Re: why ushort alias casted to int?
On Friday, 22 December 2017 at 10:14:48 UTC, crimaniak wrote:
My code:
alias MemSize = ushort;
struct MemRegion
{
MemSize start;
MemSize length;
@property MemSize end() const { return start+length; }
}
Error: cannot implicitly convert expression
`cast(int)this.start + cast(int)this.length` of type `int` to
`ushort`
Both operands are the same type, so as I understand casting to
longest type is not needed at all, and longest type here is
ushort in any case. What am I doing wrong?
@property MemSize end() const { return cast(int)(start+length); }
The rule of int promotion of smaller types comes from C as they
said. There are 2 reason to do it that way. int is supposed in C
to be the natural arithmetic type of the CPU it runs on, i.e. the
default size the processor has the least difficulties to handle.
The second reason is that it allows to detect easily without much
hassle if the result of the operation is in range or not. When
doing arithmetic with small integer types, it is easy that the
result overflows. It is not that easy to define portably this
overflow behaviour. On some cpus it would require extra
instructions. D has inherited this behaviour so that copied
arithmetic code coming from C behaves in the same way.
@property MemSize end() const
{
MemSize result = start+length;
assert(result <= MemSize.max);
return cast(int)result;
}
with overflow arithmetic this code is not possible (as is if
MemSize was uint or ulong).
Re: std.file and non-English filename in Windows
On Sunday, 31 December 2017 at 18:21:29 UTC, Domain wrote: In Windows, exists, rename, copy will report file not exists when you input non-English filename, such as Chinese 中文.txt It's unclear what your problem is but here a wild guess. Windows API's for Unicode use UTF-16 as far as I know. Strings in D are utf-8. So before calling win32 API function, they have to be transformed to wstring i.e. utf-16 strings.
Re: Efficient way to pass struct as parameter
On Tuesday, 2 January 2018 at 23:27:22 UTC, H. S. Teoh wrote: When it comes to optimization, there are 3 rules: profile, profile, profile. I used to heavily hand-"optimize" my code a lot (I come from a strong C/C++ background -- premature optimization seems to be a common malady among us in that crowd). That's why I always tell that C++ is premature optimization oriented programming, aka as POOP.
Re: Bolts 0.4 meta programming library
On Thursday, 2 August 2018 at 08:45:33 UTC, John Colvin wrote: On Thursday, 2 August 2018 at 08:40:55 UTC, John Colvin wrote: [...] woops, pressed send too early: 2) I don't think "doth" is synonymous with "is" how you're using it. "doth" is for doing, e.g. "Methinks he doth protest too much" or "This code doth stink" is OK "Green doth a colour" or "strstr doth a function" is not OK. Isn't "doth" just an antiquated orthography of "does"?
Re: Bolts 0.4 meta programming library
On Thursday, 2 August 2018 at 10:31:02 UTC, aliak wrote: On Thursday, 2 August 2018 at 08:45:33 UTC, John Colvin wrote: [...] Thanks! And yes, totally aware of that. I have tried to link to relevant forum posts and will try to add more as I go along to where the usages were concocted. So I guess those could be the motivations? But it'd also be nice to just use it for a while and get feedback and experience with the names/APIs/functionalities/etc before adding it to std.meta. Though being in std would be ideal of course. [...] Dammit! You're right! Thank you for pointing that out. Art! It's Art! ... or maybe i can use a hipster "is" ... i.e. "iz" :p ’tis like in "’Tis the season to be jolly." https://en.wiktionary.org/wiki/'tis Ok, Unicode (’ U+2019) in a symbol is not nice but works normally in D. :-)
Re: DWT API Documentation now on dpldocs.info
On Thursday, 8 March 2018 at 01:21:44 UTC, Adam D. Ruppe wrote: As some of you might know, DWT is a D port of Java's SWT. It is as thus nearly identical and you can use Java's documentation with very little effort - copy/paste of Java examples almost just work as D too. [...] Thank you, Adam. You made my day!
Re: std.variant Is Everything Cool About D
On Friday, 30 March 2018 at 03:54:21 UTC, Mike Parker wrote: On Friday, 30 March 2018 at 02:46:13 UTC, jmh530 wrote: On Friday, 30 March 2018 at 00:37:27 UTC, Meta wrote: Unfortunately, this turned out to be the worst possible day for me to try to actively monitor the thread and respond to questions. I'm surprised that people latched onto my little quip about C++ using the name variant for a tagged union. It seems that any comment in a D article that refers to C++ will be construed in the worst possible way on reddit... That's fine by me. Right now, this post is the fourth most-viewed this year and it's not far off from number three. While I would love to please the reddit crowd to the extent that we see no negativity, I'm quite happy with the fact that our comment threads there are nowhere near as negative as they used to be. Posts that do generate this level of discussion have higher views. I can't dismiss reddit comments completely, but I don't put as much weight on them as I used to. A subreddit is somewhat comparable to a forum for a popular video game -- lots of vocal people who are actually a small minority of the player base. We can't measure the number of people who click the reddit link to the blog and come away from it with a positive impression. They aren't going to bother commenting on reddit. You're right and the unreasonable position of the SolidStateGraphics user is clear for everyone to see. There are some points he makes that could be discussed but by holding essentially the position "D is shit because it is not C++" his whole argumentation falls apart as Stockholm-syndrome induced rationalisation.
Re: Compile time initialization of AA
On Friday, 23 March 2018 at 22:43:47 UTC, Xavier Bigand wrote:
I am trying to initialize an global immutable associative array
of structs, but it doesn't compile.
I am getting the following error message : "Error: not an
associative array initializer".
As I really need to store my data for a compile time purpose if
we can't do that with AA, I'll use arrays instead.
Here is my code :
struct EntryPoint
{
string moduleName;
string functionName;
boolbeforeForwarding = false;
}
immutable EntryPoint[string] entryPoints = [
"wglDescribePixelFormat":
{moduleName:"opengl32.forward_initialization",
functionName:"wglDescribePixelFormat"}
];
Another solution, radically different is to not use an AA but a
simple array.
Instead of indexing on a string you could simply index on an enum
type. As your array is compile time constant, the dynamic nature
of AA is not really used and indexing on a enum value is faster
and simpler anyway.
The trick here is to generate the enum type at compile time. This
can be achieved by a string mixin built at compile time.
Here an example that I used to generate an enum from the values
from another enum. In your case you can look where the
"wglDescribePixelFormat" are defined and using imports or string
building code.
mixin({
string code = "enum LANBIT : ulong { "~
"init = 0,"; /* We set the dummy
init value to 0 */
foreach(lanCode; __traits(allMembers, LANIDX)) {
static if(lanCode == "IN")
code ~= "INVALID = LANIDX2LANID(LANIDX."~lanCode~"),";
else
code ~= lanCode~"= LANIDX2LANID(LANIDX."~lanCode~"),";
}
code ~= "
ALL= INVALID-1, /**< All bits except
the LANID_INVALID */
OFFICIAL=
BG|CS|DA|DE|EL|EN|ES|ET|FI|FR|GA|HR|HU|IT|LT|LV|MT|NL|PL|PT|RO|SK|SL|SV, /**< Official languages of the EU */
COOFFICIAL=CA|GL|EU|GD|CY /**< Co-official
languages of the EU */
";
return code ~ "}";
}());
TL/DR
defining constant compile time AA is an oxymoron. AA are by
nature dynamic runtime creatures. if the indexes are compile
time, a normal array with fixed indexes is enough.
Re: Beta 2.079.0
On Monday, 19 February 2018 at 10:49:03 UTC, Martin Nowak wrote: Glad to announce the first beta for the 2.079.0 release, ♥ to the 77 contributors for this release. [...] On Monday, 19 February 2018 at 10:49:03 UTC, Martin Nowak wrote: Just for information. DWT doesn't build with 2.079 because of overloads not allowed . I'm not good enough to do something about it but only wanted to make people aware of it. I also opened an issue at the dwt project.
Re: Why is stdio ... stdio?
On Saturday, 10 November 2018 at 18:47:19 UTC, Chris Katko wrote: On Saturday, 10 November 2018 at 13:53:14 UTC, Kagamin wrote: [...] There is another possibility. Have the website run (fallible) heuristics to detect a snippet of code and automatically generate it. That would leave the mailing list people completely unchanged. [...] Simply using markup convention used in stackoverflow and reddit of formatting as code when indented by 4 blanks would already be a good step forward. I do it now even on newsgroup like comp.lang.c, the only newsgroup I still use via thunderbird (yeah, for the D groups I prefer the web interface which is really that good, contrary to all other web based newsgroup reader I ever saw). [...]
Re: Profiling DMD's Compilation Time with dmdprof
On Tuesday, 6 November 2018 at 21:52:30 UTC, H. S. Teoh wrote: On Tue, Nov 06, 2018 at 07:44:41PM +, Atila Neves via Digitalmars-d-announce wrote: On Tuesday, 6 November 2018 at 18:00:22 UTC, Vladimir Panteleev wrote: > This is a tool + article I wrote in February, but never got > around to finishing / publishing until today. > > https://blog.thecybershadow.net/2018/02/07/dmdprof/ > > Hopefully someone will find it useful. Awesome, great work! I really really hate waiting for the compiler. OTOH, I really really hate that the compiler, in the name of faster compilation, eats up all available RAM and gets OOM-killed on a low memory system, so no amount of waiting will get me an executable. Now that the compiler is completely in D, wouldn't it be a good idea to activate the GC in the compiler. I know that it requires some care for bootstrapping the compiler when there are dependencies to the D runtime, but the compiler would be an excellent example of the advantage of the GC (i.e. dumb fast allocations as long as there's memory, collection when no memory left which is miles away better than to get OOM-killed).
Re: Converting a character to upper case in string
On Saturday, 22 September 2018 at 06:01:20 UTC, Vladimir Panteleev wrote: On Friday, 21 September 2018 at 12:15:52 UTC, NX wrote: How can I properly convert a character, say, first one to upper case in a unicode correct manner? That would depend on how you'd define correctness. If your application needs to support "all" languages, then (depending how you interpret it) the task may not be meaningful, as some languages don't have the notion of "upper-case" or even "character" (as an individual glyph). Some languages do have those notions, but they serve a specific purpose that doesn't align with the one in English (e.g. Lojban). There are other traps in the question of uppercase/lowercase which makes is indeed very difficult to handle correctly if we don't define what correctly means. Examples: - It may be necessary to know the locale, i.e. the language of the string to uppercase. In Turkish uppercase of i is not I but İ and lowercase of I is ı (that was a reason for the calamitous low performance of toUpper/toLower in Java for example. - Some uppercases depend on what they are used for. German ß shouldbe uppercased as SS (note also btw that 1 codepoint becomes 2 in uppercase) in normal text, but for calligraphic work, road signs and other usages it can be capital ẞ. - Greek has 2 lowercase forms for Σ but two lowercase forms σ and ς depending on the word position. - While it becomes less and less relevant Serbo-croatian may use digraphs when transcoding the script from Cyrillic (Serbian) to Latin (Croatian), these digraphs have 2 uppercase forms (title-case and all capital): - dž -> DŽ or Dž - lj -> LJ or Lj - NJ -> Nj or nj Normalization would normally take care of that case. - Some languages may modify or remove diacritical signs when uppercasing. It is quite usual in French to not put accents on capitals. It is also clear that the operation of uppercasing is not symetric with lowercasing. In which code level I should be working on? Grapheme? Or maybe code point is sufficient? Using graphemes is necessary if you need to support e.g. combining marks (e.g. ̏◌ + S = ̏S).
Re: Compiling to 68K processor (Maybe GDC?)
On Sunday, 20 January 2019 at 09:27:33 UTC, Jonathan M Davis wrote: On Saturday, January 19, 2019 10:45:41 AM MST Patrick Schluter via Digitalmars-d-learn wrote: On Saturday, 19 January 2019 at 12:54:28 UTC, rikki cattermole wrote: > [...] At least 68030 (or 68020+68851) would be necessary for proper segfault managing (MMU) and an OS that uses it. Afaict NULL pointer derefernecing must fault for D to be "usable". At least all code is written with that assumption. For @safe to work properly, dereferencing null must be @safe, which means more or less means that either it results in a segfault, or the compiler has to add additional checks to ensure that null isn't dereferenced. The situation does get a bit more complicated in the details (e.g. calling a non-virtual member function on a null pointer or reference wouldn't segfault if the object's members are never actually accessed, and that's fine, because it doesn't violate @safe), but in general, either a segfault must occur, or the compiler has to add extra checks so that invalid memory is not accessed. At this point, AFAIK, all of the D compilers assume that dereferencing null will segfault, and they don't ever add additional checks. If an architecture does not segfault when dereferencing null, then it will need special handling by the compiler, and I don't think that ever happens right now. So, if D were compiled on such an architecture, @safe wouldn't provide the full guarantees that it's supposed to. Ok, thanks for the explanation. This said, my statement that a PMMU is required for NULL pointer segfaults is wrong. Even 68000 can segfault on NULL dereference in user mode at least (the famous bus error 2 bombs on Atari ST or guru meditations on Amiga). In priviledged mode though it's not the case as there is memory at address 0 (reset vector) that might be necessary to access by an OS.
