Monday, 9 December 2013 at 02:45:48 UTC, Adam D. Ruppe wrote: I wonder if your other DSFML thingy use threads or something... the GetOpenFileName function blocks until the user makes their choice. So that could be stalling the SFML event loop, or maybe having threading issues. I don't know. But I get the feeling that the problem is one of these two things. Yes, but like I said, I took DSFML completely out of the project to do a test compile using only main.d and not linking any external libs (DSFML, GtkD, or DerelictAL). No special build instructions or anything in Xamarin, but the first time it's called, I get that first picture and the second time (after clicking cancel on the first one it's opened again in the code), it shows the proper file structure and freezes. In my regular setup (not the main.d exclusive test), my program would continue to work just fine until I called the file chooser a second time. What version(s) of dmd are you using? I used 2.064.2, and it worked for me. I know you recently upgraded though. Maybe you could try uninstalling and then reinstalling the compiler? *sigh* No dice. And I can't get GtkD to work either, because of entry point errors...
Re: Only const or immutable class thread local variables are allowed
On 09/12/13 01:24, Ali Çehreli wrote: On 12/08/2013 02:40 PM, qznc wrote: I understand you are talking about the Singleton design pattern. You might want to look how std.parallelism does it with the default global thread pool. https://github.com/D-Programming-Language/phobos/blob/master/std/parallelism.d#L3261 David Simcha presented it as a D-specific pattern and explained how D avoids at least one of the bugs of double-checked locking: (i) That's very cool :-D (ii) I still think it's not what I want. The static class instance doesn't need to be globally global, I want the default thread-local storage as per the existing std.random.rndGen. Hence the solution I arrived at, but which I'm sure could be improved.
Simultaneous Assignment
Does D has somtething similar ?
http://code.google.com/p/go-wiki/wiki/SimultaneousAssignment
I tried this way, but it not worked out.
if((int x = 10) 0) {
writefln(x is %s, x);
}
