Re: Phobos: __FILE__ as template default parameter

[Lass Safin via Digitalmars-d]

On Saturday, 18 June 2016 at 18:13:22 UTC, Johan Engelen wrote:
An example of how __FILE__ as template parameter will break 
your library:


In library, distributed in binary+source form:
```
alias file_templ_alias = file_templ!bool;
T file_templ(T, string file = __FILE__, size_t line = __LINE__) 
(T value) {

return value;
}
```
In user code, linking to the library binary:
```
bool foo(bool b){
return file_templ_alias(b);
}
```
By calling the alias, both DMD and LDC will decide that the 
template does not need reinstantiation in the user object file 
and will try to link with the symbol in the library binary. So 
you have to be lucky to install the library source in the same 
path as where it was when the library was built on someone 
else's machine, otherwise you'll get a linker error and are 
left wondering what went wrong.


-Johan


Can't one just use __MODULE__ instead?

So:
T file_templ(T, string mod = __MODULE__, size_t line = __LINE__)
(T value) {
return value;
}

Re: D plugin for Visual Studio Code

[Lass Safin via Digitalmars-d]

On Sunday, 22 May 2016 at 12:16:36 UTC, Martin Nowak wrote:
Anyone working on a D language plugin for Visual Studio's cross 
platform IDE?
Of course we're late to the party, language support for 
everything else is already there.

http://code.visualstudio.com/

How is the D language experience on Atom and Sublime Text?


There are about 3 plug-ins for D on Atom, all of which aren't 
exactly spectacular.
They are all missing a few keywords IIRC and/or also fuck up your 
syntax highlighting quite badly with some constructions 
(primarily the ones with parentheses).

Re: My favourite game: DMD guess the error reason.

[Lass Safin via Digitalmars-d]

On Monday, 2 May 2016 at 07:13:17 UTC, Iain Buclaw wrote:
Here's a small puzzle, in which there are both a simple and 
cryptic combined. To make it easier, I've added a some multiple 
choice answers at the bottom.

[...]
std/uni.d:2627:50: error: template 
std.algorithm.searching.countUntil cannot deduce function from 
argument types !("a[0] > 0x80")(CodepointInterval[]), 
candidates are:

[...]
[1]: Template deduction/matching failed to find a suitable 
candidate for countUntil.

[...]


1

Re: Using private constructor with std.experimental.allocater:make

[Lass Safin via Digitalmars-d-learn]

On Sunday, 1 May 2016 at 11:17:27 UTC, earthfront wrote:

Hello!
[...]
 class A
   { int b; private this(int a){b=a;} }
[...]


I don't think classes are supposed to be able to have a private 
constructor...

Re: aquivalent to pragma comment

[Lass Safin via Digitalmars-d]

On Thursday, 28 April 2016 at 16:05:39 UTC, andi wrote:

hey guys,

as the title says, im looking for an aquivalent to pragma 
comment(linker, "export:functionname"), is there any in D?


greetings,
   Andi


export void functionname() {}

There.

Re: Checking if an Integer is an Exact Binary Power

[Lass Safin via Digitalmars-d]

On Saturday, 23 April 2016 at 21:04:52 UTC, Nordlöw wrote:

On Saturday, 23 April 2016 at 20:42:25 UTC, Lass Safin wrote:

CPUID: https://en.wikipedia.org/wiki/CPUID.
You can check for the presence of a lot of instructions with 
this instruction.

However this will only work on x86 and only run-time.


Code you give a complete code example in D, please or point out 
a suitable place in druntime/phobos?


I just found this: 
https://dlang.org/phobos/core_cpuid.html#.hasPopcnt! It does 
exactly as it says: checks if the system has popcnt.
Though read the top of https://dlang.org/phobos/core_cpuid.html 
before you use it:

Bugs:
Currently only works on x86 and Itanium CPUs. Many processors 
have bugs in their
microcode for the CPUID instruction, so sometimes the cache 
information may be

incorrect.


Example;

import core.bitop;
import core.cpuid;

int count;
if(hasPopcnt)
count = _popcnt; // Uses x86-instruction "popcnt".
else
count = popcnt; // Phobos's software implementation.

// Do stuff with count

Will the GC scan this pointer?

