Re: Window created with Windows API is not visible
On Saturday, 18 June 2022 at 23:00:36 UTC, solidstate1991 wrote: This is going to be a long match. you might consider using another exisitng lib. my simpledisplay.d does all this and much more for example
Re: Comparing Exceptions and Errors
On Saturday, 4 June 2022 at 22:31:38 UTC, Ola Fosheim Grøstad wrote: So what do you have to do to avoid having Errors thrown? How do you make your task/handler fault tolerant in 100% @safe code? Run it in a separate process with minimum shared memory.
Re: What happened to Deimos and why ?
On Saturday, 4 June 2022 at 13:44:06 UTC, Alain De Vos wrote: What happened to Deimos and why ? Nothing, it does its job same as it always has.
Re: How to fix "typesafe variadic function parameter"?
On Tuesday, 24 May 2022 at 22:46:55 UTC, Andrey Zherikov wrote: return S(s); return S(s.dup); The variadic lives in a temporary array that expires at the end of the function. So copying it out to the GC lets it live on. Your code was wrong on 2.099 too, but the compiler didn't tell you.
Re: Cannot check function address
On Tuesday, 24 May 2022 at 18:54:33 UTC, frame wrote: Usually that works fine as shown in module A but for some reason not in module B. Do you have some other definition of fun somewhere?
Re: How to call destroy() in @nogc?
On Tuesday, 24 May 2022 at 14:11:57 UTC, Steven Schveighoffer wrote: Note it has no idea what the real object type is at this point, just that it is an Object (which does not have a @nogc destructor). It actually has nothing to do with Object. It doesn't have a destructor at all, so there's no problem calling it from any context. The real problem is that destructors don't actually use the virtual machinery and call super(), meaning it is impossible to tell at compile time what they're doing at all. I know I wrote at length about this somewhere but can't find it right now. Probably in the chatroom. But even if you know static type, you can't make assumptions about the dynamic type since destructors (for no good reason tbh) don't follow the same rules as other virtual methods, despite the spec saying they are virtual.
Re: Error: undefined symbol: _WinMain@16 When try compile no console
On Thursday, 19 May 2022 at 21:41:50 UTC, Marcone wrote: Are you using the `-L/entry:mainCRTStartup` or the `L/entry:wmainCRTStartup` ? -L/entry:mainCRTStartup try the w one too. both doing the same result?
Re: Library for image editing and text insertion
On Tuesday, 26 April 2022 at 18:31:49 UTC, H. S. Teoh wrote:
maybe look at Adam Ruppe's arsd library
(https://github.com/adamdruppe/arsd) for some lightweight
modules that read common image formats and do some primitive
image manipulations.
I don't actually have an image to image blit function, but
writing one is trivial - just loop over it and call alphaBlend.
It can load ttf fonts, render them to bitmaps, load images,
combined them, then save images. Can even load ttfs off the
operating system if you wanted to use those or even have the
OS functions do the drawing instead of diy, but probably easier
to diy this simple case.
Sample code would be:
---
import arsd.image;
import arsd.ttf;
void main() {
auto image = loadImageFromFile("/home/me/small-clouds.png");
if(image is null)
throw new Exception("Couldn't load the image file");
auto tci = image.getAsTrueColorImage(); // convert to rgba for
simplicity
import std.file;
auto font = TtfFont(cast(ubyte[])
std.file.read("/home/me/arsd/sans-serif.ttf"));
int width, height;
auto bitmap = font.renderString("Hello", 14, width, height); //
it populates width and height fyi
// where we want to put it
int xput = 30;
int yput = 20;
int bitmapOffset = 0;
// color to draw the text
int r = 255;
int g = 0;
int b = 0;
foreach(y; 0 .. height) {
if(y + yput >= image.height)
break;
foreach(x; 0 .. width) {
scope(exit) bitmapOffset++; // always advance this as long as
we're still drawing...