Re: Compiling to 68K processor (Maybe GDC?)
On Saturday, 19 January 2019 at 12:54:28 UTC, rikki cattermole wrote: On 20/01/2019 1:38 AM, Edgar Vivar wrote: Hi, I have a project aiming to old 68K processor. While I don't think DMD would be able for this on the other hand I think GDC can, am I right? If yes would be any restriction of features to be used? Or the compiler would be smart enough to handle this properly? Edgar V. Potentially. D is designed to only work on 32bit+ architectures. The 68k series did have 32bit versions of them. After a quick check it does look like LDC is out as LLVM has not yet got support for M68k target. Which is unfortunate because with the -betterC flag it could have pretty much out of the box worked. Even if you don't have most of D at your disposal e.g. classes and GC (but hey old cpu! can't expect that). I have no idea about GDC, but the -betterC flag is pretty recent so its support may not be what you would consider first class there yet. At least 68030 (or 68020+68851) would be necessary for proper segfault managing (MMU) and an OS that uses it. Afaict NULL pointer derefernecing must fault for D to be "usable". At least all code is written with that assumption.
Re: Why does nobody seem to think that `null` is a serious problem in D?
On Tuesday, 20 November 2018 at 23:14:27 UTC, Johan Engelen wrote:
On Tuesday, 20 November 2018 at 19:11:46 UTC, Steven
Schveighoffer wrote:
On 11/20/18 1:04 PM, Johan Engelen wrote:
D does not make dereferencing on class objects explicit,
which makes it harder to see where the dereference is
happening.
Again, the terms are confusing. You just said the dereference
happens at a.foo(), right? I would consider the dereference to
happen when the object's data is used. i.e. when you read or
write what the pointer points at.
But `a.foo()` is already using the object's data: it is
accessing a function of the object and calling it. Whether it
is a virtual function, or a final function, that shouldn't
matter.
It matters a lot. A virtual function is a pointer that is in the
instance, so there is a derefernce of the this pointer to get the
address of the function.
For a final function, the address of the function is known at
compile time and no dereferencing is necessary.
That is a thing that a lot of people do not get, a member
function and a plain function are basically the same thing. What
distinguishes them, is their mangled name. You can call a non
virtual member function from an assembly source if you know the
symbol name.
UFCS uses this fact, that member function and plain function are
indistinguishable in a object code point of view, to fake member
functions.
There are different ways of implementing class function calls,
but here often people seem to pin things down to one specific
way. I feel I stand alone in the D community in treating the
language in this abstract sense (like C and C++ do, other
languages I don't know). It's similar to that people think that
local variables and the function return address are put on a
stack; even though that is just an implementation detail that
is free to be changed (and does often change: local variables
are regularly _not_ stored on the stack [*]).
Optimization isn't allowed to change behavior of a program, yet
already simple dead-code-elimination would when null
dereference is not treated as UB or when it is not guarded by a
null check. Here is an example of code that also does what you
call a "dereference" (read object data member):
```
class A {
int i;
final void foo() {
int a = i; // no crash with -O
}
}
void main() {
A a;
a.foo(); // dereference happens
}
No. There's no dereferencing. foo does nothing visible and can be
replaced by a NOP. For the call, no dereferencing required.
```
When you don't call `a.foo()` a dereference, you basically say
Again, no dereferencing for a (final) function call. `a.foo()` is
the same thing as `foo(a)` by reverse UFCS. The generated code is
identical. It is only the compiler that will use different
mangled names.
that `this` is allowed to be `null` inside a class member
function. (and then it'd have to be normal to do `if (this)
...` inside class member functions...)
These discussions are hard to do on a mailinglist, so I'll stop
here. Until next time at DConf, I suppose... ;-)
-Johan
[*] intentionally didn't say where those local variables _are_
stored, so that people can solve that little puzzle for
themselves ;-)
Re: signed nibble
On Monday, 7 January 2019 at 18:56:17 UTC, H. S. Teoh wrote: On Mon, Jan 07, 2019 at 06:42:13PM +, Patrick Schluter via Digitalmars-d-learn wrote: On Monday, 7 January 2019 at 17:23:19 UTC, Michelle Long wrote: > Is there any direct way to convert a signed nibble in to a > signed byte with the same absolute value? Obviously I can do > some bit comparisons but just curious if there is a very > quick way. byte b = nibble | ((nibble & 0x40)?0xF0:0); This is equivalent to doing a bit comparison (implied by the ? operator). You can do it without a branch: cast(byte)(nibble << 4) >> 4 will use the natural sign extension of a (signed) byte to "stretch" the upper bit. It just takes 2-3 CPU instructions. Yeah, my bit-fiddle-fu goes back to pre-barrel-shifter days. Up to 32 bit processors, shifting was more expensive than branching.
Re: signed nibble
On Monday, 7 January 2019 at 20:28:21 UTC, H. S. Teoh wrote: On Mon, Jan 07, 2019 at 08:06:17PM +, Patrick Schluter via Digitalmars-d-learn wrote: On Monday, 7 January 2019 at 18:56:17 UTC, H. S. Teoh wrote: > On Mon, Jan 07, 2019 at 06:42:13PM +0000, Patrick Schluter > via Digitalmars-d-learn wrote: [...] > > byte b = nibble | ((nibble & 0x40)?0xF0:0); > > This is equivalent to doing a bit comparison (implied by the > ? operator). You can do it without a branch: > > cast(byte)(nibble << 4) >> 4 > > will use the natural sign extension of a (signed) byte to > "stretch" the upper bit. It just takes 2-3 CPU instructions. > Yeah, my bit-fiddle-fu goes back to pre-barrel-shifter days. Up to 32 bit processors, shifting was more expensive than branching. Really? Haha, never knew that, even though I date all the way back to writing assembly on 8-bit processors. :-D Most of my career was programming for 80186. Shifting by one was 2 cycles in register and 15 in memory. Shifting by 4, 9 cycles for regs/21 for mem. And 80186 was a fast shifter compared to 8088/86 or 68000 (8+2n cycles).
Re: signed nibble
On Monday, 7 January 2019 at 18:47:04 UTC, Adam D. Ruppe wrote: On Monday, 7 January 2019 at 18:42:13 UTC, Patrick Schluter wrote: byte b = nibble | ((nibble & 0x40)?0xF0:0); don't you mean & 0x80 ? He asked for signed nybble. So mine is wrong and yours also :-) It's obviously 0x08 for the highest bit of the low nybble. byte b = nibble | ((nibble & 0x08)?0xF0:0);
Re: signed nibble
On Monday, 7 January 2019 at 17:23:19 UTC, Michelle Long wrote: Is there any direct way to convert a signed nibble in to a signed byte with the same absolute value? Obviously I can do some bit comparisons but just curious if there is a very quick way. byte b = nibble | ((nibble & 0x40)?0xF0:0);
Re: Bitwise rotate of integral
On Tuesday, 8 January 2019 at 12:35:16 UTC, H. S. Teoh wrote: On Tue, Jan 08, 2019 at 09:15:09AM +, Patrick Schluter via Digitalmars-d-learn wrote: On Monday, 7 January 2019 at 23:20:57 UTC, H. S. Teoh wrote: [...] > [...] Are you sure it's dmd looking for the pattern. Playing with the godbolt link shows that dmd doesn't generate the rol code (gdc 4.8.2 neither). I vaguely remember a bug about this. There is definitely explicit checking for this in dmd; I don't remember if it was a bug in the pattern matching code itself, or some other problem, that made it fail. You may need to specify -O for the code to actually be active. Walter could point you to the actual function that does this optimization. I did use the -O flag. The code generated did not use rol.
Re: signed nibble
On Tuesday, 8 January 2019 at 10:32:25 UTC, Ola Fosheim Grøstad wrote: On Tuesday, 8 January 2019 at 09:30:14 UTC, Patrick Schluter wrote: [...] Heh, I remember they had a friday-night trivia contest at the mid-90s students pub (for natural sciences) where one of the questions was the opcode for 6502 LDA (or was it NOP?), and I believe I got it right. The opcode for NOP is burned into my memory as $EA was used for erasing code during debugging in a monitor. And it was also the letters for the big game company Electronic Arts... The cycle counts for 6502 are pretty easy though as they tend to be related to the addressing mode and most of them are in the range 1-5... No instruction for multiplication or division... Oh the fun... 2-7 cycles ;-)
Re: Bitwise rotate of integral
On Monday, 7 January 2019 at 23:20:57 UTC, H. S. Teoh wrote: On Mon, Jan 07, 2019 at 11:13:37PM +, Guillaume Piolat via Digitalmars-d-learn wrote: On Monday, 7 January 2019 at 14:39:07 UTC, Per Nordlöw wrote: > What's the preferred way of doing bitwise rotate of an > integral value in D? > > Are there intrinsics for bitwise rotation available in LDC? Turns out you don't need any: https://d.godbolt.org/z/C_Sk_- Generates ROL instruction. There's a certain pattern that dmd looks for, that it transforms into a ROL instruction. Similarly for ROR. Deviate too far from this pattern, though, and it might not recognize it as it should. To be sure, always check the disassembly. Are you sure it's dmd looking for the pattern. Playing with the godbolt link shows that dmd doesn't generate the rol code (gdc 4.8.2 neither).
Re: signed nibble
On Monday, 7 January 2019 at 21:46:21 UTC, H. S. Teoh wrote: On Mon, Jan 07, 2019 at 08:41:32PM +, Patrick Schluter via Digitalmars-d-learn wrote: On Monday, 7 January 2019 at 20:28:21 UTC, H. S. Teoh wrote: > On Mon, Jan 07, 2019 at 08:06:17PM +0000, Patrick Schluter > via Digitalmars-d-learn wrote: [...] > > Up to 32 bit processors, shifting was more expensive than > > branching. > > Really? Haha, never knew that, even though I date all the > way back to writing assembly on 8-bit processors. :-D > Most of my career was programming for 80186. Shifting by one was 2 cycles in register and 15 in memory. Shifting by 4, 9 cycles for regs/21 for mem. And 80186 was a fast shifter compared to 8088/86 or 68000 (8+2n cycles). I used to hack 6502 assembly code. Yeah, that's also what I started with, on the Apple II in the early 80s. I was quite surprized that my 6502 knowledge came in very handy when we worked on dial-in modems in the late 90s as the Rockwell modems all used 6502 derived micro-controllers for them. During the PC revolution I wrote an entire application in 8088 assembly. Used to know many of the opcodes and cycle counts by heart like you do, but it's all but a faint memory now. I had to lookup the exact cycle counts ;-) . I remember the relative costs, more or less, but not the details anymore.
Re: D is helping from porch pirates
On Wednesday, 19 December 2018 at 08:02:41 UTC, Piotrek wrote: On Monday, 17 December 2018 at 23:13:18 UTC, Daniel Kozák wrote: https://gma.abc/2zWvXCl D supports the bright side of life ;) That's a good spirit. Thanks for sharing. Cheers, Piotrek I found that approach more fun https://www.youtube.com/watch?v=xoxhDk-hwuo
Re: Bug in shifting
On Tuesday, 18 December 2018 at 20:33:43 UTC, Rainer Schuetze
wrote:
On 14/12/2018 02:56, Steven Schveighoffer wrote:
On 12/13/18 7:16 PM, Michelle Long wrote:
byte x = 0xF;
ulong y = x >> 60;
Surely you meant x << 60? As x >> 60 is going to be 0, even
with a ulong.
It doesn't work as intuitive as you'd expect:
void main()
{
int x = 256;
int y = 36;
int z = x >> y;
writeln(z);
}
prints "16" without optimizations and "0" with optimizations.