[Lass Safin via Digitalmars-d-learn]

// Omitting the required imports.

void[] ptr;

void main() {
uint buffer;
glCreateBuffers(1, );
// Filling the buffer with data and such...
ptr = glMapNamedBufferRange(buffer, 0, 512, GL_MAP_WRITE_BIT 
| GL_MAP_PERSISTENT_BIT | GL_MAP_COHERENT)[0 .. 512];

}

So the question is: Will the GC scan ptr? As you can see, it is a 
write-only pointer, so reading from it will cause undefined 
behavior (such as return data which looks like a pointer to 
data..), and can potentially be reallly slow.


Do I have to mark it with NO_SCAN each time I call 
glMapNamedBufferRange?

Re: Checking if an Integer is an Exact Binary Power

[Lass Safin via Digitalmars-d]

On Saturday, 23 April 2016 at 20:34:52 UTC, Nordlöw wrote:
On Saturday, 23 April 2016 at 17:28:21 UTC, Andrei Alexandrescu 
wrote:
Yah, that's the canonical. I forgot why I chose (x & -x) > (x 
- 1) over

it. -- Andrei


So is there a way to check if popcnt builtin is available on 
current platform?


CPUID: https://en.wikipedia.org/wiki/CPUID.
You can check for the presence of a lot of instructions with this 
instruction.

However this will only work on x86 and only run-time.

Re: Why does map take lambda as a template parameter

[Lass Safin via Digitalmars-d-learn]

On Saturday, 23 April 2016 at 20:06:39 UTC, xtreak wrote:
map takes lambda as a template parameter and so does filter and 
many other functions. Sometimes they take something other than 
lambda as a template parameter. Eg. In case of to!int("5") int 
is a type and hence might need it as a template parameter but 
why does map and others take it as template parameter.


Adam D Ruppe pointed out in IRC it helps in inlining and 
optimization. Is there a thumb rule to decide this so that my 
functions too can benefit the performance and hence I could 
structure and understand my code better.


Non-template function parameters can not be inlined, since 
they're not determinable at compile-time, only at run-time.
You can have two versions if you want, one with the function as a 
template parameter, and one with it as a function pointer.


I don't really think there is a rule of thumb to it other than 
using templates when you desire performance and also nicer syntax 
(in my opinion).


Templates also use up more space in the executable by the way, so 
if you're developing on a platform with very limited memory, then 
function pointers may be the better alternative.

Re: VariantPointer

[Lass Safin via Digitalmars-d-learn]

On Wednesday, 20 April 2016 at 20:07:31 UTC, Nordlöw wrote:

On Wednesday, 20 April 2016 at 16:08:32 UTC, Lass Safin wrote:
core.memory.GC.setAttr can set attributes for a block of 
memory, with which you can set the attribute NO_SCAN, which as 
it implies, forces that no scan be done in the particular 
block of memory.
This can be used to insure that the GC doesn't mark blocks not 
alive as alive.


Is this needed

- *only* for regions allocated with GC.malloc or
- *also* for memory allocated with non malloc/calloc/realloc?


NO_SCAN should probably be set for all types of memory blocks. I 
don't even know if the GC actually scans mallocated memory in the 
first place.

Re: about destroy and delete.

[Lass Safin via Digitalmars-d]

On Wednesday, 20 April 2016 at 08:10:15 UTC, Dsby wrote:

I see https://dlang.org/deprecate.html#delete
The delete will be removeed,  when will be deprecate?

and i test destroy/GC.free and delte in struct, the value is 
difference;


struct Struct
{
string value = "struct";
~this()
{
writeln(value);
}
}

void main()
{

auto s = new Struct();
delete s;

writeln("");

}

will printf :
struct


But in
void main()
{

auto s = new Struct();
s.destroy;
GC.free(s);

writeln("");

}

will printf :

struct

If I only GC.free(s); only printf: 

so, I want to know why don't destroy direct printf ?


This is according to the reference, however this behavior should 
probably be changed to match that of the class, which will call 
the destructor immediately.

