Re: Compiler version "dirty"

2021-05-22 Thread Norm via Digitalmars-d-learn

On Monday, 8 March 2021 at 22:29:58 UTC, Q. Schroll wrote:

When I enter `dmd --version`, it says:
  DMD64 D Compiler v2.095.1-dirty
What should the "dirty" mean? To me, it seems looks something 
went wrong somewhere.


This comes from `git describe --dirty` and indicates there were 
uncommitted changes in the repo when the release was built. This 
would raise red flags if seen in a commercial setting and looks a 
bit unprofessional but it is most likely harmless. Probably one 
of the build scripts or unittests are polluting the repo.






Re: why is "hello".writeln considered bad?

2020-11-20 Thread norm via Digitalmars-d-learn

On Friday, 20 November 2020 at 18:46:40 UTC, Martin wrote:

On Friday, 20 November 2020 at 10:03:18 UTC, Daniel Kozak wrote:
I remember days when I liked UFCS too . Unfortunately  it is 
not so awesome when you use it with IDE.


And I would like to add: if you use in a bigger team. It's 
annoying when every dev have a own taste.. And together with 
optional () it's hell - no joke.
The need to think about codeatyle definitions in such detail is 
a nogo for big projects.


This is a good point. I find with D there are many different ways 
to write code and each can look different on the page. Where I 
work we mandated all D code will be implemented in Phobos style 
and use Phobos and mir source as guides. Some parts do heavily 
use UFCS/optional() and some parts do not. We have not had issues 
with readability, but maybe our D code isn't that complicated 
because it is mostly PC side data analysis tools.


Personally a really like UFCS, even `"hello".writeln;` and I 
think I'd rather have UFCS than autocompletion. But then I did 
start out in industry well before autocomplete was a thing so 
maybe I have never relied on it too much.



Thanks all for the replies!
norm




why is "hello".writeln considered bad?

2020-11-19 Thread norm via Digitalmars-d-learn
I was reading some posts and this was presented as a snippet of 
code and was immediately flagged as bad practice.


I get some people don't like it but occasionally I prefer this 
syntax. It feels more declarative and fluent in style. Is there a 
good technical reason why it is bad practice, e.g. does it make 
it easier to write bugs? Or is it just what people are used to?


Thanks,
norm


Re: sort a string

2020-05-01 Thread norm via Digitalmars-d-learn

On Friday, 1 May 2020 at 07:38:53 UTC, Chris Katko wrote:
I'm making anagrams. According to the nextPermutation() docs, I 
need to 'sort by less' to get all permutations. ... Except the 
doc page doesn't mention how to do that, nor does 
std.algorithm.sort show how to sort a string. ... and the 
google results on the dlang forums from 2017 don't work.


I've tried .byCodeUnit. , .representation. I've tried sorting 
on the dchar. I've tried sorting the on string.


The closest I've gotten:

string word = "bar";
string line2 = toLower!(string)(word);
dchar[] line3 = sort(line2.to!(dchar[]));

"Error: cannot implicitly convert expression sort(to(line2)) of 
type SortedRange!(dchar[], "a < b") to dchar[]"


You need to convert the sort output to dchar[], e.g.
---
dchar[] line3 = sort(line2.to!(dchar[])).to!(dchar[]);
---

Cheers,
Norm



Re: How to call a extern C++ class constructor ?

2020-02-01 Thread norm via Digitalmars-d-learn

On Saturday, 1 February 2020 at 08:38:22 UTC, Luhrel wrote:
On Saturday, 1 February 2020 at 08:32:51 UTC, Ferhat Kurtulmuş 
wrote:

On Saturday, 1 February 2020 at 08:27:07 UTC, Luhrel wrote:
On Saturday, 1 February 2020 at 08:21:29 UTC, Ferhat 
Kurtulmuş wrote:


You cannot. 
https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d


You must use a factory method like createInstance.


Oh I see, so there's definitively no way to call a c++ ctor 
without modifying the c++ code ?


İf you are not allowed to modify that c++ code, you can write 
a createInstance function in your custom cpp file.


That was my fear.


It isn't too bad, you need a simple wedge written in C++ that 
returns an instance of any T you want. A simple template function 
usually works, or to make it more generic you can use a variadic 
template to handle N args, but I find variadic templates in C++ 
are still annoying to use.


Re: Indexed graphics for retro engine?

2019-09-19 Thread norm via Digitalmars-d-learn
On Thursday, 19 September 2019 at 20:47:45 UTC, Shadowblitz16 
wrote:
On Thursday, 19 September 2019 at 19:16:03 UTC, Mike Parker 
wrote:
On Thursday, 19 September 2019 at 18:25:05 UTC, Shadowblitz16 
wrote:



I wanted to do 4bpp 16 color graphics.
and I didn't want to load anything unnecessary in the image 
like the palette but instead supply it myself as a Color[16];


I see. In that case, I suggest you find some tutorials on 
software rendering in C or C++ and adapt them to D. Most of 
the modern stuff out there is going to be targeting 24-bit or 
32-bit graphics. You might find some older tutorials on 
indexed 8-bit rendering that you can adapt to 4-bit. Nothing 
to it but storing the palette indices in a byte array.


can I do this in D and draw them to a 32bpp bitmap pixel by 
pixel?