This happens for x86 architecture because the processor just
uses the lower bits of the shift count. It is probably the
reason why the language disallows shifting by more bits than
the size of the operand.
Yes. On x86 shifting (x >> y) is in reality x >> (y & 0x1F) on 32
bits and x >> (y & 0x3F) on 64 bits.
Re: Any easy way to extract files to memory buffer?
On Monday, 18 March 2019 at 23:40:02 UTC, Michelle Long wrote: On Monday, 18 March 2019 at 23:01:27 UTC, H. S. Teoh wrote: On Mon, Mar 18, 2019 at 10:38:17PM +, Michelle Long via Digitalmars-d-learn wrote: On Monday, 18 March 2019 at 21:14:05 UTC, Vladimir Panteleev wrote: > On Monday, 18 March 2019 at 21:09:55 UTC, Michelle Long > wrote: > > Trying to speed up extracting some files that I first > > have to extract using the command line to files then read > > those in... > > > > Not sure what is taking so long. I imagine windows caches > > the extraction so maybe it is pointless? [...] Why not just use std.mmfile to memory-map the file into memory directly? Let the OS take care of actually paging in the file data. T The files are on disk and there is an external program that read them and converts them and then writes the converted files to disk then my program reads. Ideally the conversion program would take memory instead of disk files but it doesn't. the file that was written by the first program will be in the file cache. mmap() (and the Windows equivalent of that) syscalls are at the core only giving access to the OS file cache. This means that std.mmfile is the way to go. There will be no reloading from disk if the file sizes are within reason.
Re: Should D file end with newline?
On Wednesday, 13 February 2019 at 05:13:12 UTC, sarn wrote: On Tuesday, 12 February 2019 at 20:03:09 UTC, Jonathan M Davis wrote: So, I'd say that it's safe to say that dmd The whole thing just seems like a weird requirement that really shouldn't be there, Like I said in the first reply, FWIW, it's a POSIX requirement. Turns out most tools don't care (and dmd is apparently one of them). If you want an easy counterexample, try the wc command (it miscounts lines for non-compliant files). I've never seen that break an actual build system, which is why I said you could mostly get away with it. On the other hand, being POSIX-compliant always works. it matters even less if text editors are automatically appending newlines to files if they aren't there whether they show them or not, since if that's the case, you'd have to really work at it to have files not ending with newlines anyway. There are definitely broken text editors out there that won't add the newline (can't think of names). Like Jacob Carlborg said, Github flags the files they generate. hexdump shows a newline followed by a null character followed by a newline after the carriage return. hexdump is printing little-endian 16b by default, so I think that's just two newlines followed by a padding byte from hexdump. Try using the -c or -b flag and you probably won't see any null byte. Curiously, if I create a .cpp or .c file with vim and have it end with a curly brace, vim _does_ append a newline followed by a null character followed by a newline at the end of the file. So, I guess that vim looks at the extension and realizes that C/C++ has such a requirement and takes care of it for you, but it does not think that .d files need them and adds nothing extra for them. It doesn't add anything for a .txt file when I tried it either. Are you sure? vim is supposed to add the newline for all text files because that's POSIX. It does on my (GNU/Linux) machine. A lots of fgets() based tools on Unix systems fail to read the last line if it doesn't contain a line feed character at the end. Afaicr glibc implementation does not have that problem but a lot of other standard C libs do. When we were still on Solaris we had to be very careful with that, as strange things could happen when using sed, awk, wc and a lot of other standard Unix commands. Now that we have switched to Linux we don't have the issue anymore.
Re: [OT] Re: 1 - 17 ms, 553 ╬╝s, and 1 hnsec
On Tuesday, 21 May 2019 at 02:12:10 UTC, Les De Ridder wrote:
On Sunday, 19 May 2019 at 12:24:28 UTC, Patrick Schluter wrote:
On Saturday, 18 May 2019 at 21:05:13 UTC, Les De Ridder wrote:
On Saturday, 18 May 2019 at 20:34:33 UTC, Patrick Schluter
wrote:
* hurrah for French keyboard which has a rarely used µ key,
but none for Ç a frequent character of the language.
That's the lowercase ç. The uppercase Ç is not directly
composable,
No, note that I said and not . Using Lock> it
outputs a 'Ç' for me (at least on X11 with the French layout).
Does not work on Windows. and it gives 9. I tested
also on my Linux Mint box and it output lowercase ç with lock>.
There are 2 other characters that are not available on the
french keyboard: œ and Œ. Quite annoying if you sell beef
(bœuf) and eggs (œufs) in the towns of Œutrange or Œting.
It seems those are indeed not on the French layout at all.
Might I
suggest using the Belgian layout? It is AZERTY too and has both
'œ'
and 'Œ'.
No, it hasn't.
I indeed prefer the Belgian keyboard. It has more composable
deadkey characters accents, tildas. Brackets [{]} and other
programming characters < > | etc, are better placed than on the
French keyboard.
Btw æ and Æ are missing also, but there it's not very important
as there are really only very few words in French that use them
ex-æquo, curriculum vitæ, et cætera
Re: 1 - 17 ms, 553 ╬╝s, and 1 hnsec
On Thursday, 16 May 2019 at 15:19:03 UTC, Alex wrote: 1 - 17 ms, 553 ╬╝s, and 1 hnsec That's µs* for micro-seconds. * hurrah for French keyboard which has a rarely used µ key, but none for Ç a frequent character of the language. WTH!! is there any way to just get a normal u rather than some fancy useless asci hieroglyphic? Why don't we have a fancy M? and an h? What's an hnsec anyways?
[OT] Re: 1 - 17 ms, 553 ╬╝s, and 1 hnsec
On Saturday, 18 May 2019 at 21:05:13 UTC, Les De Ridder wrote: On Saturday, 18 May 2019 at 20:34:33 UTC, Patrick Schluter wrote: * hurrah for French keyboard which has a rarely used µ key, but none for Ç a frequent character of the language. That's the lowercase ç. The uppercase Ç is not directly composable, annoying or to say it in French to illsutrate: "Ça fait chier". I use Alt+1+2+8 on Windows, but most people do not know these ancient OEM-437 based character codes going back to the orignal IBM-PC. The newer ANSI based Alt+0+1+9+9 is one keypress longer and I would have to learn actually the code. There are 2 other characters that are not available on the french keyboard: œ and Œ. Quite annoying if you sell beef (bœuf) and eggs (œufs) in the towns of Œutrange or Œting.
Re: Compile time mapping
On Saturday, 11 May 2019 at 15:48:44 UTC, Bogdan wrote:
What would be the most straight-forward way of mapping the
members of an enum to the members of another enum (one-to-one
mapping) at compile time?
An example of a Initial enum that creates a derived enum using
the same element names but applying a transformation via a
function foo() pus adding some other enum elements in the Derived
one not present in the Initial.
It's a little bit clumsy but works very well.
I use this at module level. This allows to have the Derived enum
at compile time so that it can be used to declare variables or
functions at compile time.
mixin({
string code = "enum Derived : ulong { "~
"init = 0,"; /* We set the dummy
init value to 0 */
static foreach(i; __traits(allMembers, Initial)) {
code ~= i~"= foo(Initial."~i~"),";
}
code ~= "
ALL= Whatever,
THING = 42,
return code ~ "}";
}());
Re: Why are immutable array literals heap allocated?
On Thursday, 4 July 2019 at 10:56:50 UTC, Nick Treleaven wrote:
immutable(int[]) f() @nogc {
return [1,2];
}
onlineapp.d(2): Error: array literal in `@nogc` function
`onlineapp.f` may cause a GC allocation
This makes dynamic array literals unusable with @nogc, and adds
to GC pressure for no reason. What code would break if dmd used
only static data for [1,2]?
int[] in D is not an array but a fat pointer. When one realizes
that then it become quite obvious why [1,2] was allocated. There
is somewhere in the binary a static array [1,2] but as it is
assigned to a pointer to mutable data, the compiler has no choice
as to allocate a mutable copy of that immutable array.
Re: Why are immutable array literals heap allocated?
On Friday, 5 July 2019 at 23:08:04 UTC, Patrick Schluter wrote:
On Thursday, 4 July 2019 at 10:56:50 UTC, Nick Treleaven wrote:
immutable(int[]) f() @nogc {
return [1,2];
}
onlineapp.d(2): Error: array literal in `@nogc` function
`onlineapp.f` may cause a GC allocation
This makes dynamic array literals unusable with @nogc, and
adds to GC pressure for no reason. What code would break if
dmd used only static data for [1,2]?
int[] in D is not an array but a fat pointer. When one realizes
that then it become quite obvious why [1,2] was allocated.
There is somewhere in the binary a static array [1,2] but as it
is assigned to a pointer to mutable data, the compiler has no
choice as to allocate a mutable copy of that immutable array.
and it cannot optimize it away because it doesn't know what the
caller want to do with it. It might in another module invoke it
and modify it, the compiler cannot tell. auto a=f(); a[0]++;
Re: Is there a way to slice non-array type in @safe?
On Thursday, 11 July 2019 at 19:35:50 UTC, Stefanos Baziotis wrote: On Thursday, 11 July 2019 at 18:46:57 UTC, Paul Backus wrote: Casting from one type of pointer to another and slicing a pointer are both @system, by design. Yes, I'm aware, there are no pointers in the code. The pointer was used here because it was the only way to solve the problem (but not in @safe). What's the actual problem you're trying to solve? There may be a different way to do it that's @safe. I want to make an array of bytes that has the bytes of the value passed. For example, if T = int, then I want an array of 4 bytes that has the 4 individual bytes of `s1` let's say. For long, an array of 8 bytes etc. Ideally, that would work with `ref` (i.e. the bytes of where the ref points to). imho this cannot be safe on 1st principle basis. You gain access to the machine representation of variable, which means you bypass the "control" the compiler has on its data. Alone the endianness issue is enough to have different behaviour of your program on different implementations. While in practice big endian is nearly an extinct species (, it is still enough to show why that operation is inherently @system and should not be considered @safe. Of course, a @trusted function can be written to take care of that, but that's in fact exactly the case as it should be.
Re: Why are immutable array literals heap allocated?
On Saturday, 6 July 2019 at 09:56:57 UTC, ag0aep6g wrote:
On 06.07.19 01:12, Patrick Schluter wrote:
On Friday, 5 July 2019 at 23:08:04 UTC, Patrick Schluter wrote:
On Thursday, 4 July 2019 at 10:56:50 UTC, Nick Treleaven
wrote:
immutable(int[]) f() @nogc {
return [1,2];
}
[...]
and it cannot optimize it away because it doesn't know what
the caller want to do with it. It might in another module
invoke it and modify it, the compiler cannot tell. auto a=f();
a[0]++;
f returns immutable. typeof(a) is immutable(int[]). You can't
do a[0]++.
You're right, I shouldn't post at 1 am.
DWT doesn't compile with dmd 2.87.0
DWT doesn't build anymore with the new compiler. Wasn't DWT supposed to be part of the build job of compiler so that regressions are caught in time? dwt 1.0.1+swt-3.4.1: building configuration "windows-win32"... C:\Users\Patri\AppData\Local\dub\packages\dwt-1.0.1_swt-3.4.1\dwt\org.eclipse.swt.win32.win32.x86\src\org\eclipse\swt\internal\gdip\Gdip.d(478,9): Deprecation: The delete keyword has been deprecated. Use object.destroy() (and core.memory.GC.free() if applicable) instead. C:\Users\Patri\AppData\Local\dub\packages\dwt-1.0.1_swt-3.4.1\dwt\org.eclipse.swt.win32.win32.x86\src\org\eclipse\swt\ole\win32\OleControlSite.d(886,43): Error: class `org.eclipse.swt.ole.win32.OleControlSite.OleControlSite` member AddRef is not accessible C:\Users\Patri\AppData\Local\dub\packages\dwt-1.0.1_swt-3.4.1\dwt\org.eclipse.swt.win32.win32.x86\src\org\eclipse\swt\ole\win32\OleControlSite.d(906,43): Error: class `org.eclipse.swt.ole.win32.OleControlSite.OleControlSite` member AddRef is not accessible C:\Users\Patri\AppData\Local\dub\packages\dwt-1.0.1_swt-3.4.1\dwt\org.eclipse.swt.win32.win32.x86\src\org\eclipse\swt\widgets\IME.d(506,29): Deprecation: The delete keyword has been deprecated. Use object.destroy() (and core.memory.GC.free() if applicable) instead. C:\D\dmd2\windows\bin\dmd.exe failed with exit code 1.