Re: VariantPointer

[Lass Safin via Digitalmars-d-learn]

On Wednesday, 20 April 2016 at 14:36:54 UTC, Nordlöw wrote:

On Wednesday, 20 April 2016 at 13:41:27 UTC, Nordlöw wrote:

At

https://github.com/nordlow/phobos-next/blob/master/src/variant_pointer.d


Further:

What to do with fact that the GC will fail to scan 
VariantPointers?


Can the GC be tweaked to mask out the type bits before scanning?


core.memory.GC.setAttr can set attributes for a block of memory, 
with which you can set the attribute NO_SCAN, which as it 
implies, forces that no scan be done in the particular block of 
memory.
This can be used to insure that the GC doesn't mark blocks not 
alive as alive.
Then, use GC.addRoot with the pointer to your actual data, with 
the typeinfo bits cleared, passed as a parameter, to add an 
internal pointer inside the GC itself to the data, so that is 
considered live until removeRoot is called on the same pointer. 
addRoot and removeRoot can be put into this and ~this, 
respectively.

Re: VariantPointer

[Lass Safin via Digitalmars-d-learn]

On Wednesday, 20 April 2016 at 13:41:27 UTC, Nordlöw wrote:

At

https://github.com/nordlow/phobos-next/blob/master/src/variant_pointer.d

I've implemented a pointer-only version of Variant called 
VariantPointer.


[...]

It safe to assume that `typeBits` most significant bits of a 
pointer on a 64-bit system are always zero?


Note that I didn't want to use the lower bits because I'm 
currently unsure whether I need to represent stack-pointers 
aswell.


I'm very sure that there is no obligation for the OS to not issue 
a stack of memory starting at addresses near the limit of a 
64-bit system. Thus, you can't count on it 100% of the time, 
though it is so rare as far as I know, that a simple enforce() 
for checking that the upper bits are clear should be acceptable. 
Though, it may perhaps be unusable in a few decades time, if you 
still care then.


I can't answer your second question.

Re: So what does (inout int = 0) do?

[Lass Safin via Digitalmars-d]

On Saturday, 16 April 2016 at 22:06:10 UTC, Marco Leise wrote:

Am Fri, 15 Apr 2016 09:44:05 -0400
schrieb Andrei Alexandrescu :

inout must go. -- Andrei

Ceterum censeo Carthaginem esse delendam. -- Marcus Porcius Cato
:o)


What does that have to do with what he said?
Are you comparing him to Cato?

Re: Cancelling a stdin.read?

[Lass Safin via Digitalmars-d-learn]

On Monday, 11 April 2016 at 14:53:31 UTC, Adam D. Ruppe wrote:

On Sunday, 10 April 2016 at 08:29:22 UTC, Lass Safin wrote:
Thus, my question is: Is there any way to cancel the read from 
stdin prematurely from another thread, so that the thread can 
finish?


What operating system are you on?

I wouldn't be using threads for this at all, you might want to 
reorganize the program to get terminal events sent to the same 
gui event loop so exiting it would exit all of it.


But failing that, canceling an I/O request can be done by 
sending yourself a signal on posix and on Windows there's a 
system API call that one thread can cancel another thread's 
blocking read.


The D library would see these cancels as an error and throw an 
exception. You could catch it or let it kill the thread, since 
you want to exit anyway.


My savior!
I can't put it in one loop, since the window also has some 
autonomous features.

Re: Cancelling a stdin.read?

[Lass Safin via Digitalmars-d-learn]

On Sunday, 10 April 2016 at 18:00:31 UTC, hilop wrote:

On Sunday, 10 April 2016 at 08:29:22 UTC, Lass Safin wrote:


I have a multi-threaded program, one thread drawing to a 
window and handling it, the other handling stdin.


[...]


The external program that writes to the input has to close it 
when it has finished to write.


I'm writing from my terminal, and I have my graphical window 
opened beside it.
I want to close the input from not an external program, but 
rather from within.

Cancelling a stdin.read?

[Lass Safin via Digitalmars-d-learn]

I have a multi-threaded program, one thread drawing to a window 
and handling it, the other handling stdin.


The thread which handles stdin is something like this:
char[] buf;
while(true) {
readln(buf);
}

The window thread also has to receive close-events from the OS, 
such as when the user pressed Ctrl-Q or whatnot.