I would prefer do do this on the gpu but I don't know how.


I'd create a fragment shader to convert each pixel to 8 bit. 
There are many examples on the web about creating fragment 
shaders and 2d opengl scenes, i.e. a 2d scene where OpenGL 
coordinates are integer pixel coordinates. Once you get that you 
then just implement the conversion routine.


Using the shader you can render the image as a textured quad and 
send the colour look up table down as an additional 1d texture. 
This way you can have several D arrays for each colour table and 
simply swap the texture buffer pointer to instantly switch 
colours.


You can also get cool effects this way when you move to 3d using 
8 bit colour tables.




Re: static if (is (T==Complex))

2019-09-18 Thread Norm via Digitalmars-d-learn

On Wednesday, 18 September 2019 at 11:10:11 UTC, berni wrote:

Is it possible to simplfy this?

static if (is (T==Complex!double) || is (T==Complex!float) || 
is (T==Complex!real))


I usually do something like the following:
---
import std.traits;


template isComplexReal(T) {

  enum isComplexReal = is(T == Complex!R, R) && 
(isFloatingPoint!R);

}


static if(isComplexReal!T) {// do something}
---


Re: Make executable archive just like Java's .jar archive?

2019-09-12 Thread norm via Digitalmars-d-learn

On Thursday, 12 September 2019 at 12:52:48 UTC, BoQsc wrote:
Is there a way to archive multiple .d source code files and 
make that archive executable, or something similar?


You can achieve something similar with rdmd and shell;

$ tar -zcvf source_files.tar.gz source1.d source2.d ... sourceN.d

$ rdmd $(tar -xvf source_files.tar.gz)


I imagine it wouldn't take much for rdmd to support ZIP or 
tarballs directly but I'm sure there are corner cases to consider.


Bye,
norm


Re: Range violation error when reading from a file

2019-06-16 Thread Norm via Digitalmars-d-learn

On Monday, 17 June 2019 at 00:22:23 UTC, Samir wrote:

On Sunday, 16 June 2019 at 23:55:41 UTC, lithium iodate wrote:
There is *very* likely to be a terminating new-line at the end 
of the file (many editors add one without asking!). If that 
the case, the last line seen by the loop will be empty and you 
must not attempt to access any elements.


On Monday, 17 June 2019 at 00:02:37 UTC, aliak wrote:
The fail bit is only set after reading fails. So after you 
read the last line, your eof will still return true, and hence 
your range violation.


H...maybe you and lithium iodate were onto something.

Here is what the file looks like in vim:
> line 1
line 2
line 3
> line 4
line 5
~
~
~

The "5" in the last line is the last character I can put my 
cursor on.


Also, if I run the program below with the same file, I don't 
get any range violation errors:


import std.stdio;
import std.string;

void main() {
File file = File("test.txt");
string line;

while (!file.eof()) {
line = file.readln().strip;
//if (line[0] == '>') { // line 10
//writeln(line[1..$]);
//}
//else {
writeln(line);
//}
}
}

HOWEVER, the output is interesting.  There IS a blank line 
between the last line and the prompt:


$ dmd -run readfile.d
> line 1
line 2
line 3
> line 4
line 5

$

Any suggestions on how to rectify?


You could change the IF to

`if(line.length > 0 && line[0] == '>')`

or use strip itself;

`File("test.txt", "r").byLine.map!(line => 
line.strip(">")).writeln;`


For "> line 1" your code and this above will generate " line 1" 
(note the leading space). To remove that change the string passed 
to `strip` to include a space, e.g.;


`.strip("> ")).writeln;`

bye,
Norm



Re: variant .init value

2019-02-07 Thread Norm via Digitalmars-d-learn

On Thursday, 7 February 2019 at 07:44:17 UTC, Alex wrote:

On Thursday, 7 February 2019 at 07:33:50 UTC, Norm wrote:

[...]


Hmm... found something similar from 2014...
https://issues.dlang.org/show_bug.cgi?id=11864


Thanks, I've added a comment to that bug report.

Cheers,
Norm


variant .init value

2019-02-06 Thread Norm via Digitalmars-d-learn

Hi,

I'm trying to use Variant in a struct and want a default init 
value like so:


---
struct S {
  Variant v = Variant(10);
}
void main() {auto s = S();}

but when I try to build this I get the following error:

dmd2/linux/bin64/../../src/phobos/std/variant.d(661): Error: 
memcpy cannot be interpreted at compile time, because it has no 
available source code

Error: cannot interpret  at compile time
---

I don't particularly need or want this to be available at compile 
time, I really only want the struct to have a default value when 
instantiated at runtime.