Re: How to debug long-lived D program memory usage?
On Thursday, 18 April 2019 at 12:00:10 UTC, ikod wrote: On Wednesday, 17 April 2019 at 16:27:02 UTC, Adam D. Ruppe wrote: D programs are a vital part of my home computer infrastructure. I run some 60 D processes at almost any time and have recently been running out of memory. I usually run program under valgrind in this case. Though it will not help you to debug GC problems, but will cut off memory leaked malloc-s. Even valgrind tool=massif ?
Re: DMD different compiler behaviour on Linux and Windows
On Thursday, 25 April 2019 at 20:18:28 UTC, Zans wrote:
import std.stdio;
void main()
{
char[] mychars;
mychars ~= 'a';
long index = 0L;
writeln(mychars[index]);
}
Why would the code above compile perfectly on Linux (Ubuntu
16.04), however it would produce the following error on Windows
10:
source\app.d(8,21): Error: cannot implicitly convert expression
index of type long to uint
On both operating systems DMD version is 2.085.0.
The issue here is not Windows vs Linux but 32 bits vs 64 bits.
On 32 bits architectures size_t is defined as uint, long being 64
bits long, conversion from long to uint is a truncating cast
which are not allowed implicitely in D.
It is unfortunate that the D compiler on Windows is still
delivered by default as a 32 bits binary and generating 32 bits
code. I think the next release will start to deliver the compiler
as 64 bits binary and generating 64 bits code.
Re: How should I sort a doubly linked list the D way?
On Tuesday, 13 August 2019 at 18:28:35 UTC, Ali Çehreli wrote: On 08/13/2019 10:33 AM, Mirjam Akkersdijk wrote: > On Tuesday, 13 August 2019 at 14:04:45 UTC, Sebastiaan Koppe wrote: >> Convert the nodes into an D array, sort the array with nodes.sort!"a.x >> < b.x" and then iterate the array and repair the next/prev pointers. If possible, I would go further and ditch the linked list altogether: Just append the nodes to an array and then sort the array. It has been shown in research, conference presentations, and in personal code to be the fasted option is most (or all) cases. > doesn't the nature of the dynamic array slow it down a bit? Default bounds checking is going to cost a tiny bit, which you can turn off after development with a compiler flag. (I still wouldn't.) The only other option that would be faster is an array that's sitting on the stack, created with alloca. But it's only for cases where the thread will not run out of stack space and the result of the array is not going to be used. > can't I define an array of fixed size, which is dependent on the input > of the function? arr.length = number_of_elements; All elements will be initialized to the element's default value, which happens to be null for pointers. (If we are back to linked list Node pointers.) However, I wouldn't bother with setting length either as the cost of automatic array resizing is amortized, meaning that it won't hurt the O(1) algorithmic complexity in the general case. In the GC case that D uses, it will be even better: because if the GC knowns that the neighboring memory block is free, it will just add that to the dynamic array's capacity without moving elements to the new location. Summary: Ditch the linked list and put the elements into an array. :) There are mainly three reasons why arrays are nowadays faster than double linked lists: - pointer chasing can difficultly be paralized and defeats prefetching. Each pointer load may cost the full latency to memory (hundreds of cycles). In a multiprocessor machine may also trigger a lot of coherency trafic. - on 64 bit systems 2 pointers cost 16 bytes. If the payload is small, there is more memory used in the pointer than in the data. - when looping in an array the OO machinery will be able to parallelize execution beyond loop limits. - reduced allocation, i.e. allocation is done in bulk => faster GC for D. It is only when there are a lot of external references to the payload in the list that using an array may become too unwieldy, i.e. if moving an element in memory requires the update of other pointers outside of the list.
Re: Silicon Valley C++ Meetup - August 28, 2019 - "C++ vs D: Let the Battle Commence"
On Tuesday, 27 August 2019 at 19:23:41 UTC, Ali Çehreli wrote: I will be presenting a comparison of D and C++. RSVP so that we know how much food to order: https://www.meetup.com/ACCU-Bay-Area/events/263679081/ It will not be streamed live but some people want to record it; so, it may appear on YouTube soon. As always, I have way too many slides. :) The contents are - Introduction - Generative programming with D - Thousand cuts of D - C++ vs. D - Soapboxing Really a pitty that the audio is really, really bad. It's interesting enough to put up with it, but I had to crank up the knob to 11 to barely be able to ujnderstand what you were saying.
Re: Template specialized functions creating runtime instructions?
On Wednesday, 21 August 2019 at 00:11:23 UTC, ads wrote: On Wednesday, 21 August 2019 at 00:04:37 UTC, H. S. Teoh wrote: On Tue, Aug 20, 2019 at 11:48:04PM +, ads via Digitalmars-d-learn wrote: [...] 2) Deducing the string as you describe would require CTFE (compile-time function evaluation), which usually isn't done unless the result is *required* at compile-time. The typical way to force this to happen is to store the result into an enum: enum myStr = fizzbuzz!...(...); writeln(myStr); Since enums have to be known at compile-time, this forces CTFE evaluation of fizzbuzz, which is probably what you're looking for here. T Thank you for clearing those up. However even if I force CTFE (line 35), it doesn't seem to help much. https://godbolt.org/z/MytoLF It does. on line 4113 you have that string .L.str: .asciz "Buzz\n49\nFizz\n47\n46\nFizzBuzz\n44\n43\nFizz\n41\nBuzz\nFizz\n38\n37\nFizz\nBuzz\n34\nFizz\n32\n31\nFizzBuzz\n29\n28\nFizz\n26\nBuzz\nFizz\n23\n22\nFizz\nBuzz\n19\nFizz\n17\n16\nFizzBuzz\n14\n13\nFizz\n11\nBuzz\nFizz\n8\n7\nFizz\nBuzz\n4\nFizz\n2\n1\n" and all main() does is call writeln with that string _Dmain: pushrax lea rsi, [rip + .L.str] mov edi, 203 call@safe void std.stdio.writeln!(immutable(char)[]).writeln(immutable(char)[])@PLT xor eax, eax pop rcx ret You haven't given instruction to the linker to strip unused code so the functions generated by the templates are still there.
Re: Question about ubyte x overflow, any safe way?
On Monday, 5 August 2019 at 18:21:36 UTC, matheus wrote: On Monday, 5 August 2019 at 01:41:06 UTC, Ali Çehreli wrote: ... Two examples with foreach and ranges. The 'ubyte.max + 1' expression is int. The compiler casts to ubyte (because we typed ubyte) in the foreach and we cast to ubyte in the range: ... Maybe it was a bad example of my part (Using for), and indeed using foreach would solve that specific issue, but what I'm really looking for if there is a flag or a way to check for overflow when assigning some variable. ubyte u = 260; // Here should be given some warning or throw exception. It's ubyte, but it could be any other data type. Yes, no question. It's checkedint that you should use. It was written exactly for that purpose.
Re: Blog series to teach and show off D's metaprogramming by creating a JSON serialiser
On Sunday, 3 November 2019 at 21:35:18 UTC, JN wrote: On Sunday, 3 November 2019 at 08:37:07 UTC, SealabJaster wrote: On Sunday, 3 November 2019 at 08:35:42 UTC, SealabJaster wrote: On Friday, 1 November 2019 at 21:14:56 UTC, SealabJaster wrote: ... Sorry, seems it cut out the first half of that reply. New posts are out, and I don't want to spam Announce with new threads, so I'm just replying to this one. #1.1 https://bradley.chatha.dev/Home/Blog?post=JsonSerialiser1_1 #2 https://bradley.chatha.dev/Home/Blog?post=JsonSerialiser2 "This often seems to confuse people at first, especially those coming from other languages" I think what's confusing people is that enum (short for ENUMERATION) is suddenly used like a constant/alias. I don't get why it confuses people. In all languages I know (C, C++, Java, Pascal, etc..) they are used to associate a compile time symbols with some quantities, i.e. the definition of constants. When an enumeration only consists of 1 value, then the enumeration is this value itself.
Re: The Serpent Game Framework - Open Source!!
On Saturday, 29 February 2020 at 07:18:26 UTC, aberba wrote: On Thursday, 27 February 2020 at 22:29:41 UTC, aberba wrote: There's this ongoing open source game framework by Ikey. I knew him to be a diehard C guru (from the Solus Project) but is now rocking D, hence Serpent. [...] Ikey did an interview with Foss and he said something about why he uses D. It's interested and funny as well. Having done a lot of Go development, I started researching alternatives to C that were concurrency-aware, string-sane, and packed with a powerful cross-platform standard library. This is the part where everyone will automatically tell you to use Rust. Unfortunately, I’m too stupid to use Rust because the syntax literally offends my eyes. I don’t get it, and I never will. Rust is a fantastic language and as academic endeavours go, highly successful. Unfortunately, I’m too practically minded and seek comfort in C-style languages, having lived in that world too long. So, D was the best candidate to tick all the boxes, whilst having C & C++ interoptability. Pew! Pew!! Nailed it. https://itsfoss.com/ikey-doherty-serpent-interview/ from the article Unfortunately, I’m too stupid to use Rust because the syntax literally offends my eyes. I don’t get it, and I never will. Rust is a fantastic language and as academic endeavours go, highly successful. Unfortunately, I’m too practically minded and seek comfort in C-style languages, having lived in that world too long. So, D was the best candidate to tick all the boxes, whilst having C & C++ interoptability. That's exactly my sentiment too.
Re: FeedSpot Recognizes the GtkDcoding Blog
On Thursday, 6 February 2020 at 10:34:16 UTC, Ron Tarrant wrote: On Tuesday, 4 February 2020 at 22:23:33 UTC, Bastiaan Veelo wrote: Well done! Bastiaan. On Tuesday, 4 February 2020 at 19:11:48 UTC, M.M. wrote: Congratulations! Thanks, guys. I'm hoping this will help brighten the spotlight on the D language. TIOBE (https://archive.ph/E3Xu7) has D rising fast in popularity. If I can help in some small way to keep this momentum going, then I'm a cappy hamper. These are exactly the things that were a little bit missing in the D world. Usage of it and advertisement of its usage. Congrats for your blog.
Re: What kind of Editor, IDE you are using and which one do you like for D language?
On Sunday, 29 December 2019 at 14:41:46 UTC, Russel Winder wrote: On Sat, 2019-12-28 at 22:01 +, p.shkadzko via Digitalmars-d-learn wrote: […] p.s. I found it quite satisfying that D does not really need an IDE, you will be fine even with nano. The fundamental issue with these all battery included fancy IDE's (especially in Java) is that they tend to become dependencies of the projects themselves. How many times have I seen in my professionnal world, projects that required specific versions of Eclipse with specific versions of extensions and libraries? At my work we have exactly currently the problem. One developer wrote one of the desktop apps and now left the company. My colleagues of that department are now struggling to maintain the app as it used some specific GUI libs linked to some Eclipse version and they are nowhere to be found. You may object that it's a problem of the project management and I would agree. It was the management error to let the developer choose the IDE solution in the first place. A more classical/portable approach would have been preferable. Furthermore, it is extremely annoying that these IDE change over time and all the fancy stuff gets stale and changed with other stuff that gets stale after time. Visual Studio is one of the worst offenders in that category. Every 5 years it changes so much that everything learnt before can be thrown away. IDE's work well for scenarios that the developers of the IDE thought of. Anything a little bit different requires changes that are either impossible to model or require intimate knowledge of the functionning of the IDE. Visual Studio comes to mind again of an example where that is horribly painful (I do not even mention the difficulty to even install such behemoth programs on our corporate laptops which are behind stupid proxies and follow annoying corporate policy rules).
Re: What kind of Editor, IDE you are using and which one do you like for D language?
On Monday, 30 December 2019 at 14:59:22 UTC, bachmeier wrote:
On Monday, 30 December 2019 at 06:43:03 UTC, H. S. Teoh wrote:
[...]
Another way in which the IDE is "heavy" is the amount of
overhead for beginning/occasional users. I like that I can get
someone started using D like this:
1. Open text editor
2. Type simple program
3. Compile by typing a few characters into a terminal/command
prompt.
An IDE adds a crapload to the learning curve. It's terrible,
because they need to memorize a bunch of steps when they use a
GUI (click here -> type this thing in this box -> click here ->
...)
