Re: nogc Array
On Tuesday, 26 January 2016 at 03:06:40 UTC, maik klein wrote:
On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
Is there a GC-less array that we can use out of the box or do
I have to create my own?
https://dlang.org/phobos/std_container_array.html
How do we use std.algorithm with it? I could like to use find but
I have no luck.
I have
std.container.array!MyClass classes;
then std.algorithm.find!("a.myInt == b")(classes, 3)
I was hoping this would find the first object in classes who has
myInt == 3 but I just get many errors about not being able to
find the right definition.
I guess std.container.array isn't a range? Or am I using it wrong?
Re: how to allocate class without gc?
On Tuesday, 26 January 2016 at 01:09:50 UTC, Igor wrote: Is there any examples that shows how to properly allocate an object of a class type with the new allocators and then release it when desired? Allocate a block of memory big enough to hold an instance of your class using whichever allocator you need, then instantiate a class instance with std.conv.emplace. http://p0nce.github.io/d-idioms/#Placement-new-with-emplace
Re: how to allocate class without gc?
On 01/25/2016 09:47 PM, Igor wrote: > it fails because the string representing the name inside App is null... > Which doesn't happen when I use new. There must be something else going on. Do you see it with a simpler type? > Should it work as expected(which it isn't) new allocates and constructs, emplace does not allocate and construct. That shold be the only difference. > or do I have to also emplace all the fields and such so they are not for > some reason released? Not at all. Ali
Re: How can i track the GC when it's runing?
On Monday, 25 January 2016 at 09:33:15 UTC, Dsby wrote: I want to know How can i track the GC when it's runing? And Which algorithm is D's GC used,only Scan-Mark? Something that isn't on Garry's link: if using dmd you can pass the "-profile=gc" flag which will do the GC configuration so that you get a summary of all allocations at the end of the program.
Re: nogc Array
On Tuesday, 26 January 2016 at 04:38:13 UTC, Adam D. Ruppe wrote:
On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
then std.algorithm.find!("a.myInt == b")(classes, 3)
Try
std.algorithm.find!("a.myInt == b")(classes[], 3)
notice the [] after classes
I guess std.container.array isn't a range? Or am I using it
wrong?
Containers aren't really ranges, they instead *offer* ranges
that iterate over them. Built in arrays are a bit special in
that they do this implicitly so the line is more blurred there,
but it is a general rule that you need to get a range out of a
container.
Otherwise, consider that iterating over it with popFront would
result in the container being automatically emptied and not
reusable!
Ok, does the [] do any conversion or any thing I don't want or
does it just make the template know we are working over an array?
Are there any performance issues? I am already using a for loop
to find the type, it's 6 lines of code. I was hoping to get that
down to one or 2 and make it a bit easier to understand.
App app = null;
for(int i = 0; i < Apps.length(); i++)
if ((Apps[i] !is null) && (Apps[i].hWnd == hWnd))
{
app = Apps[i];
break;
}
versus
find!("a.hWnd == b")(Apps[], hWnd);
Does [] take time to convert to a built in a array or range or
whatever or will it be just as fast as the above code?
Re: Improving CSV parsing performance, Episode 2 (Was: Re: Speed of csvReader)
On Sun, Jan 24, 2016 at 06:07:41AM +, Jesse Phillips via Digitalmars-d-learn wrote: [...] > My suggestion is to take the unittests used in std.csv and try to get > your code working with them. As fastcsv limitations would prevent > replacing the std.csv implementation the API may not need to match, > but keeping close to the same would be best. My thought is to integrate the fastcsv code into std.csv, such that the current std.csv code will serve as fallback in the cases where fastcsv's limitations would prevent it from being used, with fastcsv being chosen where possible. It may be possible to lift some of fastcsv's limitations, now that a few performance bottlenecks have been identified (validation, excessive number of small allocations, being the main ones). The code could be generalized a bit more while preserving the optimizations in these key areas. T -- BREAKFAST.COM halted...Cereal Port Not Responding. -- YHL
Re: nogc Array
On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
On Tuesday, 26 January 2016 at 03:06:40 UTC, maik klein wrote:
On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote:
Is there a GC-less array that we can use out of the box or do
I have to create my own?
https://dlang.org/phobos/std_container_array.html
How do we use std.algorithm with it? I could like to use find
but I have no luck.
