Re: Namespace for a module defined by its import path

[ZombineDev via Digitalmars-d]

On Tuesday, 8 November 2016 at 18:33:13 UTC, Jeff Thompson wrote:
On Tuesday, 8 November 2016 at 17:00:44 UTC, Jeff Thompson 
wrote:
On Wednesday, 26 October 2016 at 17:12:30 UTC, Jonathan Marler 
wrote:
On Wednesday, 26 October 2016 at 09:53:35 UTC, Jeff Thompson 
wrote:

[...]


I've thought about this and have concluded that you can't 
replicate these semantics in D.  Here's 2 solutions though:


[...]


Right now, if a module doesn't have a package statement, the 
module name is the file name with the path and and extension 
stripped off. My problem would be solved by a compiler option 
to keep the path.


... or is there a way to get the path at compile time? I could 
try some mixin magic to construct the package name including 
the path.


I guess this is what you're looking for:
http://dlang.org/changelog/2.072.0.html#__FILE_FULL_PATH__

Re: Array operation with overlapping

[Oleg Gorbunov via Digitalmars-d]

On Tuesday, 8 November 2016 at 14:52:41 UTC, Steven Schveighoffer 
wrote:

On 11/8/16 3:29 AM, Oleg Gorbunov wrote:

I am new in D, but saw some strage behavour.

Overlapping is detected for + and * array operation, but not 
for - and /.





I would say this is a bug. The behavior should be consistent.

-Steve


OK, I'll report this bug at https://issues.dlang.org

Re: Question on syntax

[ketmar via Digitalmars-d-learn]

On Wednesday, 9 November 2016 at 06:28:31 UTC, Jim wrote:

What does it mean when a variable name starts with a '.'


`.a` --> `::a`.

[Issue 16675] New: Overlapping is detected at runtime for + and * array operation, but not for - and /.

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16675

  Issue ID: 16675
   Summary: Overlapping is detected at runtime for + and * array
operation, but not for - and /.
   Product: D
   Version: D2
  Hardware: x86
OS: Windows
Status: NEW
  Severity: normal
  Priority: P1
 Component: druntime
  Assignee: nob...@puremagic.com
  Reporter: olegu...@gmail.com

I am new in D, but saw some strage behaviour.

Overlapping is detected for + and * array operation, but not for - and /.

Ex.

import std.stdio;

void main()
{
int[] slice = [2, 2, 2, 2];
int[] slice2 = slice[0 .. $ - 1];
int[] slice3 = slice[1 .. $];

writeln("slice  before: ", slice);
writeln("slice2 before: ", slice2);
writeln("slice3 before: ", slice3);

enum cmd = "slice3[] = slice2[] + slice3[];";

writeln( "cmd: ", cmd );

mixin( cmd );

writeln("slice  after : ", slice);
writeln("slice2 after : ", slice2);
writeln("slice3 after : ", slice3);
}

When this code is run at 'dlang.org' online compiler

slice  before: [2, 2, 2, 2]
slice2 before: [2, 2, 2]
slice3 before: [2, 2, 2]
cmd: slice3[] = slice2[] + slice3[];
object.Error@(0): Overlapping arrays in vector operation: 8 byte(s) overlap of
12

??:? nothrow @safe void rt.util.array._enforceNoOverlap(const(char[]), ulong,
ulong, const(ulong)) [0x44f7f3]
??:? _arraySliceSliceAddSliceAssign_i [0x44c1b6]
??:? _Dmain [0x4408bb]
??:? _D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv [0x44c8a6]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int
function(char[][])*).tryExec(scope void delegate()) [0x44c7f0]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int
function(char[][])*).runAll() [0x44c862]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int
function(char[][])*).tryExec(scope void delegate()) [0x44c7f0]
??:? _d_run_main [0x44c761]
??:? main [0x44a389]
??:? __libc_start_main [0x40d80a14]

OK

If change + to -

enum cmd = "slice3[] = slice2[] - slice3[];";