Back when I was teaching intro econ courses, which are taken by
nearly all students here, I'd sometimes be talking with
students taking Java or C++ courses. One of the things that
really sucked (beyond using Java for an intro programming
class) was that they'd have to learn the IDE first. Not only
were they hit with this as the simplest possible program:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World");
}
}
but before they even got there, the instructor went through an
entire lecture teaching them about the IDE. That's an effective
way to make students think programming is a mind-numbingly
stupid task on par with reading the phone book.
Contrast that with students opening a text editor, typing
`print "Hello World"` and then running the program.
IDE support should obviously be made available. I think it
would be a mistake, however, to move away from the simplicity
of being able to open a text editor, type in a few lines, and
then compile and run in a terminal. It's not just beginners.
This is quite handy for those who will occasionally work with D
code. For someone in my position (academic research), beginners
and occasional programmers represents most of the user base.
Good point. It also trains people to not be able to work without
IDE. I see it at work with some of the Java devs who aren't even
able to invoke javac in a command line and setting javapath
correctly. Why? Because IDE shielded them from these easy things.
It has also a corrolary that they're not capable to implement
sometimes simple protocols or file processings without resorting
to external libraries. A little bit like people needing even and
odd library in Javascript.
Re: CT regex in AA at compile time
On Tuesday, 7 January 2020 at 15:40:58 UTC, Taylor Hillegeist
wrote:
I'm trying to trick the following code snippet into compilation.
enum TokenType{
//Terminal
Plus,
Minus,
LPer,
RPer,
Number,
}
static auto Regexes =[
TokenType.Plus: ctRegex!(`^ *\+`),
TokenType.Minus: ctRegex!(`^ *\-`),
TokenType.LPer: ctRegex!(`^ *\(`),
TokenType.RPer: ctRegex!(`^ *\)`),
TokenType.Number: ctRegex!(`^ *[0-9]+(.[0-9]+)?`)
];
but I can't get it to work. it says its an Error: non-constant
expression.
I imagine this has to do with the ctRegex template or
something. maybe there is a better way? Does anyone know?
In that specific case: why don't you use an array indexed on
TokenType? TokenType are consecutive integrals so indexing is the
fastest possible access method.
Re: DConf 2020 Canceled
On Wednesday, 11 March 2020 at 20:30:12 UTC, Anonymous wrote: to all the people dogpiling the responses against Era's point of view: the reason there is not more dissent, whether here or in other respectable forums (eg scientific research in general), is purely because of social mechanics (ostracization of dissenters) - not the inherent unassailable truthfulness of the apparent consensus point of view. when contrary information is personally and professionally radioactive, is it a wonder nobody wants to associate themselves with it? but here, as in so many elsewheres, "this is not the place." I'm already pushing the boundary with this meta-post containing no specific assertions, and will almost certainly put Mike in the unfortunate position of having to put his foot down in this thread (sorry Mike). I'm just pointing out that, anywhere that people's real life identities are tied to what they are saying, there will be an artificial consensus around safe, socially sanctioned viewpoints. so you all essentially get an unrestricted platform to say "lol we're so informed and naysayers are tinfoil-hat nutters," but if somebody made a good-faith effort to respond to any of your points, messages would start getting deleted and the thread would be locked. and far from exceptional, that happens EVERYWHERE. I don't expect any of you /respectable, rational/ people to read it, but for the shy dissenters among us, here's a short little essay on the circularity of scientific peer review (I am not the author): https://www.reddit.com/r/accountt1234/comments/5umtip/scientific_circular_reasoning/ What, you're saying continents can move and that there's no phlogiston and no ether around? Dinosaurs did not gradually disappear and washing ones hands could avoid childbed fever? and that stomach ulcer are of bacierial origin? Heretic, to the pyre. More seriously: these were all examples of career killing "consensus scientific truths"™ that have been slowly showed to be not that truthful (after a lot of funerals). So, a little bit of caution on the consensus opinion is required, especially if that consensus enables billion/trillion big industries (global warming, pharmacology, etc.).
Re: How does one read file line by line / upto a specific delimeter of an MmFile?
On Monday, 16 March 2020 at 13:09:08 UTC, Adnan wrote:
On Sunday, 15 March 2020 at 00:37:35 UTC, H. S. Teoh wrote:
On Sat, Mar 14, 2020 at 10:37:37PM +, Adnan via
Digitalmars-d-learn wrote:
[...]
That's because a memory-mapped file appears directly in your
program's memory address space as if it was an array of bytes
(ubyte[]). No interpretation is imposed upon the contents.
If you want lines out of it, try casting the memory to
const(char)[] and using std.algorithm.splitter to get a range
of lines. For example:
auto mmfile = new MmFile("myfile.txt");
auto data = cast(const(char)[]) mmfile[];
auto lines = data.splitter("\n");
foreach (line; lines) {
...
}
T
Would it be wasteful to cast the entire content into a const
string? Can a memory mapped file be read with a buffer?
a string is the same thing as immutable(char)[] . It would make
no difference with the example above.
Re: Compilation memory use
On Monday, 4 May 2020 at 17:00:21 UTC, Anonymouse wrote: TL;DR: Is there a way to tell what module or other section of a codebase is eating memory when compiling? [...] maybe with the massif tool of valgrind?
String interpolation
https://forum.dlang.org/post/prlulfqvxrgrdzxot...@forum.dlang.org
On Tuesday, 10 November 2015 at 11:22:56 UTC, wobbles wrote:
int a = 1;
int b = 4;
writefln("The number %s is less than %s", a, b);
writeln("The number ",a, " is less than ",b);
Re: DIP1028 - Rationale for accepting as is
On Sunday, 24 May 2020 at 03:28:25 UTC, Walter Bright wrote: I'd like to emphasize: 1. It is not possible for the compiler to check any declarations where the implementation is not available. Not in D, not in any language. Declaring a declaration safe does not make it safe. 2. If un-annotated declarations cause a compile time error, it is highly likely the programmer will resort to "greenwashing" - just slapping @safe on it. I've greenwashed code. Atila has. Bruce Eckel has. We've all done it. Sometimes even for good reasons. 3. Un-annotated declarations are easily detectable in a code review. 4. Greenwashing is not easily detectable in a code review. 5. Greenwashing doesn't fix anything. The code is not safer. It's an illusion, not a guarantee. 6. If someone cares to annotate declarations, it means he has at least thought about it, because he doesn't need to. Hence it's more likely to be correct than when greenwashed. 7. D should *not* make it worthwhile for people to greenwash code. It is, in a not-at-all obvious way, safer for C declarations to default to being safe. Apparently, you're of the opinion it's better the compiler does the greenwashing. Got it!
Re: Symmetry Investments and the D Language Foundation are Hiring
On Wednesday, 2 September 2020 at 12:50:35 UTC, Steven Schveighoffer wrote: On 9/1/20 2:38 PM, Patrick Schluter wrote: On Tuesday, 1 September 2020 at 13:28:07 UTC, Steven Schveighoffer wrote: On 9/1/20 5:38 AM, Stefan Koch wrote: [...] I have to agree with Jacob -- what common situation is changing the timestamps of your files but not the data? git checkout branch git checkout - Is that a part of normal development process? Typically when I want incremental building, I'm editing a file, then rebuilding. I mean, you check out a different branch, but you don't want to rebuild everything? I would. And with D, where there are so many templates, almost everything is going to need rebuilding anyway. This update to dub might replace a build-time problem with a build inconsistency problem (hopefully linker error, but possibly code generation differences). Yes, it happens from time to time and on makefile based it involves recompilations of unchanged files but granted it could be just me.
Re: Symmetry Investments and the D Language Foundation are Hiring
On Tuesday, 1 September 2020 at 13:28:07 UTC, Steven Schveighoffer wrote: On 9/1/20 5:38 AM, Stefan Koch wrote: On Tuesday, 1 September 2020 at 09:09:36 UTC, Jacob Carlborg wrote: BTW, is timestamps vs SHA-1 hashing really the most pressing issue with Dub? We think that not recompiling certain modules which have not changed will improve our build times. And the task proposed is actually something that can go in without too much struggle. Whereas deeper issues in dub likely take much longer. I have to agree with Jacob -- what common situation is changing the timestamps of your files but not the data? git checkout branch git checkout -
Re: Why was new(size_t s) { } deprecated in favor of an external allocator?
On Wednesday, 14 October 2020 at 20:32:51 UTC, Max Haughton wrote: On Wednesday, 14 October 2020 at 20:27:10 UTC, Jack wrote: What was the reasoning behind this decision? Andrei's std::allocator talk from a few years ago at cppcon covers this (amongst other things) Yes, and what did he say? You seriously don't expect people to search for a random talk from a random event from a random year?
Re: Why is BOM required to use unicode in tokens?
On Wednesday, 16 September 2020 at 00:22:15 UTC, Steven Schveighoffer wrote: On 9/15/20 8:10 PM, James Blachly wrote: On 9/15/20 10:59 AM, Steven Schveighoffer wrote: [...] Steve: It sounds as if the spec is correct but the glyph (codepoint?) range is outdated. If this is the case, it would be a worthwhile update. Do you really think it would be rejected out of hand? I don't really know the answer, as I'm not a unicode expert. Someone should verify that the character you want to use for a symbol name is actually considered a letter or not. Using phobos to prove this is kind of self-defeating, as I'm pretty sure it would be in league with DMD if there is a bug. I checked, it's not a letter. None of the math symbols are. But if it's not a letter, then it would take more than just updating the range. It would be a change in the philosophy of what constitutes an identifier name.
Re: Rationale for accepting DIP 1028 as is
On Wednesday, 27 May 2020 at 10:46:11 UTC, Walter Bright wrote: On 5/27/2020 2:34 AM, Bastiaan Veelo wrote: On Wednesday, 27 May 2020 at 09:09:58 UTC, Walter Bright wrote: On 5/26/2020 11:20 PM, Bruce Carneal wrote: I'm not at all concerned with legacy non-compiling code of this nature. Apparently you agree it is not an actual problem. Really? I don't know if you really missed the point being made, or you're being provocative. Both seem unlikely to me. His argument was: "Currently a machine checked @safe function calling an unannotated extern C routine will error out during compilation. This is great as the C routine was not machine checked, and generally can not be checked. Post 1028, IIUC, the compilation will go through without complaint. This seems quite clear. What am I missing?" I replied that it was unlikely that such legacy code existed. He replied that he was not concerned about it. I.e. working legacy code is not going break. The legacy code is not the issue, never was. It always was about unsafe code that will become @safe with that DIP. Safe code is safe and DIP doesn't change that. It's all about UNSAFE code becoming magically labelled SAFE by the compiler but that is still UNSAFE in reality.
Re: DIP1028 - Rationale for accepting as is
On Tuesday, 26 May 2020 at 03:37:29 UTC, Walter Bright wrote: On 5/25/2020 7:04 PM, Johannes Loher wrote: [..] Do you honestly think option 1 is better? Yes, for reasons I carefully laid out. which fails to convince anyone because the reasoning is flawed. > no clues whatsoever He can look at unattributed declarations. The whole debate boils down to "is greenwashing better, more honest, more debuggable than leaving things unattributed?" No on all three accounts. Unattended automatic greenwashing by the compiler is WORSE!
Re: Getting Qte5 to work
On Wednesday, 28 October 2020 at 06:52:35 UTC, evilrat wrote: Just an advice, Qte5 isn't well maintained, the other alternatives such as 'dlangui' also seems abandoned, so basically the only maintained UI library here is gtk-d, but there was recently a nice tutorial series written about it. DWT is also still active. The looks are a little outdated as it is swt-3 based but works just fine.
Re: LDC 1.24.0-beta1
On Saturday, 24 October 2020 at 00:00:02 UTC, starcanopy wrote: On Friday, 23 October 2020 at 22:48:33 UTC, Imperatorn wrote: On Friday, 23 October 2020 at 20:21:39 UTC, aberba wrote: On Friday, 23 October 2020 at 18:01:19 UTC, Kagamin wrote: [...] Not saying Kinke SHOULD do it. Was rather disagreeing with the idea that "developers" don't use installers. And that's a shortcoming with the LDC project...no straightforward way to set it up on Windows using an installer. If visuald supports LDC, why not point people to it. [...] I agree with this. Not providing an installer gives the message that you're not that interested in people using it. That's an exaggeration. Every release is accompanied by binaries that one may easily retrieve. Setting up the dependencies is only done once, and if you're a Windows developer, such an environment most likely exists, and you'll likely only have to add the bin to your path. It's my understanding that there are few people regularly working on LDC; allocating (voluntary!) manpower to a nice but non-essential component doesn't seem wise. You underestimate how spoiled windows developer are. Even these simple step are completely out of character for most software on the platform. 20 years ago it wasn't a problem, now on Windows 10 it's a whole other story. How many clicks to get the dialog to set PATH? On NT4 it was 2 clicks, now on Windows 10 I still haven't figured out how to do it without searching like a madman. To make it short. The Windows platform is getting more and more hostile to manual tuning.