I have
std.container.array!MyClass classes;
then std.algorithm.find!("a.myInt == b")(classes, 3)
I was hoping this would find the first object in classes who
has myInt == 3 but I just get many errors about not being able
to find the right definition.
I guess std.container.array isn't a range? Or am I using it
wrong?
First, should be std.container.array.Array!MyClass. However I
don't think(?) that the Array struct is a range itself, you might
have to use classes[] instead to get a slice of the array.
Re: nogc Array
On Tuesday, January 26, 2016 03:03:40 Igor via Digitalmars-d-learn wrote: > Is there a GC-less array that we can use out of the box or do I > have to create my own? If what you want is a dynamic array (as opposed std.container.Array), then you can simply malloc the memory and then slice it to get a dynamic array. It's just that it's then up to you to manage the memory properly, and if you attempt to append or concatenate, it'll result in the GC allocating a new array. - Jonathan M Davis
Re: nogc Array
On Tuesday, 26 January 2016 at 04:31:07 UTC, Igor wrote:
then std.algorithm.find!("a.myInt == b")(classes, 3)
Try
std.algorithm.find!("a.myInt == b")(classes[], 3)
notice the [] after classes
I guess std.container.array isn't a range? Or am I using it
wrong?
Containers aren't really ranges, they instead *offer* ranges that
iterate over them. Built in arrays are a bit special in that they
do this implicitly so the line is more blurred there, but it is a
general rule that you need to get a range out of a container.
Otherwise, consider that iterating over it with popFront would
result in the container being automatically emptied and not
reusable!
Re: how to allocate class without gc?
On Tuesday, 26 January 2016 at 05:11:54 UTC, Mike Parker wrote: On Tuesday, 26 January 2016 at 01:09:50 UTC, Igor wrote: Is there any examples that shows how to properly allocate an object of a class type with the new allocators and then release it when desired? Allocate a block of memory big enough to hold an instance of your class using whichever allocator you need, then instantiate a class instance with std.conv.emplace. http://p0nce.github.io/d-idioms/#Placement-new-with-emplace I created a class using this example. But my code is now failing. It seems one can't just replace new with this and expect it to work? What is happening is some fields(strings) are not retaining their value. ubyte[__traits(classInstanceSize, App)] buffer; auto app = cast(App)emplace!App(buffer[]); //auto app = new App(); Basically the comment is the original. When I finally call createWindow, it fails because the string representing the name inside App is null... Which doesn't happen when I use new. Should it work as expected(which it isn't) or do I have to also emplace all the fields and such so they are not for some reason released?
Re: New Win32 Core api broke?
On Monday, 25 January 2016 at 22:57:22 UTC, Igor wrote: error LNK2019: unresolved external symbol GetStockObject referenced in function _D2Application10createWindowMFPFZvZi (int Application.createWindow(void function()*)) and the line of code is wc.hbrBackground = GetStockObject(WHITE_BRUSH); I've tried to import core.sys.windows.wingdi; But that just got me to this error. When I don't use it, the code compiles I was able to solve this problem by importing gdi32.lib on the command line. Shouldn't the module import the lib like it does for the other ones? or does it? For clarity, libraries are not imported, they are linked. *Modules* are imported. Imports are processed at compile time to determine which symbols are available for use in the current compilation units. Libraries and object files are processed by the linker after compilation and imports have no role to play in that. Unresolved external symbol errors are linker errors, meaning you used a symbol in your code, the linker looked for its copied form in all the available object files (including any libraries it was given) and couldn't find it. The Windows API is implemented in multiple libraries. I believe DMD links to kernel32.lib and user32.lib by default, as those contain the most commonly used functions, but if you want to call any functions from any of the other Win32 libraries, you will need to link with them manually either by passing them on the command line or by using a lib pragma. If you aren't sure which library needs linking with when you get a missing symbol, the thing to do is to look up the function in the MSDN (Microsoft Developer Network) documentation and it will tell you which library you need. Usually it's enough to feed the function to Google and you will get the MSDN page in one of the first few links (though you'll need to make sure to go to the Win32 API page and not the documentation for the .NET version of the function).
Re: New Win32 Core api broke?
On Tuesday, 26 January 2016 at 05:05:43 UTC, Mike Parker wrote: the linker looked for its copied form *compiled* form
Re: is there a set container?