Is there a way to do this with a Variant member?

Thanks,
Norm


Re: Singleton in Action?

2019-02-02 Thread Norm via Digitalmars-d-learn

On Saturday, 2 February 2019 at 16:56:45 UTC, Ron Tarrant wrote:

Hi guys,

I ran into another snag this morning while trying to implement 
a singleton. I found all kinds of examples of singleton 
definitions, but nothing about how to put them into practice.


Can someone show me a code example for how one would actually 
use a singleton pattern in D? When I did the same thing in PHP, 
it took me forever to wrap my brain around it, so I'm hoping to 
get there a little faster this time.


Here's the singleton code I've been playing with:

class DSingleton
{
private:
// Cache instantiation flag in thread-local bool
// Thread local
static bool instantiated_;

// Thread global
__gshared DSingleton instance_;

this()
{

} // this()

public:

static DSingleton get()
{
if(!instantiated_)
{
synchronized(DSingleton.classinfo)
{
if(!instance_)
{
instance_ = new DSingleton();
writeln("creating");
}

instantiated_ = true;
}
}
else
{
writeln("not created");
}

return(instance_);

} // DSingleton()

} // class DSingleton

So, my big question is, do I instantiate like this:

DSingleton singleton = new DSingleton;

Or like this:

DSingleton singleton = singleton.get();

And subsequent calls would be...? The same? Using get() only?


Sorry, I should read the post fully before replying, my bad. You 
access the singleton via the get() function whenever you need it. 
It is static so there's no need to create a copy of the instance 
in a "singleton" variable.


DSingleton singleton = new DSingleton; is bad. It bypasses all 
the checks in the "get()" method to ensure it is a singleton and 
outside the module where you defined DSingleton it won't compile.


bye,
norm











Re: Singleton in Action?

2019-02-02 Thread Norm via Digitalmars-d-learn

On Saturday, 2 February 2019 at 16:56:45 UTC, Ron Tarrant wrote:

Hi guys,

I ran into another snag this morning while trying to implement 
a singleton. I found all kinds of examples of singleton 
definitions, but nothing about how to put them into practice.


[...]


If you haven't already been to the d-idioms site it is well worth 
a look:


https://p0nce.github.io/d-idioms/

It has a singleton example that you may find useful.

https://p0nce.github.io/d-idioms/#Leveraging-TLS-for-a-fast-thread-safe-singleton

bye,
norm


Re: Fields with the same name not causing a warning?

2018-11-16 Thread Norm via Digitalmars-d-learn

On Friday, 16 November 2018 at 15:59:14 UTC, Vinay Sajip wrote:

This code should IMO give at least a warning, but it doesn't:

abstract class A {
int kind;
}

[...]



This is not unique to D you can do the same in Java or C++.

bye,
Norm


Re: remove file access denied

2018-09-13 Thread Norm via Digitalmars-d-learn
On Thursday, 13 September 2018 at 23:25:24 UTC, Josphe Brigmo 
wrote:

I am trying to remove a file

remove(filename);

and I get an access denied!

I can remove it from explorer just fine.

I am able to remove other files but there should be no reason 
why the file can't be removed in this case.


All I am doing to mess with the file is reading it's contents 
right before to do a file compare(I am removing the file if it 
is a duplicate).


Does read() lock the file at all? (maybe the lock is persisting 
just long enough to make the remove fail?


Since I can delete the file outside the program and since the 
filename is valid(I copied and pasted it to remove it to 
check), This seems like a D problem.


Do you have the file open when you call remove? If so close the 
file handle before the remove call. If you can post a stripped 
down version of your code it would also help.


bye,
Norm


Re: Optional parameters?

2018-04-01 Thread Norm via Digitalmars-d-learn
On Sunday, 1 April 2018 at 15:54:16 UTC, Steven Schveighoffer 
wrote:
I currently have a situation where I want to have a function 
that accepts a parameter optionally.


I thought maybe Nullable!int might work:

void foo(Nullable!int) {}

void main()
{
   foo(1); // error
   int x;
   foo(x); // error
}

Apparently, I have to manually wrap an int to get it to pass. 
In other languages that support optional types, I can do such 
things, and it works without issues.


I know I can do things like this:

void foo(int x) { return foo(nullable(x)); }

But I'd rather avoid such things if possible. Is there a way 
around this? Seems rather limiting that I can do:


Nullable!int x = 1;

but I can't implicitly convert 1 to a Nullable!int for function 
calls.


-Steve


I don't know if this helps but when I hit this situation I 
usually resort to templates, e.g.