Re: Post: Why no one is using your D library
On Thursday, 2 July 2020 at 14:56:09 UTC, aberba wrote: Why no one is using your D library So I decided to write a little something special. Its my love letter to D folks. https://aberba.vercel.app/2020/why-no-one-is-using-your-d-library/ Thank you. Really good and I hope devs here will follow your advices. It's needed.
Re: Generating struct .init at run time?
On Thursday, 2 July 2020 at 07:51:29 UTC, Ali Çehreli wrote: Normally, struct .init values are known at compile time. Unfortunately, they add to binary size: [...] memset() is the function you want. The initializer is an element generated in the data segment (or in a read only segment) that will be copied to the variable by a internal call to memcpy. The same happens in C except that the compilers are often clever and replace the copy by a memset().
Re: "if not" condition check (for data validation)
On Thursday, 18 June 2020 at 13:58:33 UTC, Dukc wrote: On Thursday, 18 June 2020 at 13:57:39 UTC, Dukc wrote: if (not!(abra && cadabra)) ... if (not(abra && cadabra)) ... Which is a quite a complicated way to write if (!(abra && cadabra)) ...
Re: Talk by Herb Sutter: Bridge to NewThingia
On Monday, 29 June 2020 at 12:17:57 UTC, Russel Winder wrote: On Mon, 2020-06-29 at 10:31 +, IGotD- via Digitalmars-d-announce wrote: Another rant… …batteries included standard libraries are a thing of the 1990s and earlier. They are a reflection of pre-Internet thinking. You got a language distribution, and everything else was home grown. Now we have the Internet you can get libraries via download. Languages come with the minimal library needed to function and all else is gettable. Go, Rust, Python, and other languages have this (even though Python still has a batteries included standard library). C++ has moved on to this idea; Conan (or other system) hasn't really caught on in C++ circles. Ditto Fortran, still using pre-2000 thinking. And that is completely wrong headed. Internet is not always directly accessible. There are a lot of companies that restrict access to the Internet for their security sensible servers, intranets etc. University people often have no clue what is standard in the corporate or the public office world. To give an example from the EU Commission. A good portion of our servers are isolated on an Intranet with very restricted access to the Internet via proxys for which access has to be requested for to the IT service. Out Intranet is deployed over different sites in Europe but the trafic is not routed over the Internet but over specialized network reserved for public institutions in Europe. The few bridges to the Internet in that network are surveilled like Fort Knox. There are also special rooms throughout our premises that are not even connected to the Intranet. Building software for these special machines has become a real challenge nowadays. These security issues are not even the strictest I've seen or heard of here in Luxembourg with all its banking companies. No, Internet is not always as easy peasy and having a language that can live alone and provide quite a lot of features without always calling home is a good thing. That's why I always ranted several versions ago when Visual Studio was nearly forced upon the user. Visual Studio and all Microsoft stuff is extremely difficult to install with a poor Internet connection (the setup didn't even accept a proxy). Sorry, my rant.
Re: Talk by Herb Sutter: Bridge to NewThingia
On Monday, 29 June 2020 at 16:47:27 UTC, jmh530 wrote: On Monday, 29 June 2020 at 15:44:38 UTC, Patrick Schluter wrote: [snip] And that is completely wrong headed. +1 As much as I'm sympathetic to the arguments for a slim standard library, the amount of problems I've had in a corporate setting trying to get libraries installed behind firewalls/proxies makes me glad for the larger one. Until a few years ago, I had to manually download every R library and every single one of their dependencies and manage them myself. It's one reason I really like run.dlang.org. I've never had a problem with it. Of course, I see nothing wrong with a high bar for entry into the standard library or the sort of promotion/relegation-type approach I've heard on the forums. All packages I install on our Linux servers, I have to compile them by source. All the default paths used by the packages are readonly. So, everything with prefix, all dependencies. The machine with an outdated gcc (4.4.7). In that configuration, it is impossible to build a recent dmd. Fortunately I managed to get an alternative proxy access that managed to download the bootstrap d compiler.
Re: where is the memory corruption?
On Wednesday, 9 December 2020 at 21:28:04 UTC, Paul Backus wrote: On Wednesday, 9 December 2020 at 21:21:58 UTC, ag0aep6g wrote: D's wchar is not C's wchar_t. D's wchar is 16 bits wide. The width of C's wchar_t is implementation-defined. In your case it's probably 32 bits. In D, C's wchar_t is available as `core.stdc.stddef.wchar_t`. http://dpldocs.info/experimental-docs/core.stdc.stddef.wchar_t.1.html Don't use wchar_t in C. It has variable size depending of implementation. On Posix machines (Linux, BSD etc.) it's 32 bit wide UTF-32, on Windows it 16 bit UTF-16.
Re: Return values from auto function
On Saturday, 7 November 2020 at 15:49:13 UTC, James Blachly wrote:
```
retval = i > 0 ? Success!int(i) : Failure("Sorry");
```
casting each to `Result` compiles, but is verbose:
```
return i > 0 ? cast(Result) Success!int(i) : cast(Result)
Failure("Sorry");
```
** Could someone more knowledgeable than me explain why
implicit conversion does not happen with the ternary op, but
works fine with if/else? Presumably, it is because the op
returns a single type and implicit conversion is performed
after computing the expression's return type? If this somehow
worked, it would make the SumType package much more ergonomic **
It's just that tenary requires the same type in both branches. It
was already so in C.
return i > 0 ? (retval = Success!int(i)) : (retval =
Failure("Sorry"));
should work
Re: why `top` report is not consistent with the memory freed by core.stdc.stdlib : free?
On Friday, 6 November 2020 at 06:17:42 UTC, mw wrote: Hi, I'm trying this: https://wiki.dlang.org/Memory_Management#Explicit_Class_Instance_Allocation using core.stdc.stdlib : malloc and free to manually manage memory, I tested two scenarios: -- malloc & free -- malloc only and I use Linux command `top` to check the memory used by the program, there is no difference in this two scenarios. I also tried to use `new` to allocate the objects, and GC.free(). The memory number reported by `top` is much less than those reported by using core.stdc.stdlib : malloc and free. I'm wondering why? shouldn't core.stdc.stdlib : malloc and free be more raw (low-level) than new & GC.free()? why `top` shows stdlib free() is not quite working? stdlib free does not give memory back to the system in a process normally on Linux. top only shows the virtual memory granted to that process. When you malloc, the VIRT goes up, the RES might go up also but they only go down if explicitly requested.
Re: Discussion Thread: DIP 1039--Static Arrays with Inferred Length--Community Review Round 1
On Wednesday, 6 January 2021 at 14:03:14 UTC, Mathias LANG wrote: On Wednesday, 6 January 2021 at 13:48:52 UTC, angel wrote: On Wednesday, 6 January 2021 at 09:24:28 UTC, Mike Parker wrote: The Feedback Thread is here: https://forum.dlang.org/post/qglydztoqxhhcurvb...@forum.dlang.org Why not "int[auto] arr = [1, 2, 3]" ? IMHO auto keyword is less ambiguous than $. Someone else could misunderstand `auto` to mean partial type deduction on associative array, e.g. `int[auto] arr = ["Hello": ubyte(1), "World": ubyte(2)];`. Personally, I think `$` is very natural here, but I also didn't consider `auto` before. $ is very much appropriate imho, as it implies the length of the array. auto suggests a type (or storage class) and has only barely a link with arrays.
Re: Shutdown signals
On Tuesday, 11 May 2021 at 06:44:57 UTC, Tim wrote: On Monday, 10 May 2021 at 23:55:18 UTC, Adam D. Ruppe wrote: [...] I don't know why I didn't find that. I was searching for the full name, maybe too specific? Thanks anyways, this is super helpful. I wish it was documented better though :( So why use sigaction and not signal? From what I can tell signal is the C way of doing things Use `sigaction()`, `signal()` has problems. See this stackoverflow [1] question explains the details [1]: https://stackoverflow.com/questions/231912/what-is-the-difference-between-sigaction-and-signal
Re: Recommendations on avoiding range pipeline type hell
On Sunday, 16 May 2021 at 09:55:31 UTC, Chris Piker wrote:
On Sunday, 16 May 2021 at 09:17:47 UTC, Jordan Wilson wrote:
Another example:
```d
auto r = [iota(1,10).map!(a => a.to!int),iota(1,10).map!(a =>
a.to!int)];
# compile error
```
Hi Jordan
Nice succinct example. Thanks for looking at the code :)
So, honest question. Does it strike you as odd that the exact
same range definition is considered to be two different types?
Even in C
```
typedef struct {
int a;
} type1;
```
and
```
struct {
int a;
} type2;
```
are two different types. The compiler will give an error if you
pass one to a function waiting for the other.
```
void fun(type1 v)
{
}
type2 x;
fun(x); // gives error
```
See https://godbolt.org/z/eWenEW6q1
Maybe that's eminently reasonable to those with deep knowledge,
but it seems crazy to a new D programmer. It breaks a general
assumption about programming when copying and pasting a
definition yields two things that aren't the same type. (except
in rare cases like SQL where null != null.)
On a side note, I appreciate that `.array` solves the problem,
but I'm writing pipelines that are supposed to work on
arbitrarily long data sets (> 1.4 TB is not uncommon).
Re: wanting to try a GUI toolkit: needing some advice on which one to choose
On Tuesday, 1 June 2021 at 20:56:05 UTC, someone wrote: On Tuesday, 1 June 2021 at 16:20:19 UTC, Ola Fosheim Grøstad wrote: [...] I wasn't considering/referring to content in the browser, this is an entirely different arena. [...] Thank you! I can only agree.
Re: News Roundup on the D Blog
On Friday, 26 March 2021 at 10:21:01 UTC, drug wrote: On 3/26/21 12:52 PM, Martin Tschierschke wrote: The view reader comments are all negative about D. What exactly? Tango vs Phobos? GC? Or something reasonable? No, just the typical know-it-alls w.nkers the heise-forum are full of.
Re: Endianness - How to test code for portability
On Friday, 12 March 2021 at 05:53:40 UTC, Preetpal wrote: In the portability section of the language spec, they talk about endianness (https://dlang.org/spec/portability.html#endianness) which refers "to the order in which multibyte types are stored." IMO if you wanted to actually be sure your code is portable across both big endian and little endian systems, you should actually run your code on both types of systems and test if there any issues. The problem is that I am not aware of any big-endian systems that you can actually test on and if there is any D lang compiler support for any of these systems if they exist. This is not an important issue to me but I was just curious to see if anyone actually tests for portability issues related to endianness by compiling their D Lang code for a big endian architecture and actually running it on that system. Actual big endian systems? Not many around anymore: - SPARC almost dead - IBM z/system still around and not going away but a D implementation not very likely as it adds the other difficulty that it is not ASCII but EBCDIC. - AVR32 doesn't look very vivid. - Freescale Coldfire (as successor of 68K) also on a descending path - OpenRISC superseded by RISC-V Some CPU can do both but are generally used in little endian mode (ARM, Power) or also obsolete (Alpha, IA64). While from an intellectual perspective endiannes support is a good thing, from a pure pragmatic vue it is a solved issue. Little endian won, definitely (except on the network in the TCP/IP headers).
Re: How to delete dynamic array ?
On Wednesday, 17 March 2021 at 16:20:06 UTC, Steven Schveighoffer wrote: It's important to understand that [] is just a practical syntax for a fat pointer. Thinking of [] just as a fancy pointer helps imho to clarify that the pointed to memory nature is independant of the pointer itself.
Re: I learned something new in D this week! (anonymous class rundown)
On Thursday, 18 February 2021 at 04:31:39 UTC, Adam D. Ruppe wrote: Many of you know I've been around D for a long time now and picked up a lot of random tricks over the years, so it isn't every day I learn about a new old feature in the language's basic syntax. Would you like to know more? http://dpldocs.info/this-week-in-d/Blog.Posted_2021_02_15.html I also showed how you can use anonymous classes in betterC without any crazy hacks btw! Lately most my blog posts have just been quick updates on what features are coming in my libraries, but I still write these more general-knowledge kind of tips from time to time. (and sometimes the lib entries can be generally educational too like my little attempt at demystifying fibers a couple months ago: http://dpldocs.info/experimental-docs/arsd.fibersocket.html#conceptual-overview ) DWT users knew about anonymous classes as they are used a lot there. Of course as SWT is a Java based library, D had to had the features to ease the porting.