The following code is what I used to terminate my program:
import core.runtime : Runtime;
import core.stdc.stdlib : exit;
Runtime.terminate;
exit(0);

However this doesn't work, because Runtime.terminate waits for 
the other threads to terminate before proceeding.


So I thought about replacing my above loop with somethings like 
this:

while(NOTCLOSING) {
...
}

But this doesn't work either, because the conditional clause 
first gets read when a single loop finishes.

And my loop won't finish until I give it input via stdin.
This means that I can't use e.g. the close button for closing the 
button, without also writing to stdin.


Because of this, I have to resort to an exit(0) alone, forcing 
the program to terminate without running destructors (static 
destructors are my concern here..) of any kind.


Thus, my question is: Is there any way to cancel the read from 
stdin prematurely from another thread, so that the thread can 
finish?


Or perhaps, just running the shared static destructors alone, so 
that at least they can get run before closing via exit?

Re: The Sparrow language

[Lass Safin via Digitalmars-d]

On Wednesday, 6 April 2016 at 16:56:17 UTC, Kagamin wrote:
On Wednesday, 6 April 2016 at 13:15:48 UTC, Andrei Alexandrescu 
wrote:
Anyway it's a new level of type system. Does D still accept new 
features of such complexity?


D3?

Re: We gunna be rich

[Lass Safin via Digitalmars-d]

On Saturday, 2 April 2016 at 21:03:28 UTC, Patience wrote:
On Saturday, 2 April 2016 at 15:43:53 UTC, Andrei Alexandrescu 
wrote:
Hello all, I've created an Amazon Affiliates link for the D 
Language Foundation (dlang-20). Subsequently I've changed 
https://wiki.dlang.org/Books to use it. Please follow up with 
changing dlang.org to also use the links, and also let me know 
if you need affiliate links for any other products. Thanks! -- 
Andrei


Wait, how is this going to make me be rich? I think you left 
that part out?


1. More money for Developers (pun heavily intended)
2. More incentive to work
3. Better language
4. More people know about it
5. You're now a computer wizard and everyone's trying to hire you
6. Profit

Re: How my little brother try D

[Lass Safin via Digitalmars-d]

On Saturday, 2 April 2016 at 21:29:27 UTC, Daniel Kozak wrote:
Few days ago, my little brother (13 years old) ask me about 
writing some small utility. He needed find all files with 
selected extensions and move them to some another location. He 
asked me about using D or C# for it. My answer was: try both 
and you will see which one suited you better.

[...]
Maybe it would be nice to have alias for rename method or have 
better doc for rename. And probably we should fixed copy method 
to not remove files with same src and dst path :)


You're right in how it isn't obvious for non-techy people. I do 
suppose it would be doable without breaking any old code (unless 
for some arcane reason the code depends on static 
assert(!__traits(allMember, std.file).canFind("move"))...), so 
why not create a PR with "alias move = rename" inside?

Re: Any reason as to why this isn't allowed?

[Lass Safin via Digitalmars-d]

On Saturday, 2 April 2016 at 16:58:14 UTC, Paul O'Neil wrote:

On 04/02/2016 09:02 AM, Lass Safin wrote:

class C {
 ~this() {}
 immutable ~this() {}
}

This gives a conflict error between the two destructors.


What do you expect the difference to be?  I'm not sure what I 
expect the semantics of destroying an immutable object to be.


It's more that I wish the immutable destructor to be empty, thus 
never destroying it properly.


I just don't really see the reason as to why we can have 
immutable and mutable constructors but not immutable and mutable 
destructors.


Though currently it is possible if I create two functions, one 
immutable and one not, then set the value inside the vtable 
manually within two constructors, again, one immutable and one 
not.

Any reason as to why this isn't allowed?

[Lass Safin via Digitalmars-d]

class C {
~this() {}
immutable ~this() {}
}

This gives a conflict error between the two destructors.

Re: Oh, my GoD! Goroutines on D

[Lass Safin via Digitalmars-d]

On Monday, 28 March 2016 at 13:10:45 UTC, Jin wrote:

On Sunday, 27 March 2016 at 20:39:57 UTC, Walter Bright wrote:

On 3/27/2016 11:17 AM, Jin wrote:

[...]