---
void foo(T)(T val = Nullable!int()) if(is(T : int) || is(T == 
Nullable!int))

{
  writeln(val);
}

void main()
{
   foo(1); // prints: 1
   int x;
   foo(x); // prints: 0
   auto val = Nullable!int(5);
   foo(val); // prints: 5
   foo(); // prints: Nullable.null
}
---

Cheers,
Norm


Re: D RAII with postblit disabled

2018-03-29 Thread Norm via Digitalmars-d-learn

On Thursday, 29 March 2018 at 04:16:55 UTC, Adam D. Ruppe wrote:

On Thursday, 29 March 2018 at 04:12:38 UTC, Norm wrote:
Is there a way to do this in D, or does it require special 
"create" functions for every struct that has a RAII-like 
struct as a member?


You'll have to do it all the way up (unless you can use a 
constructor with an argument and call that instead)


OK, thanks.


Re: D RAII with postblit disabled

2018-03-28 Thread Norm via Digitalmars-d-learn

On Tuesday, 27 March 2018 at 02:43:15 UTC, Adam D. Ruppe wrote:

On Tuesday, 27 March 2018 at 02:35:23 UTC, Norm wrote:

What's the best way to do this in D?


I'd also add `@disable this();` and then a `static O make() { 
return O(theAllocator.make!int(99)); }`


than you construct it with that static make function.


OK, that got me over the first hurdle but I still cannot use RAII 
with struct member vars. E.g.


---
struct Resource {
  this() {allocate_something();}
  ~this() {release_something();}
}

struct S {
  Resource resource;
}

---

Is there a way to do this in D, or does it require special 
"create" functions for every struct that has a RAII-like struct 
as a member?



Thanks,
Norm


Re: D RAII with postblit disabled

2018-03-26 Thread Norm via Digitalmars-d-learn

On Tuesday, 27 March 2018 at 02:43:15 UTC, Adam D. Ruppe wrote:

On Tuesday, 27 March 2018 at 02:35:23 UTC, Norm wrote:

What's the best way to do this in D?


I'd also add `@disable this();` and then a `static O make() { 
return O(theAllocator.make!int(99)); }`


than you construct it with that static make function.


Perfect, thanks.


D RAII with postblit disabled

2018-03-26 Thread Norm via Digitalmars-d-learn

Hi All,

What's the best way to do this in D?

E.g.

---
struct O
{
  int* value;
  @disable this(this);
/+
  this()
  {
this.value = theAllocator.make!int(99);
  }
+/
  ~this()
  {
theAllocator.dispose(this.value);
  }
}

O obj = O(); // Ideally this would be allocated but it simply run 
O.init

---

Thanks
Norm


Re: Game and GC

2018-02-22 Thread Norm via Digitalmars-d-learn

On Friday, 23 February 2018 at 01:54:07 UTC, Leonardo wrote:

Hi, I'm new to language and games.
Many people say that GC is bad and can slow down your project 
in some moments.
What can happen if I create a game using D without worrying 
with memory management?

(using full GC)


Have a look at https://github.com/gecko0307/atrium and see how 
memory is handled there.


TBH though every game I've written I have not worried about the 
GC and just code it up. This works fine for 2d games, platformers 
etc. If it ever does bite you can always schedule the pauses 
(they are deterministic in the sense a collect will occur on 
allocation) or do pretty much what every game does in C++/C and 
allocate in pools.


Cheers,
Norm


inout question

2018-02-11 Thread Norm via Digitalmars-d-learn

Hi,

I'm new to D so can someone explain to me what is happening here?


void func(const char* s, char** e) {
import core.stdc.stdlib;
auto result = strtod(s, e);
}

Error: function core.stdc.stdlib.strtod (scope inout(char)* nptr, 
scope inout(char)** endptr) is not callable using argument types 
(const(char*), char**)


I've found I have to use the following:

void func(inout (char)* s, inout(char)** e)


I thought inout was supposed to take const or non-const variants, 
so expected the original const char* s to work.


Thanks,
Norm


deprecation warning after upgrade

2018-02-07 Thread Norm via Digitalmars-d-learn

Hi All,

In my generic code I now get this error, which requires manually 
finding all -a[] array ops, but that is another matter.


$/src/druntime/import/core/internal/arrayop.d-mixin-57(57,20): 
Deprecation: integral promotion not done for -_param_1[pos], use 
'-transition=intpromote' switch or -cast(int)(_param_1[pos])


Is there a way to avoid this in generic code so I can still take 
advantage of array ops? E.g.


this.vec[] = -this.vec[];

Or do I have to do some wrangling like this?

this.vec = this.vec.map!(a => -cast(int)(a)).array.to!(T[]) ??


What would be a good idiomatic way to fix this deprecation issue? 
I do not want to use the flag but make my code better, not mask 
the issue.


Thanks,
Norm