// but don't draw out of bounds
if(x + xput >= image.width)
continue;
// replace a pixel with the blended version of the text
bitmap
image.setPixel(
xput + x, yput + y,
image.getPixel(xput + x, yput + y).
alphaBlend(Color(r, g, b,
bitmap[bitmapOffset]))
);
}
}
import arsd.png;
writePng("text-image.png", image); // save it back to a png
}
---
Open the text-image.png to see the result. (Or:
---
import arsd.simpledisplay;
displayImage(Image.fromMemoryImage(image));
---
to display it in a window right from your program!)
My libs are available as individual files from the github - you
might just use png instead of the whole image.d to avoid needing
additional files for formats you don't need - or you can pull it
on dub under the arsd-official:image_files package and
arsd-official:ttf.
Re: A template construct like using()
On Tuesday, 26 April 2022 at 23:00:57 UTC, cc wrote: If your draw code doesn't depend on any scoped state you can use `function()` instead of `delegate()` to save a GC call. `scope delegate` also works here and just reuses the stack.
Re: Beginner memory question.
On Saturday, 16 April 2022 at 20:41:25 UTC, WhatMeWorry wrote: Is virtual memory entering into the equation? Probably. Memory allocated doesn't physically exist until written to a lot of the time.
Re: TIC-80 WebAssembly: pointers to fixed addresses
On Saturday, 16 April 2022 at 14:29:09 UTC, Pierce Ng wrote:
```
pub const FRAMEBUFFER: *allowzero volatile [16320]u8 =
@intToPtr(*allowzero volatile [16320]u8, 0);
pub const TILES : *[8192]u8 = @intToPtr(*[8192]u8, 0x4000);
pub const SPRITES : *[8192]u8 = @intToPtr(*[8192]u8, 0x6000);
```
I believe the above is declaring that FRAMEBUFFER is a pointer
to 16320 (sic) bytes starting at address 0, TILES is a pointer
to 8192 bytes starting at address 0x4000, and SPRITES a pointer
to 8192 bytes starting at address 0x6000.
Currently for D I have the following, copying the D binding for
Wasm4, another fantasy console:
```
const FRAMEBUFFER = cast(uint*)0;
const TILES = cast(uint*)0x4000;
const SPRITES = cast(uint*)0x6000;
```
How to express in D, similarly to Zig, that FRAMEBUFFER refers
to a byte[16384] array starting from address zero, and so on?
Take the pointer and slice the pointer:
__gshared ubyte[] framebuffer = (cast(uint*) 0) [0 .. 16320]; //
gshared cuz otherwise D assumes it is TLS and it isn't
Now you can notice it isn't const. You don't want it const since
the point is to write to the thing. What you might do to keep the
pointer itself from ever changing is to make it a property:
ubyte[] framebuffer() { return (cast(uint*) 0) [0 .. 16320]; }
And the compiler will see how trivial that is and inline it so it
works the same way, but then nobody can ever rebind the
framebuffer symbol.
Re: arsd.minigui
On Sunday, 3 April 2022 at 16:58:03 UTC, JG wrote:
Hi,
I have an png image that I generate (via pdf via pdflatex) that
I want to scale and display in a widget. Is this possible via
something in arsd? I tried resizeImage but that doesn't seem to
do what I expect. Any suggestions?
Which resizeImage did you use, from the imageresize module? What
pain you have with it? Some of its settings take some tweaking.
Though in a widget, you can also stretch automatically on
Windows... actually XRender can do it too i believe but I never
implemented that. Maybe I should.
But imageresize should work with some experimentation. This is
how I did it in my image viewer application:
auto i = loadImageFromFile(arg);
auto size =
calculateSizeKeepingAspectRatio(i.width, i.height, maxWidth,
maxHeight);
if(size.width != i.width ||
size.height != i.height) {
i = imageResize(i,
size.width, size.height, null, 1.0, 0.6);
}
then pass that i to one of the minigui/simplediplay functions to
display.
Re: arsd-minigui - couple of questions
In fact, using a pragma now, I think I got it so you don't even need the manifest now (the pragma includes a default one now). Only works when doing dmd -m32mscoff or dmd -m64 builds (which are also what dub uses fyi), will NOT work with a default dmd no-switch build.