Nice! Please write an article about this!


My english is too bad to write articles, sorry :-(


Just use engrish, we won't care. Really.

Re: Females in the community.

[Lass Safin via Digitalmars-d]

On Thursday, 17 March 2016 at 20:03:08 UTC, John Carter wrote:
It is very clear from the 'net that some communities welcome 
woman, and some actively hate them, some ignore them.


I personally would feel reluctant to get involved in anything 
where there was a high probability of vitriolic rejection. 
(Yes, sadly, some 'net communities have, unfortunately, gone to 
very extreme lengths in their rejection.)


Part me says ignore them, gender has nothing to do with 
programming.


Part of me observes we are human first, programmers second, and 
human groups with a healthy gender mix are simpler more 
pleasant and functional places.


Certainly Python has done well to actively welcome them, and I 
would suggest we do the same.


So a simple statement of welcome and some level of outreach 
would go a long way.


https://www.gnome.org/outreachy/


Currently, internships are open >internationally to women (cis 
and trans), >trans men, and genderqueer people. >Additionally, 
they are open to residents >and nationals of the United States 
of any >gender who are Black/African American, >Hispanic/Latin@, 
American Indian, Alaska >Native, Native Hawaiian, or Pacific 
Islander. We are planning to expand the >program to more 

participants from >underrepresented backgrounds in the >future.


I, I mean, I just really CAN'T take you seriously, when you link 
shit like that.


I mean, sure, groups with a better balance of women and men tend 
to fare better, but thing is, we don't really care about the 
gender of someone, whom we aren't with physically. We just don't. 
The only moment, where members of the D community meet each 
other, is at DConf, and we aren't holding DConf every single day 
of the year.


And the thing which you've linked to, that (absolutely 
horrendous) outreachy thing, is something I'd rather actually not 
see, if I was a women: I wouldn't fucking want to join a 
community, who presents a text like that to my face. What the 
_fuck_ is shit like "cis" and "genderqueer" supposed to mean? 
When I see a text like that, all I think is that the community 
surrounding this language (or software or I don't know whhat) is 
instead of focusing on improving the language, focusing om fixing 
social pseudo-problems. This is a huge turn-off for me.


Just, please, don't.

Re: How do I extend an enum?

[Lass Safin via Digitalmars-d-learn]

On Saturday, 19 March 2016 at 17:40:27 UTC, Lass Safin wrote:

Why:

enum Base {
A,
B,
}

enum Derived : Base {
C, // Gives error, says it can't implicitly convert 
expression to Base.

D = 1, // Same error
E = cast(Base)294, // Finally works. Can only be 
cast(Derived) instead.

}

void func(Derived d) {}

func(Derived.E); // works.
func(Derived.A); // Gives error, says it can't call function 
with Base.A.

func(cast(Derived)Derived.A); // Works.

So, what's the proper way of extending an enum?


Meant "Can also be cast(Derived) instead."

How do I extend an enum?

[Lass Safin via Digitalmars-d-learn]

Why:

enum Base {
A,
B,
}

enum Derived : Base {
C, // Gives error, says it can't implicitly convert 
expression to Base.

D = 1, // Same error
E = cast(Base)294, // Finally works. Can only be 
cast(Derived) instead.

}

void func(Derived d) {}

func(Derived.E); // works.
func(Derived.A); // Gives error, says it can't call function with 
Base.A.

func(cast(Derived)Derived.A); // Works.

So, what's the proper way of extending an enum?

Re: Is D a good choice for embedding python/octave/julia

[Lass Safin via Digitalmars-d-learn]

On Sunday, 13 March 2016 at 13:02:16 UTC, Bastien wrote:

Hi, apologies for what may be a fairly obvious question to some.

## The background:
I have been tasked with building software to process data 
output by scientific instruments for non-experts - basically 
with GUI, menus, easy config files (JSON or similar) - and the 
ability to do some serious number crunching.


My background is python/octave and would be happy building it 
in python (or god forbid, even octave), but it would end up 
clunky and slow once ported to a standalone executable. Hence 
why I'm looking at other languages. D caught my eye.