Re: Is returning void functions inside void functions a feature or an artifact?
On Monday, 2 August 2021 at 14:46:36 UTC, jfondren wrote: On Monday, 2 August 2021 at 14:31:45 UTC, Rekel wrote: [...] I don't know where you can find this in the docs, but what doesn't seem trivial about it? The type of the expression `print()` is void. That's the type that `doSomething` returns. That's the type of the expression that `doSomething` does return and the type of the expression following a `return` keyword in `doSomething`. Rather than a rule expressly permitting this, I would expect to find to either nothing (it's permitted because it makes sense) or a rule against it (it's expressly forbidden because it has to be to not work, because it makes sense). C, C++, Rust, and Zig are all fine with this. Nim doesn't like it. Wow. Just discovered that C accepts it. After 35 years of daily use of C, there are still things to discover.
Re: writef, compile-checked format, pointer
On Monday, 9 August 2021 at 19:38:28 UTC, novice2 wrote:
format!"fmt"() and writef!"fmt"() templates
with compile-time checked format string
not accept %X for pointers,
but format() and writef() accept it
https://run.dlang.io/is/aQ05Ux
```
void main() {
import std.stdio: writefln;
int x;
writefln("%X", ); //ok
writefln!"%s"(); //ok
//writefln!"%X"(); //compile error
}
```
is this intentional?
Yes. %X is to format integers. Runtime evaluation of a format
string does not allow for type checking. When using the template,
the evaluation can be thorough and the types can be checked
properly. You have 2 solutions for your problem, either a type
cast
writefln!"%X"(cast(size_t));
or using the generic format specifier that will deduce itself the
format to using depending in the passed type.
writefln!"%s"();
Re: GDC has just landed v2.098.0-beta.1 into GCC
On Friday, 3 December 2021 at 18:22:36 UTC, Iain Buclaw wrote: On Friday, 3 December 2021 at 13:48:48 UTC, Patrick Schluter wrote: On Tuesday, 30 November 2021 at 19:37:34 UTC, Iain Buclaw wrote: Hi, just a little question that annoys me in my project which is mainly written in C and clashes with the D code I'm integrating slowly into it. I generate the makefile dependencies with the -MMD option of gcc and that option generates .d files (which are not D language files), this is annoying as I had to rename my D files with a .D extension. Is there a way to force gcc to use another extension? Is this extension clash been solved somehow, as the man of gcc 10.2 lists .d as the extension for Dlang files. Yes, with -MF to specify the output dependency file. Thanks
Re: How to print unicode characters (no library)?
On Monday, 27 December 2021 at 07:12:24 UTC, rempas wrote: I don't understand that. Based on your calculations, the results should have been different. Also how are the numbers fixed? Like you said the amount of bytes of each encoding is not always standard for every character. Even if they were fixed this means 2-bytes for each UTF-16 character and 4-bytes for each UTF-32 character so still the numbers doesn't make sense to me. So still the number of the "length" property should have been the same for every encoding or at least for UTF-16 and UTF-32. So are the sizes of every character fixed or not? Your string is represented by 8 codepoints. The number of codeunits to represent them in memory depends on the encoding. D supports to work with 3 different encodings (in the Unicode standard there are more than these 3) string utf8s = "Hello \n"; wstring utf16s = "Hello \n"w; dstring utf32s = "Hello \n"d; Here the canonical Unicode representation of your string H e l l o \n U+0048 U+0065 U+006C U+006C U+006F U+0020 U+1F602 U+000a let's see how these 3 variable are represented in memory: utf8s : 48 65 6C 6C 6F 20 F0 9F 98 82 0a 11 char in memory using 11 bytes utf16s: 0048 0065 006C 006C 006F 0020 D83D DE02 000A 9 wchar in memory using 18 bytes utf16s: 0048 0065 006C 006C 006F 0020 0001F602 000A 8 dchar in memory using 32 bytes As you can see, the most compact form is generally UTF-8, that's why it is the preferred encoding for Unicode. UTF-16 is supported because of legacy support reason like it is used in the Windows API and also internally in Java. UTF-32 has one advantage, in that it has a 1 to 1 mapping between codepoint and array index. In practice it is not that much of an advantage as codepoints and characters are disjoint concepts. UTF-32 uses a lot of memory for practically no benefit (when you read in the forum about the big auto-decode error of D it is linked to this).
Re: Wrong result with enum
On Thursday, 11 November 2021 at 05:37:05 UTC, Salih Dincer wrote:
is this a issue, do you need to case?
```d
enum tLimit = 10_000; // (1) true result
enum wLimit = 100_000; // (2) wrong result
void main()
{
size_t subTest1 = tLimit;
assert(subTest1 == tLimit);/* no error */
size_t subTest2 = wLimit;
assert(subTest2 == wLimit);/* no error */
size_t gauss = (tLimit * (tLimit + 1)) / 2;
assert(gauss == 50_005_000); /* no error */
gauss = (wLimit * (wLimit + 1)) / 2;
assert(gauss == 5_000_050_000);/* failure
// Fleeting Solution:
enum size_t limit = 100_000;
gauss = (limit * (limit + 1)) / 2;
assert(gauss == 5_000_050_000); //* no error */
} /* Small Version:
void main(){
enum t = 10_000;
size_t a = t * t;
assert(a == 100_000_000);// No Error
enum w = 100_000;
size_t b = w * w;
assert(b == 10_000_000_000); // Assert Failure
}
*/
```
Integer overflow. By default an enum is defined as `int` which is
limited to 32 bit. `int.max` is 2_147_483_647 which is the
biggest number representable with an int.
You can declare the enum to be of a bigger type `enum : long { w
= 100_000 };`
or you can use `std.bigint` if you don't know the maximum you
work with or the library `std.experimental.checkedint` which
allows to set the behaviour one wants in case of overflow.
Re: Wrong result with enum
On Thursday, 11 November 2021 at 12:05:19 UTC, Tejas wrote:
On Thursday, 11 November 2021 at 09:11:37 UTC, Salih Dincer
wrote:
On Thursday, 11 November 2021 at 06:34:16 UTC, Stanislav
Blinov wrote:
On Thursday, 11 November 2021 at 05:37:05 UTC, Salih Dincer
wrote:
is this a issue, do you need to case?
```d
enum tLimit = 10_000; // (1) true result
enum wLimit = 100_000; // (2) wrong result
```
https://dlang.org/spec/enum.html#named_enums
Unless explicitly set, default type is int. 110 is
greater than int.max.
11
```d
enum w = 100_000;
size_t b = w * w;
// size_t b = 10 * 10; // ???
assert(b == 10_000_000_000); // Assert Failure
```
The w!(int) is not greater than the b!(size_t)...
Are you on 32-bit OS? I believe `size_t` is 32 bits on 32 bit
OS and 64 on a 64-bit OS
That's not the issue with his code. The 32 bit overflow happens
already during the `w * w` mulitplication. The wrong result is
then assigned to the `size_t`.
`cast(size_t)w * w` or the declaration `enum : size_t { w =
100_000 };` would change that.
Re: GDC has just landed v2.098.0-beta.1 into GCC
On Tuesday, 30 November 2021 at 19:37:34 UTC, Iain Buclaw wrote: Hi, just a little question that annoys me in my project which is mainly written in C and clashes with the D code I'm integrating slowly into it. I generate the makefile dependencies with the -MMD option of gcc and that option generates .d files (which are not D language files), this is annoying as I had to rename my D files with a .D extension. Is there a way to force gcc to use another extension? Is this extension clash been solved somehow, as the man of gcc 10.2 lists .d as the extension for Dlang files.
Re: issue with static foreach
On Thursday, 22 July 2021 at 03:43:44 UTC, someone wrote:
```
Now, if uncomment those two innocuous commented lines for the
if (true == true) block:
```d
labelSwitch: switch (lstrExchangeID) {
static foreach (sstrExchangeID; gstrExchangeIDs) {
mixin(r"case r"d, `"`, sstrExchangeID, `"`, r"d : "d);
mixin(r"classTickerCustom"d, sstrExchangeID, r"
lobjTicker"d, sstrExchangeID, r" = new classTickerCustom"d,
sstrExchangeID, r"(lstrSymbolID);"d);
mixin(r"if (true == true) {"d);
mixin(r"pobjTickersCustom"d, sstrExchangeID, r" ~=
lobjTicker"d, sstrExchangeID, r";"d);
mixin(r"pobjTickersCommon ~= cast(classTickerCommon)
lobjTicker"d, sstrExchangeID, r";"d);
mixin(r"}"d);
mixin(r"break labelSwitch;"d);
}
default :
break;
}
What an unreadable mess. Sorry.
I would have done something like that:
```d
mixin(format!
`case r"%1$s"d :
classTickerCustom%1$s lobjTicker%1$s = new
classTickerCustom%1$s (lstrSymbolID);
if (true == true) {
pobjTickersCustom%1$s ~= lobjTicker%1$s ;
pobjTickersCommon ~= cast(classTickerCommon)
lobjTicker%1$s ;
}
break labelSwitch;`(sstrExchangeID)
);
```
That's easier to edit imho.
Re: DMD now incorporates a disassembler
On Sunday, 9 January 2022 at 06:04:25 UTC, max haughton wrote: On Sunday, 9 January 2022 at 02:58:43 UTC, Walter Bright wrote: I've never seen one. What's the switch for gcc to do the same thing? For GCC/Clang you'd want -S (and then -masm=intel to make the output ~~beautiful to nobody but the blind~~ readable). I prefer -save-temps -fverbose-asm which generates a supplemental .i and .s file without changing the .o file.
Re: Make shared static this() encoding table compilable
On Monday, 14 March 2022 at 09:40:00 UTC, zhad3 wrote: Hey everyone, I am in need of some help. I have written this Windows CP949 encoding table https://github.com/zhad3/zencoding/blob/main/windows949/source/zencoding/windows949/table.d which is used to convert CP949 to UTF-16. After some research about how to initialize immutable associative arrays people suggested using `shared static this()`. So far this worked for me, but I recently discovered that DMD cannot compile this in release mode with optimizations. `dub build --build=release` or `dmd` with `-release -O` fails: ``` code windows949 function zencoding.windows949.fromWindows949!(immutable(ubyte)[]).fromWindows949 code table function zencoding.windows949.table._sharedStaticCtor_L29_C1 dmd failed with exit code -11. ``` I usually compile my projects using LDC where this works fine, but I don't want to force others to use LDC because of this one problem. Hence I'd like to ask on how to change the code so that it compiles on DMD in release mode (with optimizations). I thought about having a computational algorithm instead of an encoding table but sadly I could not find any references in that regard. Apparently encoding tables seem to be the standard. Why not use a simple static array (not an associative array). Where the values are indexed on `key - min(keys)`. Even with the holes in the keys (i.e. keys that do not have corresponding values) it will be smaller that the constructed associative array? The lookup is also faster.
Re: Make shared static this() encoding table compilable
On Thursday, 17 March 2022 at 11:36:40 UTC, Patrick Schluter
wrote:
On Monday, 14 March 2022 at 09:40:00 UTC, zhad3 wrote:
Hey everyone, I am in need of some help. I have written this
Windows CP949 encoding table
https://github.com/zhad3/zencoding/blob/main/windows949/source/zencoding/windows949/table.d which is used to convert CP949 to UTF-16.
After some research about how to initialize immutable
associative arrays people suggested using `shared static
this()`. So far this worked for me, but I recently discovered
that DMD cannot compile this in release mode with
optimizations.
`dub build --build=release` or `dmd` with `-release -O` fails:
```
code windows949
function
zencoding.windows949.fromWindows949!(immutable(ubyte)[]).fromWindows949
code table
function zencoding.windows949.table._sharedStaticCtor_L29_C1
dmd failed with exit code -11.
```
I usually compile my projects using LDC where this works fine,
but I don't want to force others to use LDC because of this
one problem.
Hence I'd like to ask on how to change the code so that it
compiles on DMD in release mode (with optimizations). I
thought about having a computational algorithm instead of an
encoding table but sadly I could not find any references in
that regard. Apparently encoding tables seem to be the
standard.