Re: arsd-minigui - couple of questions
oooh it actually is even easier than I thought, just a changed flag plus the manifest. Just pushed to minigui master. only ended up being 4 lines for this little thing. Try rebuilding with that AND be sure to use the manifest file too, same as dwt. Then you should be able to find some joy.
Re: arsd-minigui - couple of questions
On Monday, 28 March 2022 at 21:10:47 UTC, Sai wrote: FWIW, DWT which uses native controls on windows can show transparent pngs and also both image & text at the same time. However I had to add the following app.exe.manifest Yeah, this tells me they used owner-drawn buttons, which is only supported if you use version 6 controls. The version 6 controls are nice btw even if you don't use this specific feature, they also come with automatic theme support and a few other nice things. I actually recommend in the docs that you use this for simpledisplay/minigui applications too, just then you also need to provide a draw method to do the text+image. It isn't hard to do, about a dozen lines for this basic case that you can just opt into and use the default draw for other cases. I was thinking about adding one of those anyway (another nice thing you can do is change the background color), I just haven't gotten around to it yet. Maybe I'll do it tomorrow. Keep an eye on this thread, if I do, I'll let you know.
Re: arsd-minigui - couple of questions
On Monday, 28 March 2022 at 17:00:42 UTC, sai wrote: 1. I assume arsd-minigui library does not support transparent images by itself, does it? I am trying to show a png image with transparent areas on a button, but those transparent areas shows as black color. Well, I tried forwarding the flag, I can custom draw it this way but the standard Windows button's normal draw doesn't appear to care... There might be a trick I just don't know, but the problem is I don't know it lol.
Re: arsd-minigui - couple of questions
On Monday, 28 March 2022 at 17:00:42 UTC, sai wrote: 1. I assume arsd-minigui library does not support transparent images by itself, does it? I am trying to show a png image with transparent areas on a button, but those transparent areas shows as black color. I added that to simpledisplay last year, but never forwarded the flag to minigui since it didn't seem important should be easy enough to add, I'll take a look. 2. I want to show both image and text on a button, but looks like it shows image or text, but not both at the same time. Or am I missing some weird windows manifest stuff? Yeah, it is one or the other right now. I don't think the standard Windows control supports that without owner draw, which is something I've generally tried to avoid (but it isn't that hard to do at least in some cases...).
Re: Basic question about size_t and ulong
On Friday, 18 March 2022 at 21:54:55 UTC, WhatMeWorry wrote: Isn't ulong an integer? And isn't memory addresses 64 bits long? Only if you are doing a 64 bit build. Try using -m64
Re: static init c struct with array filed
On Thursday, 17 March 2022 at 00:16:39 UTC, Mike Parker wrote:
On Wednesday, 16 March 2022 at 07:27:06 UTC, test wrote:
```c
struct Test {
int32_t a;
}
struct Test2 {
int32_t a;
Test arr[];
}
```
I need static const init Test2, then pass it to c library
late(third library, can not change the type def).
Any time you see a '[]' in C, the equivalent declaration in D
has to be a pointer.
Not always with structs... if it has a fixed size or an
initializer in C, then you need to match the size in D.
Otherwise yeah use the pointer.
Re: forward tuple arg to local variable + dtor
You can't forward to a local variable. Local variables will be a copy of the tuple. forward only actually works if sent *directly* to another function call. There's a bunch of things in D that only work in function parameter lists and not local variables. This is one of them.
Re: Using getSymbolsByUDA in a static foreach loop
On Thursday, 20 January 2022 at 00:55:33 UTC, Jack Stouffer wrote: static foreach(member; __traits(allMembers, Manager)) member here is a string, not the member. I prefer to call it memberName. Then you __traits(getMember, Manager, memberName) to actually get the alias you can pass to getAttributes.
Re: Ambiguity issue with expanding and evaluating single template type parameter enums
On Tuesday, 28 December 2021 at 00:13:13 UTC, data pulverizer wrote: There are various requirements, sometimes I have to cast or type convert, so I **need** the type to paste correctly and explicitly. You almost never actually need types as strings. I'm almost certain there's a better way for you to get the same work done. Have you tried just using T directly in your mixin? You can frequently just use the local name and skip the string getting entirely.