## The problem:
The sticking point is unless I commit the rest of my life to 
maintaining this software, I can't write it all in D. The 
algorithms change/are improved yearly; the output format from 
the instrument changes once in a while and therefore these need 
to be easily scripted/modified by other (non-programming) 
scientists and the community that only really know python and 
octave.


Essentially I'd like a D front end, and a D back-end that does 
most of the memory and data management but calls and interprets 
.py, .m and/or .jl scripts (python, matlab, julia) to know how 
to treat the data. This leaves the py/m/jl scripts visible to 
be edited by the end user.


## The question:
Can it be done?
Does this entirely defeat the point of using D and I should 
just code it in python because of the added overheads?



Thanks for your help!
B


I REALLY don't think you should use _any_ scripted language, if 
what you're looking for is speed.

Now for your main question:
It can be done.
An incomplete list of libraries and bindings for D: 
http://wiki.dlang.org/List_of_Libraries_and_Frameworks.

It includes tools such as GTK.

And I'm very sure that it will be faster than writing it 
completely in python.


Another thing: I myself find D *much* easier to program in than 
python (having experience in both). The many meta-programming 
tools in D and the nice syntactic features of D really make-up 
for the increased complexity of the language compared to Python.



Somethings I'd like to recommend: OpenCL. For algorithms and 
such, using the GPU is much much faster than using the CPU.

Re: Parameterized Keywords

[Lass Safin via Digitalmars-d]

On Monday, 7 March 2016 at 05:56:54 UTC, Patience wrote:

int[size] <- creates an integer of size bits.


You declare arrays of integers with int[size], you know that, 
right?


And I really don't see any useful improvement, that could be 
added with this. It would just be wasted efforts.

Re: Uniform Function Call Syntax?

[Lass Safin via Digitalmars-d]

On Monday, 7 March 2016 at 07:58:53 UTC, Era Scarecrow wrote:
On Monday, 7 March 2016 at 06:57:48 UTC, Ola Fosheim Grøstad 
wrote:

immutable π = 3.14;

Oh, the horror!


 With the assumption pi is declared elsewhere (say, in 
std.math), what i wonder is the number for pi vs 2 letters. 
Unicode 03C0h, so now i have to convert that to decimal, code 
960. Alt+960 = └


 That's not pi... Looking up the symbol by itself in the 
character map was annoying enough. No, this is not a good idea 
unless it's easily accessible, preferably with 2 or fewer 
keystrokes to symbolize pi.



 As a reminder most of us are programmers, not scientists or 
mathematicians. Having specialized symbols won't give us any 
benefit. It's not like we're filling out a complex formula with 
college level math for a thesis.


Have you ever heard of .XCompose?
For linux: https://github.com/kragen/xcompose
For windows: https://github.com/samhocevar/wincompose
How it works:
You choose a compose key, then use it to compose special 
characters with specific sequences.


Examples:
ComposeKey, *, p: π.
ComposeKey, s, s: ß
ComposeKey, ComposeKey, d, e, g, c (degree Celsius): ℃

It is not impossible to use unicode special characters on a daily 
base easily, with the use of this tool. No need to use the 
character map or anything.
I think it would be very nice, if one had the option of using 
these special characters.
E.g. → instead of >>, if you desire that; std.math defining π as 
π.
Small gimmicks like these are things I find to be good for a 
language to have.

Re: GSoC 2016 "GDC Project - The GNU D Compiler" project

[Lass Safin via Digitalmars-d]

On Tuesday, 1 March 2016 at 11:50:02 UTC, Abhishek Kumar wrote:

Hello
I am Abhishek Kumar,computer science student from India.I am 
interested in working on D language during GSoC 2016.I found 
"GDC Project - The GNU D Compiler" interesting.
I have interest in programming languages and compilers.I have 
been working on a Python to C++ code converter,also I am 
writing a Javascript parser for code minification in 
Scala(Using scala fastparse). I have prior open source 
experience in Scala and good knowledge of C/C++.

  Can someone help me with how to start and get familiar with D?
I'll be glad to have your help and suggestions.

Thanks
Abhishek Kumar


I had good C/C++ experience before learning D, thus to learn D I 
simply read the entire language reference at 
http://dlang.org/spec/intro.html; though you may find it a bit 
boring.