The std.container.RedBlackTree is close: http://dlang.org/phobos/std_container_rbtree.html Or you may prefer my work-in-progress unofficial docs: http://dpldocs.info/experimental-docs/std.container.rbtree.RedBlackTree.html You can see methods there like insert, removeKey, and opBinaryRight, which is actually the in operator: http://dpldocs.info/experimental-docs/std.container.rbtree.RedBlackTree.opBinaryRight.html to see if an element exists in the set. Create a red black tree with this convenience function: http://dpldocs.info/experimental-docs/std.container.rbtree.redBlackTree.1.html
is there a set container?
Hello, I am looking for data structure equivalent to std::set from C++. Couldn't find it in the documentation.
Error using templates: "cannot use template to add field to aggregate ''"
I'm getting several of these since I'm trying to do the same
thing in a few places. Here's a complete error:
path\to\file.d(55): Error: variable
units.unitvalue.opmethod!("sum(in unitvalue value)",
"add(value)").methodtemplate cannot use template to add field to
aggregate 'unitvalue'
path\to\file.d(127): Error: template instance
units.unitvalue.opmethod!("sum(in unitvalue value)",
"add(value)") error instantiating
In this class I wrote a number of methods like "multiply",
"divide", "add", "subtract" and I want to add alternatives that
don't modify the object. In this particular instance, I'm trying
to wrap the "add" method in another named "sum" that doesn't
modify the original object, simply by making a copy first and
operating upon that instead.
What am I doing wrong?
The relevant bits of my class look like this:
class unitvalue{
double coefficient;
int[unit] exponents;
unitvalue copy(){
unitvalue value = new unitvalue();
value.coefficient = this.coefficient;
value.exponents = this.exponents.dup;
return value;
}
template opmethod(string methoddef, string methodcall){
const char[] methodtemplate =
"unitvalue " ~ methoddef ~ "{
unitvalue copy = this.copy();
copy." ~ methodcall ~ ";
return copy;
}"
;
}
mixin(unitvalue.opmethod!(
"sum(in unitvalue value)", "add(value)"
));
void add(in unitvalue value){
if(!this.samedimensions(value)){
throw new Exception("Cannot add values of differing
dimensions.");
}else{
this.coefficient += value.coefficient;
}
}
bool samedimensions(in unitvalue value){
return this.exponents == value.exponents;
}
}
Re: Collapsing n-dimensional array to linear (1 dimensional)
On Monday, 25 January 2016 at 08:31:14 UTC, abad wrote: On Monday, 25 January 2016 at 02:27:57 UTC, Solomon E wrote: On Saturday, 23 January 2016 at 07:57:55 UTC, Ali Çehreli Ruby's Array class includes this sort method for flattening and for me it was surprisingly useful, for instance when it was necessary to write the array to file. D could certainly add a few more helper functions to work on multidimensional data or perhaps an article, I admit I was unaware joiner could be chained without mapping like that. One that regularly irritates me is arrays of results that you want to make eager such that you can map a lazy function to a 2D array and then store the result in a 2D array again. This seems messy and I'd like a function that will take absolutely anything and force eager assessment. auto a = res.map!array.array; // De-lazying 2D result Would like: auto a = res.eager;
D Dll's usefulness
Can D Dll's be linked and used as if they were compiled directly
with the program? I was thinking of writing some library routines
and put them in a Dll but now I'm not thinking that would be very
useful because the Dll's won't export class like behavior.
in my DLL:
class MyClass { void foo() { } }
in my app:
auto c = new MyClass();
I'd like to use MyClass as if it were defined directly here, but
I think I can only load the dll and attach to foo? Is this right?
Since I'm the "owner" of the library I can always just "drag and
drop" the source code into the project to get the desired
behavior. I'd like the DLL to provide that to future projects
that may not have the source code. Either the DLL's don't support
this, which I think is the case, or I have to include a "header".
Hopefully there is a tool that could take a "library" that will
be used as a dll and strip it down into modules that can be
included into the main app so it can be used as if the source
code was directly compiled in.
Am I off target here?
Re: Error using templates: "cannot use template to add field to aggregate ''"
Thanks so much for the help! I'm still getting used to D's compile-time code.