Re: Ambiguity issue with expanding and evaluating single template type parameter enums
On Monday, 27 December 2021 at 21:21:30 UTC, data pulverizer
wrote:
alias T = MyType!(INTEGER);
What is MyType?
enum code = "writeln(\"instance: \", adder(" ~
T.stringof ~ "(), " ~ U.stringof ~ "()" ~ "));";
And why is this a string mixin instead of a plain simple function?
prolly need more context
Re: Ambiguity issue with expanding and evaluating single template type parameter enums
On Monday, 27 December 2021 at 21:05:51 UTC, data pulverizer wrote: adder(MyType!MyEnum.INTEGER(), MyType!MyEnum.STRING()); The rule for !(args) is of you leave the parenthesis off, it only uses the next single token as the argument. So it will never include a dot; it is like you wrote `MyType!(MyEnum).INTEGER`. You might just always use the () in your generated code when you create that mixin string can't just just change the generator to put the () around it? Or is the stringof generating this? (Another reason why stringof is terrible and should never be used ever for anything.) `MyType!MyEnum.STRING` is generated with `T.stringof `. I get the error: if you can paste teh code where you generate this I can prolly show you a much easier way to do it. stringof sucks really hard.
Re: How to print unicode characters (no library)?
On Sunday, 26 December 2021 at 20:50:39 UTC, rempas wrote: I want to do this without using any library by using the "write" system call directly with 64-bit Linux. write just transfers a sequence of bytes. It doesn't know nor care what they represent - that's for the receiving end to figure out. know (and tell me if I'm mistaken), UTF-16 and UTF-32 have fixed size lengths for their characters. You are mistaken. There's several exceptions, utf-16 can come in pairs, and even utf-32 has multiple "characters" that combine onto one thing on screen. I prefer to think of a string as a little virtual machine that can be run to produce output rather than actually being "characters". Even with plain ascii, consider the backspace "character" - it is more an instruction to go back than it is a thing that is displayed on its own. Now the UTF-8 string will report 11 characters and print them normally. This is because the *receiving program* treats them as utf-8 and runs it accordingly. Not all terminals will necessarily do this, and programs you pipe to can do it very differently. Now what about the other two? I was expecting UTF-16 to report 16 characters and UTF-32 to report 32 characters. The [w|d|]string.length function returns the number of elements in there, which is bytes for string, 16 bit elements for wstring (so bytes / 2), or 32 bit elements for dstring (so bytes / 4). This is not necessarily related to the number of characters displayed. Isn't the "write" system call just writing a sequence of characters without caring which they are? yes, it just passes bytes through. It doesn't know they are supposed to be characters...
Re: How to pass a class by (const) reference to C++
On Wednesday, 15 December 2021 at 22:24:42 UTC, H. S. Teoh wrote: `__gshared` is needed to coax the compiler into making the variable global in the C/C++ sense, i.e., only 1 instance across all threads. it is just normally __gshared implies static automatically. it does in like every other context but i guess not in the mangler or whatever.
Re: Why code failed to compile for foo2?
On Saturday, 11 December 2021 at 23:17:17 UTC, Stanislav Blinov wrote: ? No. If it was unsatisfied constraint, the error would've shown that. And if you try to instantiate it, you'll see it is an unsatisfied constraint anyway. There's two layers of failure here. Using Unqual there is pretty iffy, i wouldn't bother with it at all, but if you do anything, instead qualify it const. But either way, then the constraint still fails since int isn't unsigned. I'd really recommend simplifying this a lot.
Re: Why code failed to compile for foo2?
On Saturday, 11 December 2021 at 22:50:45 UTC, apz28 wrote:
void foo2(T)(Unqual!T x) if(isUnsigned!T) {}
This means it treats foo2 as if it doesn't exist unless T is
unsigned...
onlineapp.d(15): Error: template `onlineapp.foo2` cannot deduce
function from argument types `!()(int)`
onlineapp.d(7):Candidate is: `foo2(T)(Unqual!T x)`
*/
And this is telling you it had a signed value - int - which means
it doesn't match.