When it is run at 'dlang.org'

slice  before: [2, 2, 2, 2]
slice2 before: [2, 2, 2]
slice3 before: [2, 2, 2]
cmd: slice3[] = slice2[] - slice3[];
slice  after : [2, 0, -2, -4]
slice2 after : [2, 0, -2]
slice3 after : [0, -2, -4]

The same behaviour I saw in Windows with DMD2.072.0 and DMD2.069.2

--

Re: Question on syntax

[rikki cattermole via Digitalmars-d-learn]

On 09/11/2016 7:28 PM, Jim wrote:

Hi,

I'm a very experienced C++ programmer, looking at a program written in
D. D is similar enough to C++ and Java that I have no problem
understanding it - except for one thing. I think I may have figured it
out, but I want to confirm my understanding.

What does it mean when a variable name starts with a '.'

Here's an extract from the code:
/// move.d 
module move;

import empire;
import eplayer;
import sub2;

[...]

void updlst(loc_t loc,int type)// update map value at loc
{
   int ty = .typ[.map[loc]];// what's there

... etc.
(loc_t is an alias for int)

Would the equivalent in C or C++ be:

typedef int loc_t;
extern int typ[];
extern int map[];
void updlst( loc_t loc, int type )
{
   int ty = typ[map[loc]];

/// var.d  
module var;
import empire;
import eplayer;

int typ[MAPMAX] = ...etc...
ubyte map[MAPSIZE] = [0,];// reference map

If you need more context, the complete source code is available from
http://www.classicempire.com/


This is a set of syntax that isn't ugh used often (I'm pretty sure I 
know what it is). It just isn't needed.


Empire's code was ported to D during the early days of D1, its 
documentation doesn't come close to best practices let alone the code 
itself.


Example:

int x;

void main() {
x = 8;

import std.stdio;
writeln(.x);
}

Question on syntax

[Jim via Digitalmars-d-learn]

Hi,

I'm a very experienced C++ programmer, looking at a program 
written in D. D is similar enough to C++ and Java that I have no 
problem understanding it - except for one thing. I think I may 
have figured it out, but I want to confirm my understanding.


What does it mean when a variable name starts with a '.'

Here's an extract from the code:
/// move.d 
module move;

import empire;
import eplayer;
import sub2;

[...]

void updlst(loc_t loc,int type) // update map value at loc
{
   int ty = .typ[.map[loc]];// what's there

... etc.
(loc_t is an alias for int)

Would the equivalent in C or C++ be:

typedef int loc_t;
extern int typ[];
extern int map[];
void updlst( loc_t loc, int type )
{
   int ty = typ[map[loc]];

/// var.d  
module var;
import empire;
import eplayer;

int typ[MAPMAX] = ...etc...
ubyte map[MAPSIZE] = [0,];  // reference map

If you need more context, the complete source code is available 
from http://www.classicempire.com/

Re: Is the following code legal?

[Shachar Shemesh via Digitalmars-d]

On 09/11/16 07:02, Stefan Koch wrote:

On Wednesday, 9 November 2016 at 05:00:28 UTC, Shachar Shemesh wrote:

On 08/11/16 17:41, Kagamin wrote:

no


Is this officially declared in the policy? Should I open an issue?

Shachar


Please open an issue.


Ask and thy shall receive.

https://issues.dlang.org/show_bug.cgi?id=16674

[Issue 16674] New: Clarify lifetime of pointer to AA entry

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16674

  Issue ID: 16674
   Summary: Clarify lifetime of pointer to AA entry
   Product: D
   Version: D2
  Hardware: All
OS: All
Status: NEW
  Severity: normal
  Priority: P1
 Component: dlang.org
  Assignee: nob...@puremagic.com
  Reporter: shac...@shemesh.biz

SomeType[SomeOtherType] aa;

...
SomeType* aap = aKey in aa;

The lifetime of aap needs to be clarified. In particular with respect to:
* Removal of aKey from the aa
* Removal of another element from the aa
* Addition of another element to the aa
* Modification of an existing element in the aa with "aa[key] = something"
* Modification of this element in the aa with "aa[aKey] = something".