Re: Error using templates: "cannot use template to add field to aggregate ''"
On 25.01.2016 15:51, pineapple wrote:
class unitvalue{
double coefficient;
int[unit] exponents;
unitvalue copy(){
unitvalue value = new unitvalue();
value.coefficient = this.coefficient;
value.exponents = this.exponents.dup;
return value;
}
template opmethod(string methoddef, string methodcall){
const char[] methodtemplate =
Can't have variables like that in templates. Make it a "manifest
constant" with enum. Also, if you want opmethod!("foo", "bar") to
evaluate to the code, then methodtemplate needs to be renamed to
"opmethod". I.e., make this line:
enum opmethod =
Also, opmethod doesn't need to be template. A function would work as well:
static string opmethod(string methoddef, string methodcall)
{
return
"unitvalue " ~ methoddef ~ "{
unitvalue copy = this.copy();
copy." ~ methodcall ~ ";
return copy;
}"
;
}
mixin(unitvalue.opmethod(
"sum(in unitvalue value)", "add(value)"
));
"unitvalue " ~ methoddef ~ "{
unitvalue copy = this.copy();
copy." ~ methodcall ~ ";
return copy;
}"
;
}
mixin(unitvalue.opmethod!(
"sum(in unitvalue value)", "add(value)"
));
void add(in unitvalue value){
if(!this.samedimensions(value)){
throw new Exception("Cannot add values of differing
dimensions.");
}else{
this.coefficient += value.coefficient;
}
}
bool samedimensions(in unitvalue value){
return this.exponents == value.exponents;
This gives me an error, too: "Error: incompatible types for
((this.exponents) == (value.exponents)): 'int[int]' and 'const(int[int])'"
(I've aliased unit to int.)
As far as I can tell, this should work. There's a bugzilla issue for it:
https://issues.dlang.org/show_bug.cgi?id=13622
You can work around the bogus error message by using a const temporary
for this.exponent:
const this_exponents = this.exponents;
return this_exponents == value.exponents;
}
}
Re: Error using templates: "cannot use template to add field to aggregate ''"
On Mon, 25 Jan 2016 14:51:21 +, pineapple wrote:
> I'm getting several of these since I'm trying to do the same thing in a
> few places. Here's a complete error:
>
> path\to\file.d(55): Error: variable
> units.unitvalue.opmethod!("sum(in unitvalue value)",
> "add(value)").methodtemplate cannot use template to add field to
> aggregate 'unitvalue'
> path\to\file.d(127): Error: template instance
> units.unitvalue.opmethod!("sum(in unitvalue value)", "add(value)") error
> instantiating
That looks like the right error.
> template opmethod(string methoddef, string methodcall){
> const char[] methodtemplate =
Change it from 'const' to 'enum' and Bob's your uncle.
Short explanation:
'enum' refers to compile-time constants. 'const' is a promise that you
will not mutate a variable through that reference. Anything that's not a
compile-time constant in an aggregate body requires storage space within
that aggregate, resulting in an unbounded set of fields.
Exhaustive explanation:
'const' indicates that you cannot mutate the data through this reference
(but it can be mutated elsewhere). It's not referring to compile-time
constants. For instance, it's entirely legal (and reasonable) to write:
class OptParse {
const(string[]) args;
this(const(string[]) args) {
this.args = args;
}
}
void main(string[] args) {
new OptParse(args);
}
Which indicates that OptParse is not going to modify the args array.
You're grabbing command-line arguments and passing them in, which means
they're not a compile-time constant. So the OptParse class has to include
a storage slot reserved for the 'args' variable.
In your case, 'methodtemplate' isn't declared as a compile-time constant.
It has an initializer that's a compile-time constant, but you aren't
guaranteeing that the value isn't going to be changed.
That would be fine, but it's inside a template. Templates can be
instantiated a potentially unlimited number of times. So the compiler
comes across this type, tries to compute its size and fields -- but it
doesn't know for certain at this point how many times you're
instantiating the template. So it can't list out all the fields.
It would be possible if D compiled a whole program at once. This would
prevent you from publishing closed-source libraries, however, and
increase compilation times.
Re: First project: questions on how-to, and on language features
On 01/24/2016 04:26 AM, Marc Schütz wrote: >> (2) In the unittest code, I have a block that I want to rewrite using >> assertThrown, but I can't figure out from either the book or the >> website the correct usage. What's the right way to specify a >> StringException with a particular message I expect to receive? > > Here's the relevant documentation: > https://dlang.org/phobos/std_exception.html#.assertThrown > https://dlang.org/phobos/std_exception.html#.collectExceptionMsg Here is another link for completeness: http://ddili.org/ders/d.en/unit_testing.html#ix_unit_testing.assertThrown,%20std.exception Ali
Re: D Dll's usefulness
Um... A closed-source library is one thing, DLL is another thing, DLL class library is a third thing, seamless linking of DLL class library is a fourth thing. Well... see what you can get working.