For the other ones, the functions still exist, so it does
whatever conversion it needs. Whereas with the template that
constraint means the compiler acts like it doesn't exist at all
and thus doesn't even attempt an automatic conversion.
Re: T... args!
On Wednesday, 8 December 2021 at 23:43:48 UTC, Salih Dincer wrote:
Is this not a contradiction? : and 3.1415 aren't string:
```d
void foo(string...)(string args) {
`string...` there is a user-defined identifier representing a mix
of types.
string isn't special, yo can declare your own variables with that
name. And that's what you did here.
I think you meant to say
void foo(string[] args...) {}
which is avariadtic number of only strings
Re: How to read a single character in D language?
On Friday, 19 November 2021 at 20:51:09 UTC, BoQsc wrote: But the source file overwhelmed me by its size. Yeah, the getch function in there builds on the rest of the events the library offers, so it won't be that useful outside. The OS functions for getch alone though are actually pretty simple: 1) change the terminal to "raw" mode. the default is to buffer lines, which means your application doesn't get anything until a line is complete. You need to turn that off. The RealTimeConsoleInput constructor does this in the lib: http://arsd-official.dpldocs.info/v10.3.8/source/arsd.terminal.d.html#L2487 On Windows, you basically just call `SetConsoleMode`, but since the console is a shared resource, you also need to save the old mode to set it back later (that's what I do in the destructor of the struct). On Linux, you call `tcsetattr`. The function for mine is here: http://arsd-official.dpldocs.info/v10.3.8/source/arsd.terminal.d.html#L2620 Again, the terminal is a shared resource (this is actually even more true on linux systems!) so it is important to save the old one and set it back when you're done. There's a lot of ways this can happen so you should handle them all - that's why there's a bunch of signal handler blocks there. Other things the library initialize is if you want echo, mouse input, paste events, resize notifications, etc. But if you only care about getch you can ignore most that stuff. 2) Read the terminal's event stream. On Windows, you call `ReadConsoleInput` and process the struct it sends you for a keyevent. See: http://arsd-official.dpldocs.info/v10.3.8/source/arsd.terminal.d.html#L3122 On Linux, you call the system `read` function on the stdin stream (file number 0). Basic keys will come as a single byte read on there. Others get extremely complicated. http://arsd-official.dpldocs.info/v10.3.8/source/arsd.terminal.d.html#L3369 And it goes on for about 400 lines! And it depends on some of that other initialization we skipped over before and uses a database of terminal quirks found elsewhere in the file. Windows' API is far, far easier to use. But the Linux one isn't bad if you only want basic alphanumeric and enter keys. You can read those as a single ascii byte off the read function, so for that you can do it in just a few lines. 3) Again, remember to set it back how you found it before you exit by callling the SetConsoleMode/tcsetattr again before you exit.
Re: arsd.simpledisplay on macos
On Tuesday, 16 November 2021 at 03:41:31 UTC, Ben Jones wrote: I'm trying to use Adam's simpledisplay on a mac with XQuartz which is installed + running. When I try to create a window, it crashes when calling `XDisplayConnection.get()`. Hmm, I have never actually seen that fail since the mac will start up the X server on demand. Nevertheless, you might want to try a few things: 1) run xquartz separately to ensure it is up 2) set hte DISPLAY=:0 environment variable before starting the sdpy app 3) also perhaps try DISPLAY=127.0.0.1:0 in case it isn't configured for it Also possible I bugged it since then though, since it dynamic loads the libs instead of static and I never actually tested that fully on mac. But I think if that was the case you'd get an abort instead of an exception; it wouldn't get to the connection failed step. r is there an example that seems to work with the native cocoa version? I'm only planning to use really basic functionality (display an image and maybe capture some key presses) I actually don't think the key press functions work anymore, but they are probably fairly easy to fix. You have to build it without dub so you can pass -version=OSXCocoa to the compiler. Then some things at least should work. But the Cocoa implementation was contributed to me back in like 2012 and I've spent very little time on it since then. At one point last year, I did get its window working again at least but not much else. It is liable to throw NotYetImplementedExceptions and might have regressed since then too. I have a mac vm i set up but it is a pain to use so I rarely bother Also, Adam, if you have an idea of what needs to be done to get native macos support working, I'm willing to try to give it a shot. So the existing code is an implementation of just the basic featureset built on extern(C) objc_msgSend calls. It is really ugly code and nothing I've added since 2012 works in there at all - anything more than the basic timer is not implemented, no file events, no opengl, no fonts. Even basic window methods probably won't work like maximize and show. What I'd really like to do is to use dmd's beautiful extern(Objective-C) interface to make the code easier to use. I was kinda hoping those would be added to druntime like core.sys.windows but apparently not. ldc hasn't even implemented the feature at all :( (ive been considering porting it from dmd to ldc myself for like 2 years but it is super low priority since in the rare times i use a mac, im ok with the X server) But yeah I don't know much about mac development and have a trillion other things to do.