--

Re: Is the following code legal?

[Stefan Koch via Digitalmars-d]

On Wednesday, 9 November 2016 at 05:00:28 UTC, Shachar Shemesh 
wrote:

On 08/11/16 17:41, Kagamin wrote:

no


Is this officially declared in the policy? Should I open an 
issue?


Shachar


Please open an issue.

Re: Is the following code legal?

[Shachar Shemesh via Digitalmars-d]

On 08/11/16 17:41, Kagamin wrote:

no


Is this officially declared in the policy? Should I open an issue?

Shachar

[Issue 16488] [spec][optimization] broadcast scalar to simd vector

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16488

--- Comment #2 from Walter Bright  ---
https://github.com/dlang/dmd/pull/6248

--

Re: [OT] Re: CTFE Status

[Chris Wright via Digitalmars-d]

On Tue, 08 Nov 2016 11:44:50 -0500, Nick Sabalausky wrote:
> I really wish Google would take that to heart. They seem to make a habit
> of ripping things out *before* having replacements in place.
> 
> I think they just simply love deleting code.

I've seen this more internally than externally. The joke was that there 
are two versions of everything: the deprecated one, and the one that 
doesn't work yet.

Re: CTFE Status

[deadalnix via Digitalmars-d]

On Tuesday, 8 November 2016 at 21:56:32 UTC, Stefan Koch wrote:

Back to CTFE.
The 64Bit bug is fixed.
And now there is one bailout-line less.

I am onto the next bug.
Let's hunt them all down!


https://media.giphy.com/media/FmNXeuoadNTpe/giphy.gif

Re: Question about dsfml.system.err

[Konstantin Kutsevalov via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 19:00:15 UTC, Steven Schveighoffer 
wrote:

On 11/8/16 11:48 AM, Konstantin Kutsevalov wrote:
On Tuesday, 8 November 2016 at 16:34:04 UTC, Konstantin 
Kutsevalov wrote:

ADD:

I tried to open other stream in main()

```
...
import dsfml.system.err;

int main(string[] args)
{
err.open("errors.log", "a");
err.write("test\n");

}
...
```

but as can I see, that hasn't any effect for tcplistener 
module...


OK ... problem with tcplistener solved, just a code mistake. 
But the

question is actual.


I can honestly say, I don't know what dsfml is or any of the 
code you have posted.


-Steve


oh, it's ok because it's all work fine, I just was too 
inattentive.

[Issue 11961] Can't select CRT to link against

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=11961

--- Comment #4 from Manu  ---
Hooray!!

--

[Issue 16673] New: improve cyclic module imports checker

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16673

  Issue ID: 16673
   Summary: improve cyclic module imports checker
   Product: D
   Version: D2
  Hardware: All
OS: All
Status: NEW
  Severity: critical
  Priority: P1
 Component: druntime
  Assignee: nob...@puremagic.com
  Reporter: c...@dawg.eu

There are quite a few projects that broke b/c we fixed the cyclic module
checker.
We should try to relax the conservative import analysis.
It seems that any static ctor/dtor only using symbols from the local module
cannot produce cycles just b/c of that and thus be marked as standalone.

Also cycles coming from imports in unittest blocks could possibly be ignored.

[¹]: https://github.com/dlang/druntime/pull/1602
[²]: https://github.com/dlang/druntime/pull/1602#issuecomment-231527759

--

[Issue 11961] Can't select CRT to link against

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=11961

github-bugzi...@puremagic.com changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |FIXED

--

[Issue 11961] Can't select CRT to link against

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=11961

--- Comment #3 from github-bugzi...@puremagic.com ---
Commits pushed to master at https://github.com/dlang/dmd

https://github.com/dlang/dmd/commit/19b02322007c88a79648cc46f5732f50d42c77fd
fix issue 11961: allow selecting the MS C runtime to link against

https://github.com/dlang/dmd/commit/2c11a0241b88be6eb5416812188c2ca6df196916
Merge pull request #6244 from rainers/select_mscrtlib

fix issue 11961: allow selecting the MS C runtime to link against

--

Re: CTFE Status

[Nordlöw via Digitalmars-d]

On Tuesday, 8 November 2016 at 21:56:32 UTC, Stefan Koch wrote:

I am onto the next bug.
Let's hunt them all down!