Why not use a simple static array (not an associative array).
Where the values are indexed on `key - min(keys)`. Even with
the holes in the keys (i.e. keys that do not have corresponding
values) it will be smaller that the constructed associative
array? The lookup is also faster.
Something akin to
```d
auto lookup(ushort key)
{
return cp949[key-0x8141];
}
immutable ushort[0xFDFE-0x8141+1] cp949 = [
0x8141-0x8141: 0xAC02,
0x8142-0x8141: 0xAC03,
0x8143-0x8141: 0xAC05,
0x8144-0x8141: 0xAC06,
0x8145-0x8141: 0xAC0B,
0x8146-0x8141: 0xAC0C,
0x8147-0x8141: 0xAC0D,
0x8148-0x8141: 0xAC0E,
0x8149-0x8141: 0xAC0F,
0x814A-0x8141: 0xAC18,
0x814B-0x8141: 0xAC1E,
0x814C-0x8141: 0xAC1F,
0x814D-0x8141: 0xAC21,
0x814E-0x8141: 0xAC22,
0x814F-0x8141: 0xAC23,
0x8150-0x8141: 0xAC25,
0x8151-0x8141: 0xAC26,
0x8152-0x8141: 0xAC27,
0x8153-0x8141: 0xAC28,
0x8154-0x8141: 0xAC29,
0x8155-0x8141: 0xAC2A,
0x8156-0x8141: 0xAC2B,
0x8157-0x8141: 0xAC2E,
0x8158-0x8141: 0xAC32,
0x8159-0x8141: 0xAC33,
0x815A-0x8141: 0xAC34,
0x8161-0x8141: 0xAC35,
0x8162-0x8141: 0xAC36,
0x8163-0x8141: 0xAC37,
...
0xFDFA-0x8141: 0x72A7,
0xFDFB-0x8141: 0x79A7,
0xFDFC-0x8141: 0x7A00,
0xFDFD-0x8141: 0x7FB2,
0xFDFE-0x8141: 0x8A70,
];
```
Re: Make shared static this() encoding table compilable
On Thursday, 17 March 2022 at 12:11:19 UTC, Patrick Schluter
wrote:
On Thursday, 17 March 2022 at 11:36:40 UTC, Patrick Schluter
wrote:
[...]
Something akin to
```d
auto lookup(ushort key)
{
return cp949[key-0x8141];
}
[...]
Takes 165 ms to compile with dmd 2.094.2 -O on [godbolt] with the
whole table generated from the Unicode link.
[godbolt]: https://godbolt.org/z/hEzP7rKnn]
Re: Make shared static this() encoding table compilable
On Thursday, 17 March 2022 at 12:19:36 UTC, Patrick Schluter
wrote:
On Thursday, 17 March 2022 at 12:11:19 UTC, Patrick Schluter
wrote:
On Thursday, 17 March 2022 at 11:36:40 UTC, Patrick Schluter
wrote:
[...]
Something akin to
```d
auto lookup(ushort key)
{
return cp949[key-0x8141];
}
[...]
Takes 165 ms to compile with dmd 2.094.2 -O on [godbolt] with
the whole table generated from the Unicode link.
[godbolt]: https://godbolt.org/z/hEzP7rKnn]
Upps, remove the ] at the end of the link to [godbolt]
[godbolt]: https://godbolt.org/z/hEzP7rKnn
Re: Teaching D at a Russian University
On Sunday, 20 February 2022 at 11:35:59 UTC, Mike Parker wrote: On Sunday, 20 February 2022 at 11:04:45 UTC, Patrick Schluter wrote: I read that the "for" as an equivalent of "because" was indeed almost extinct but was more or less resurrected by Tolkien as he used it throughout Lord of the Rings and the Hobbit.https://english.stackexchange.com/questions/566024/the-meaning-of-word-for-at-the-beginning-of-sentence Yes, the Tolkienesque way of using "for" at the beginning of a sentence is rarely used anymore. But it is still sometimes used in modern writing to join two independent clauses together in a single sentence, usually for flavor. The funny thing, as an English as third language learner (I grew up as French and German bilingual) Tolkienesque for never registered as something odd. It was only when a colleague, who happened to be a native english speaker, made a remark in one of my emails at work that I learnt about it.
Re: Teaching D at a Russian University
On Sunday, 20 February 2022 at 03:44:42 UTC, Paul Backus wrote: On Saturday, 19 February 2022 at 20:26:45 UTC, Elronnd wrote: On Saturday, 19 February 2022 at 17:33:07 UTC, matheus wrote: By the way English isn't my first language but I think there is a small typo: "In D, such nuances are fewer, for header files are not required." I think it's missing the word "example": "In D, such nuances are fewer, for example header files are not required." I think it is fine as is. Yes, this is a perfectly correct use of "for" as a coordinating conjunction. [1] It may come across as a bit formal or old-fashioned, though—in normal speech, you'd usually use "since". [1] https://writing.wisc.edu/handbook/grammarpunct/coordconj/ I read that the "for" as an equivalent of "because" was indeed almost extinct but was more or less resurrected by Tolkien as he used it throughout Lord of the Rings and the Hobbit.https://english.stackexchange.com/questions/566024/the-meaning-of-word-for-at-the-beginning-of-sentence
Re: ldc executable crashes with this code
On Thursday, 3 February 2022 at 02:01:34 UTC, forkit wrote: On Thursday, 3 February 2022 at 01:57:12 UTC, H. S. Teoh wrote: would be nice if the compiler told me something though :-( i.e. "hey, dude, you really wanna to that?" would be nice if programmers (C or D) learnt that a typecast means "shut up compiler I know what I do". You explicitly instructed the compiler to not complain. Remove the typecast and the compiler will bring an error. That's the reason why typecasts are to be avoided as much as possible.It is often a code smell.
Re: gdc or ldc for faster programs?
On Tuesday, 25 January 2022 at 22:41:35 UTC, Elronnd wrote: On Tuesday, 25 January 2022 at 22:33:37 UTC, H. S. Teoh wrote: interesting because idivl is known to be one of the slower instructions, but gdc nevertheless considered it not worthwhile to replace it, whereas ldc seems obsessed about avoid idivl at all costs. Interesting indeed. Two remarks: 1. Actual performance cost of div depends a lot on hardware. IIRC on my old intel laptop it's like 40-60 cycles; on my newer amd chip it's more like 20; on my mac it's ~10. GCC may be assuming newer hardware than llvm. Could be worth popping on a -march=native -mtune=native. Also could depend on how many ports can do divs; i.e. how many of them you can have running at a time. 2. LLVM is more aggressive wrt certain optimizations than gcc, by default. Though I don't know how relevant that is at -O3. -O3 often chooses longer code and unrollsmore agressively inducing higher miss rates in the instruction caches. -O2 can beat -O3 in some cases when code size is important.
Re: Programs in D are huge
On Thursday, 18 August 2022 at 17:15:12 UTC, rikki cattermole wrote: On 19/08/2022 4:56 AM, IGotD- wrote: BetterC means no arrays or strings library and usually in terminal tools you need to process text. Full D is wonderful for such task but betterC would be limited unless you want to write your own array and string functionality. Unicode support in Full D isn't complete. There is nothing in phobos to even change case correctly! Both are limited if you care about certain stuff like non-latin based languages like Turkic. A general toupper/tolower for Unicode is doomed to fail. As already mentioned Turkish has its specificity, but other languages also have traps. In Greek toupper/tolower are not reversible i.e. `x.toupper.tolower == x` is not guaranteed . Some languages have 1 codepoint input and 2 codepoints as result (German ß becomes SS in most cases, capital ẞ is not the right choice in most cases). etc. etc.
Re: Replacing tango.text.Ascii.isearch
On Thursday, 13 October 2022 at 08:27:17 UTC, bauss wrote:
On Wednesday, 5 October 2022 at 17:29:25 UTC, Steven
Schveighoffer wrote:
On 10/5/22 12:59 PM, torhu wrote:
I need a case-insensitive check to see if a string contains
another string for a "quick filter" feature. It should
preferrably be perceived as instant by the user, and needs to
check a few thousand strings in typical cases. Is a regex the
best option, or what would you suggest?
https://dlang.org/phobos/std_uni.html#asLowerCase
```d
bool isearch(S1, S2)(S1 haystack, S2 needle)
{
import std.uni;
import std.algorithm;
return haystack.asLowerCase.canFind(needle.asLowerCase);
}
```
untested.
-Steve
This doesn't actually work properly in all languages. It will
probably work in most, but it's not entirely correct.
Ex. Turkish will not work with it properly.
Greek will also be problematic. 2 different lowercase sigmas but
only 1 uppercase. Other languages that may make issues, German
where normally ß uppercases as SS (or not) but not the other way
round, but here we already arrived to Unicode land and the
normalization conundrum.
Re: Float rounding (in JSON)
On Thursday, 13 October 2022 at 19:27:22 UTC, Steven Schveighoffer wrote: On 10/13/22 3:00 PM, Sergey wrote: [...] It doesn't look really that far off. You can't expect floating point parsing to be exact, as floating point does not perfectly represent decimal numbers, especially when you get down to the least significant bits. [...] To me it looks like there is a conversion to `real` (80 bit floats) somewhere in the D code and that the other languages stay in `double` mode everywhere. Maybe forcing `double` by disabling x87 on the D side would yield the same results as the other languages?
Re: A look inside "filter" function defintion
On Tuesday, 2 August 2022 at 12:39:41 UTC, pascal111 wrote: On Tuesday, 2 August 2022 at 04:06:30 UTC, frame wrote: On Monday, 1 August 2022 at 23:35:13 UTC, pascal111 wrote: This is the definition of "filter" function, and I think it called itself within its definition. I'm guessing how it works? It's a template that defines the function called "Eponymous Templates": https://dlang.org/spec/template.html#implicit_template_properties A template generates code, it cannot be called, only instantiated. The common syntax is just a shortcut for using it. Otherwise you would need to write `filter!(a => a > 0).filter([1, -1, 2, 0, -3])`. Like UFCS, some magic the compiler does for you. Instantiation seems some complicated to me. I read "If a template contains members whose name is the same as the template identifier then these members are assumed to be referred to in a template instantiation:" in the provided link, but I'm still stuck. Do you have a down-to-earth example for beginners to understand this concept? A template is conceptually like a macro with parameters in C. An instantiation is like the using of the macro in your C program. The fundamental difference is, that the template is syntactically and semantically linked to the language. In C, the preprocessor was just a textual replacement done before the proper compilation. This meant that there are things that you couldn't do in the pre-processor (like `#if sizeof(int)==4`) and (horrible) things that never should have been possible (I used to use the C pre-processor with other languages like AutoLISP and dBase III).
Re: Safer Linux Kernel Modules Using the D Programming Language
On Monday, 9 January 2023 at 09:08:59 UTC, areYouSureAboutThat wrote: On Monday, 9 January 2023 at 03:54:32 UTC, Walter Bright wrote: Yes, as long as you don't make any mistakes. A table saw won't cut your fingers off if you never make a mistake, too. And yet, people keep using them (table saws). Don't underestimate the level of risk humans are happily willing to accept, in exchange for some personal benefit. and people literally kill themselves by overestimating their skills https://youtu.be/wzosDKcXQ0I?t=441
Re: Idiomatic D using GC as a library writer
On Sunday, 4 December 2022 at 23:37:39 UTC, Ali Çehreli wrote: On 12/4/22 15:25, Adam D Ruppe wrote: > which would trigger the write barrier. The thread isn't > allowed to complete this operation until the GC is done. According to my limited understanding of write barriers, the thread moving to 800 could continue because order of memory operations may have been satisfied. What I don't see is, what would the GC thread be waiting for about the write to 800? I'm not a specialist but I have the impression that GC write barrier and CPU memory ordering write barriers are 2 different things that confusedly use the same term for 2 completely different concepts. Would the GC be leaving behind writes to every page it scans, which have barriers around so that the other thread can't continue? But then the GC's write would finish and the other thread's write would finish. Ok, here is the question: Is there a very long standing partial write that the GC can perform like: "I write to 0x42, but I will finish it 2 seconds later. So, all other writes should wait?" > The GC finishes its work and releases the barriers. So, it really is explicit acquisition and releasing of these barriers... I think this is provided by the CPU, not the OS. How many explicit write barriers are there? Ali