Re: D modules
On Saturday, 13 November 2021 at 22:52:55 UTC, pascal111 wrote: When I'm searching for "toUpper" and "toLower" functions that string type uses They are usable though `import std.string;` the docs just don't do a great job showing that. The newest test version of my doc generator does integrate them into the member list though: http://dpldocs.info/experimental-docs/std.string.html My dpldocs.info website has a search engine too to help find the original place: dpldocs.info/toLower for example will point you at std.uni first. But if it is "public imported" into a member list of another module you can use it just importing either way.
Re: in a template, how can I get the parameter of a user defined attribute
On Saturday, 6 November 2021 at 19:45:49 UTC, Chris Bare wrote:
dbForeignKey!(Position)
static if(is(T == dbForeignKey!Arg, Arg)) {
// use Arg here
}
Re: How to do a function pointer to "malloc" and "free"?
On Sunday, 17 October 2021 at 23:07:15 UTC, Elmar wrote: Do you have a link for more information how to initialize the D runtime? Export a function that calls this: http://druntime.dpldocs.info/core.runtime.Runtime.initialize.html And also export a function that calls this: http://druntime.dpldocs.info/core.runtime.Runtime.terminate.html And tell the user to call those when they load/unload the library. (It is pretty common for C libraries to require explicit init/term calls so they should be used to it.) They refcount internally so it is ok to call multiple times, just make sure the init and term are always paired. (btw the druntime actually exports them as extern(C) rt_init/rt_term but I'd still recommend you do your own anyway. if you do have extra work to do you can just do it there, and it can use whatever your lib naming conventions are. and besides im not sure if the extern(C) things are specified stable (even though they have been for as long as i can remember), whereas doing your own thing that `import core.runtime; return Runtime.initalize;` is. )
Re: How to do a function pointer to "malloc" and "free"?
On Sunday, 10 October 2021 at 13:52:57 UTC, Elmar wrote: The language subset "BetterC" is required for calling D functions from C though. This is false. You can use any D features when calling it from C, you just need to provide an init and term function that is called from C that runtime initialize and terminate for the full experience. BetterC helper librarys like Tanya or Tango do exist. I don't know tanya, but Tango has absolutely nothing to do with betterC. It is a set of classes that use the full runtime.
Re: Better debugging?
On Sunday, 3 October 2021 at 22:21:45 UTC, Tim wrote: -gc DMD2 compiler switch tried plain -g ? -gc is a compatibility debug thing for things with zero D support. p oboslete now
Re: Template mixin problem with EnumMembers
On Saturday, 2 October 2021 at 22:07:23 UTC, Ferhat Kurtulmuş
wrote:
The below code works as expected on https://run.dlang.io/, but
not on my computer. And I don't know why?
You used .stringof. That's undefined behavior. Never use
stringof. (except for debugging writes)
Now, I'd actually probably do this entirely differently... just
using opDispatch.
```
class Options{
public:
enum StringOption {
OUT_FILE_NAME,
RPT_FILE_NAME,
MAP_FILE_NAME
}
static template opDispatch(string name)
if(__traits(hasMember, StringOption, name)) {
alias opDispatch = __traits(getMember, StringOption,
name);
}
}
```
and done. (even that `if` template constraint isn't really
necessary and im usally anti-those too, but here it kinda makes
sense. in theory. in practice it makes zero difference, but in
theory, if the dmd regression that broke these error messages
ever actually gets fixed, this would lead to better error
messages this way. but anyway moving on)
That opDispatch just creates the aliases on-demand. You can't
reflect over them directly if you wanted to - you'd still have to
check enum members of Options.StringOption, which means things
like std.conv.to won't pick it up, but it would work in normal
use quite beautifully.