Marvellous!

Re: typeof(SortedRange) and is operator

[Jonathan M Davis via Digitalmars-d-learn]

On Tuesday, November 08, 2016 22:33:08 Era Scarecrow via Digitalmars-d-learn 
wrote:
> On Tuesday, 8 November 2016 at 21:14:41 UTC, Jonathan M Davis
>
> wrote:
> > No, as the others have point out, it's not a bug. If anything
> > it's a language design flaw that no one has figured out how to
> > resolve yet.
>
>   The idea of a special struct for code that strips whitespace
> out, or a function that simply does the same thing... Either way
> it would have to be voluntary, preferably at the function level
> writing and not the user level.
>
>   StringNWS? (No White Space) or StringCode?
>
>   Might be something to try... Having a function to call that
> strips it would probably add too much overhead and ugliness
> required by users using the code vs code clarity.
>
>   I'll have to experiment with this later.

The problem is that you can't strip out all whitespace. Some of it matters,
and unless you do something like parse the code in the string, you can't
know whether the whitespace matters or not. Ultimately, it's just easier to
write your strings the same way, which usually is trivial.

- Jonathan M Davis

Re: CTFE Status

[Nick Sabalausky via Digitalmars-d]

On 11/08/2016 05:54 PM, Nick Sabalausky wrote:

On 11/08/2016 02:30 PM, Patrick Schluter wrote:

I describe git not as a vcs but as exacly what Linus Torvalds described
it when he first presented it the Kernel mailing list: a directory
content state recorder optimized for text files.



...that's incapable of comprehending the concept of empty directories,
contrary to every major file system in use.

I never bought the argument about "b/c it tracks content, not files". If
that really did explain the limitation, then it wouldn't be capable of
handling empty *files* either, and yet it does.



(Pardon the OT)

Re: CTFE Status

[Nick Sabalausky via Digitalmars-d]

On 11/08/2016 02:30 PM, Patrick Schluter wrote:

I describe git not as a vcs but as exacly what Linus Torvalds described
it when he first presented it the Kernel mailing list: a directory
content state recorder optimized for text files.



...that's incapable of comprehending the concept of empty directories, 
contrary to every major file system in use.


I never bought the argument about "b/c it tracks content, not files". If 
that really did explain the limitation, then it wouldn't be capable of 
handling empty *files* either, and yet it does.

Re: typeof(SortedRange) and is operator

[Era Scarecrow via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 21:14:41 UTC, Jonathan M Davis 
wrote:
No, as the others have point out, it's not a bug. If anything 
it's a language design flaw that no one has figured out how to 
resolve yet.


 The idea of a special struct for code that strips whitespace 
out, or a function that simply does the same thing... Either way 
it would have to be voluntary, preferably at the function level 
writing and not the user level.


 StringNWS? (No White Space) or StringCode?

 Might be something to try... Having a function to call that 
strips it would probably add too much overhead and ugliness 
required by users using the code vs code clarity.


 I'll have to experiment with this later.

Re: CTFE Status

[Stefan Koch via Digitalmars-d]

Back to CTFE.
The 64Bit bug is fixed.
And now there is one bailout-line less.

I am onto the next bug.
Let's hunt them all down!

Re: CTFE Status

[Iakh via Digitalmars-d]

On Tuesday, 8 November 2016 at 16:40:31 UTC, Nick Sabalausky 
wrote:

On 11/05/2016 11:48 AM, Marc Schütz wrote:
On Saturday, 5 November 2016 at 01:21:48 UTC, Stefan Koch 
wrote:


I recently lost 3 days of work because of my git-skills.