Re: D Dll's usefulness
On Monday, 25 January 2016 at 21:42:07 UTC, Kagamin wrote: Um... A closed-source library is one thing, DLL is another thing, DLL class library is a third thing, seamless linking of DLL class library is a fourth thing. Well... see what you can get working. Thanks for the help! I really appreciate your wisdom and hospitality! Give me your address and I'll send you a thank you card!
New Win32 Core api broke?
error LNK2019: unresolved external symbol GetStockObject referenced in function _D2Application10createWindowMFPFZvZi (int Application.createWindow(void function()*)) and the line of code is wc.hbrBackground = GetStockObject(WHITE_BRUSH); I've tried to import core.sys.windows.wingdi; But that just got me to this error. When I don't use it, the code compiles I was able to solve this problem by importing gdi32.lib on the command line. Shouldn't the module import the lib like it does for the other ones? or does it?
static assignment
how can I have a static assignment
static bool isStarted = false;
public static Application Start(string Name, void
function(Application) entryPoint)
{
if (isStarted)
assert("Can only call Start once");
isStarted = true;
...
but I don't want this a runtime check. I want to know at compile
time. Start should never be used more than once in the entire
program. It's only used to get control from windows startup. It's
only called in the static this() of the main module.
changing stuff to static if and static assert doesn't help. I
tried enum, const, etc but all prevent setting isStarted to true.
Re: static assignment
On 1/25/16 8:40 PM, Igor wrote:
how can I have a static assignment
static bool isStarted = false;
public static Application Start(string Name, void
function(Application) entryPoint)
{
if (isStarted)
assert("Can only call Start once");
isStarted = true;
...
but I don't want this a runtime check.
I'm not sure you even need to worry about this check at all. Just don't
call the function again!
If you don't want other modules to have access, make the function
private in its own module. Then nothing else can call it. Of course, you
have to either name it properly or have the startup code in the same
module (I'm unsure how Windows does this).
But I think if you want the check, it necessarily must be during
runtime. At compile time, the code isn't running, it's just compiling.
-Steve
how to allocate class without gc?
Is there any examples that shows how to properly allocate an object of a class type with the new allocators and then release it when desired?
Re: Collapsing n-dimensional array to linear (1 dimensional)
On Monday, 25 January 2016 at 02:27:57 UTC, Solomon E wrote:
On Saturday, 23 January 2016 at 07:57:55 UTC, Ali Çehreli wrote:
auto collapse(R)(R r)
if (isArray!R) {
return r.joiner.collapse.joiner;
}
auto collapse(R)(R r)
if (!isArray!R) {
return r;
}
Ali, that code only passed the one test it had for collapsing a
three level array. It wouldn't collapse arrays of other numbers
of levels. It wasn't recursing as appeared to be intended.
Is the following code better D? (I don't know because I'm still
learning D, so I'd like to be corrected if the comments in my
code are inaccurate or misleading.)
(See https://issues.dlang.org/show_bug.cgi?id=12062 for where I
got the idea that `flatten` should be defined to mutate by
reference. A comment there suggests to use
std.experimental.ndslice and byElement for that, but ndlslice
doesn't seem to be in the library anymore.)
I will give this a try later.
Ruby's Array class includes this sort method for flattening and
for me it was surprisingly useful, for instance when it was
necessary to write the array to file.
I will also take a look at ndslice and see how intuitive its
approach for achieving this would be.
How can i track the GC when it's runing?
I want to know How can i track the GC when it's runing? And Which algorithm is D's GC used,only Scan-Mark?
Re: How can i track the GC when it's runing?
On Monday, 25 January 2016 at 09:33:15 UTC, Dsby wrote: I want to know How can i track the GC when it's runing? And Which algorithm is D's GC used,only Scan-Mark? There is a good resource here: https://dlang.org/spec/garbage.html It details compiler flags to use to profile and log the GC usage.
nogc Array
Is there a GC-less array that we can use out of the box or do I have to create my own?
Re: nogc Array
On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote: Is there a GC-less array that we can use out of the box or do I have to create my own? https://dlang.org/phobos/std_container_array.html
Re: nogc Array
On Tuesday, 26 January 2016 at 03:03:40 UTC, Igor wrote: Is there a GC-less array that we can use out of the box or do I have to create my own? There's one in emsi containers.