If you did want to do the ahead-of-time static foreach way,
remember, never use .stringof. Find another way.
and tbh i'd ditch the std.traits thing too, it just complicates
things. Use the language feature allMembers directly and it
simplifies to this:
```
mixin template StrOptAliases()
{
static foreach(name; __traits(allMembers, StringOption))
mixin("alias " ~ name ~ " = " ~ " __traits(getMember,
StringOption, name);");
}
```
Notice that the ONLY thing outside the quotes to the mixin is the
name. Everything else is inside. That's often the solution to
follow my "never use stringof" advice - just leave things inside
the quotes. String interpolation / concat is actually very rarely
needed to build mixins. New declaration names are the main
exception. But most everything else can just be referenced
directly and it leads to code that is both less buggy and easier
to read.
And, of course, it doesn't rely on random underspecified
.stringof behavior that the compiler can change randomly in any
release which is just the cherry on top.
Re: Understanding range.dropBackOne
On Tuesday, 28 September 2021 at 22:56:17 UTC, Tim wrote: I'm doing the following: int[25] window = 0; Note that this array has a fixed size. window = someInteger ~ window[].dropBackOne; Here the window[] takes a variable-length slice of it. Turning it from int[25] into plain int[]. Then you can drop one since it is variable length. Then appending again ok cuz it is variable. Then the window assign just copies it out of the newly allocated variable back into the static length array. window = someInteger ~ window.dropBackOne; But over here you are trying to use the static array directly which again has fixed length, so it is impossible to cut an item off it or add another to it. What does the `[]` do exactly? Is an array not a bidirectional range? It takes a slice of the static array - fetching the pointer and length into runtime variables.
Re: Templates for instantiating derived class
On Monday, 20 September 2021 at 22:16:47 UTC, rjkilpatrick wrote:
auto opBinary(string op)(int rhs) const if (op == "+") {
return new Super(_a + rhs); // Creates of type Super
even when called from derived class
}
Make this
auto opBinary(string op, this This)(int rhs) .
return new This(_a + rhs);
}
The template this param is the static type it is called on.
https://dlang.org/spec/template.html#template_this_parameter
Note though that this is the static type. If you do
Super thing = new Derived();
thing + 5;
it will still return Super since that's the type it was called
through. If you want it to actually return derived, you'll have
to add a virtual factory function:
class Super {
protected Super factory() { return new Super(); }
}
class Derived : Super {
override Derived factory() { return new Derived(); }
}
Then you can call obj.factory to get the right dynamic type.
(forward args as needed etc.)
Some kind of `return new this(...)` would be good, but that's
not possible.
You can do `return new typeof(this)(...);` fyi but it is again
the static type of this, which will be whatever it is where it is
defined. This is a useful trick if you were to make that factory
function a mixin template or something though.
Re: interface function member declarations needing parameter attributes ?
On Saturday, 17 July 2021 at 20:42:06 UTC, someone wrote: From the interface perspective: are these signatures identical or not ? No, they are very different. But you also don't gain much from const here and that ref is probably actively harmful so i wouldn't use them here.
Re: function parameters: is it possible to pass byref ... while being optional at the same time ?
On Saturday, 17 July 2021 at 20:49:58 UTC, someone wrote: ref classTickerID robjTickerID Why are you using ref here at all? You probably shouldn't be using it. But if it is legitimately needed you can do a pointer instead of ref.
Re: UFCS doubt
On Thursday, 8 July 2021 at 22:24:26 UTC, Antonio wrote: I supossed that ```mfp(c,20)``` and ```c.mfp(20)``` should be equivalent because UFCS in second example, but it is not... why? UFCS only works with functions defined at top level, not nested inside other functions. That's just how it is defined i don't really know why.