Unless you haven't committed your work yet, almost everything 
in Git can
be undone. Make a copy of your entire project directory 
(including .git)
and then have a look at `git reflog` around the time the 
disaster

happened. It will show you commit IDs that you can check out.


Yea, but unless you're a git-fu master, sometimes figuring out 
how to fix whatever got messed up can lose you 3 days of work ;)


I really want to make a saner CLI front-end for git, but that 
would require learning more about git than I really ever want 
to know :(


http://gitless.com/

Re: typeof(SortedRange) and is operator

[Jonathan M Davis via Digitalmars-d-learn]

On Tuesday, November 08, 2016 13:22:35 RazvanN via Digitalmars-d-learn 
wrote:
> Sorry, I accidentally posted the above message and I don't know
> how to erase it.
> The following post is the complete one:
>
> Given the following code:
>
> int[] arr = [1, 2, 9, 4, 10, 6];
> auto r= sort(arr);
>
> if(is(typeof(r) == SortedRange!(int[], "a  writeln("first if");
>
> if(is(typeof(r) == SortedRange!(int[], "a < b")))
>  writeln("second if");
>
> The program outputs only "second if". I assumed that it should
> have printed both
> ifs. Is this a bug?

No, as the others have point out, it's not a bug. If anything it's a
language design flaw that no one has figured out how to resolve yet.

The big thing here is that lambdas in general are not comparable, even if
they are _exactly_ the same. e.g. this will fail to compile

int[] arr;
auto r1 = sort!((a, b) => a < b)(arr);
auto r2 = sort!((a, b) => a < b)(arr);
static assert(typeof(r1) == typeof(r2));

You get an error like

Error: static assert  (is(SortedRange!(int[], __lambda1) == SortedRange!
(int[], __lambda2))) is false

It doesn't think that __lambda1 and __lambda2 are the same, and that's with
two totally identical lambdas. The language and the compiler simply
do not have a way to do a comparison of lambdas. It's probably possible to
make them do it, but no one has figured out how to do it yet.

String lambdas predate the lambda syntax that I used above, and they have
largely been replaced by that new syntax. But string lambdas are still in
use in part because it's possible to compare strings for equality, and
therefore it's possible to compare string lambdas for equality. But even
then, it's comparing strings for exact equality and not attempting to
decipher the strings. Part of that is because string lambdas are actually
using a library construct - std.functional.binaryFun in this case - in order
to work, so the language is just comparing two instances of the same
instantiation of a template for equality - e.g. binaryFun!"a < b" and
binaryFun!"a < b", which would be equal, or binaryFun!"a < b" and
binaryFun!"a

Re: ModuleInfo linker error when importing std.stdio and using package.d

[Daniel Kozak via Digitalmars-d-learn]

Dne 8.11.2016 v 21:16 Bryce Kellogg via Digitalmars-d-learn napsal(a):


...
Finally, a one line package.d:

public import my_package.my_module;


Change it to:

module my_package;
public import my_package.my_module;

Btw, having class name same as module name is not best way, there could 
be some issues with that

ModuleInfo linker error when importing std.stdio and using package.d

[Bryce Kellogg via Digitalmars-d-learn]

Hi everyone, I'm new to D, and I'm trying to get a handle on the 
correct way to use packages, modules, and importing things. I 
created a simple example, but I'm getting linker errors in weird 
situations. I'm hoping to get some insight into why the error is 
happening and best practices in these sorts of situations.


I've got a simple project set up as follows:
.
├── dub.json
└── source/
├── app.d
└── my_package/
├── my_module.d
└── package.d


The contents of dub.json are pretty simple:


{
"name": "my_package_test",
"description": "A minimal D application.",
"copyright": "Copyright © 2016, kellogg",
"authors": ["kellogg"],
"dependencies": {
}
}


In app.d, all I do is import my package and instantiate my class.

import my_package;
void main() {
my_module m = new my_module();
}


And here's my_module.d

module my_package.my_module;
import std.stdio;
class my_module {
this() {
writeln("Hello World!");
}
}



Finally, a one line package.d:

public import my_package.my_module;


Building this via dub results in the error:

.dub/obj/app.o:(.data._D3app12__ModuleInfoZ[_D3app12__ModuleInfoZ]+0x10): 
undefined reference to `_D10my_package12__ModuleInfoZ'
collect2: error: ld returned 1 exit status
Error: /usr/bin/gcc failed with status: 1
ldc2 failed with exit code 1.


Interestingly, if I remove the 'import std.stdio;' and writeln() 
from my_module.d, it compiles fine. It also works if I move the 
import down to inside the constructor, or replace the import in 
app.d with 'import my_package.my_module;' (side stepping the 
package.d).



To summarize: importing my package via package.d results in a 
linker error if I import std.stdio at the top level in my module. 
I'm wondering: what does this error mean, what does it have to do 
with std.stdio, and am I even using package.d correctly?


Thanks!

Re: CTFE Status

[H. S. Teoh via Digitalmars-d]

On Tue, Nov 08, 2016 at 12:12:34PM -0500, Nick Sabalausky via Digitalmars-d 
wrote:
> On 11/08/2016 11:57 AM, H. S. Teoh via Digitalmars-d wrote:
> > 
> > The thing about git is that at its core, it's really very simple.
> > Dumb, even.  It's basically a program for managing a directed
> > acyclic graph (DAG).  That's all there is to it. The rest is just
> > frills.
> > 
> > Trying to rationalize git in terms of traditional version control
> > systems is what usually causes lots of confusion, incomprehension,
> > and frustration.  To truly grok git, you have to just forget about
> > traditional version control concepts, and think purely in terms of
> > DAGs.  Once you do, everything falls into place and it all makes
> > sense in its own peculiar way (including all the flaws :-P).
> > 
> 
> I don't suppose you have a handy link to an "Understanding Git as a
> DAG manager instead of VCS" document?

Nothing immediately comes to mind, but thanks to Dr. Google, I found
this page that's sorta helpful:

http://ericsink.com/vcbe/html/directed_acyclic_graphs.html

And perhaps these:

http://eagain.net/articles/git-for-computer-scientists/
http://marklodato.github.io/visual-git-guide/index-en.html

Or maybe I should write my own article about git being based on a DAG.
:-P


T

-- 
Leather is waterproof.  Ever see a cow with an umbrella?

Re: CTFE Status

[Patrick Schluter via Digitalmars-d]

On Tuesday, 8 November 2016 at 16:57:27 UTC, H. S. Teoh wrote:
On Tue, Nov 08, 2016 at 11:40:31AM -0500, Nick Sabalausky via 
Digitalmars-d wrote:

On 11/05/2016 11:48 AM, Marc Schütz wrote:
> On Saturday, 5 November 2016 at 01:21:48 UTC, Stefan Koch 
> wrote:
> > 
> > I recently lost 3 days of work because of my git-skills.
> 
> Unless you haven't committed your work yet, almost 
> everything in Git can be undone. Make a copy of your entire 
> project directory (including .git) and then have a look at 
> `git reflog` around the time the disaster happened. It will 
> show you commit IDs that you can check out.


Yea, but unless you're a git-fu master, sometimes figuring out 
how to fix whatever got messed up can lose you 3 days of work 
;)


I really want to make a saner CLI front-end for git, but that 
would require learning more about git than I really ever want 
to know :(


If you study carefully the data model of git you will then come 
to the conclusion that its CLI is not that bad.


The thing about git is that at its core, it's really very 
simple. Dumb, even.  It's basically a program for managing a 
directed acyclic graph (DAG).  That's all there is to it. The 
rest is just frills.


Trying to rationalize git in terms of traditional version 
control systems is what usually causes lots of confusion, 
incomprehension, and frustration.  To truly grok git, you have 
to just forget about traditional version control concepts, and 
think purely in terms of DAGs. Once you do, everything falls 
into place and it all makes sense in its own peculiar way 
(including all the flaws :-P).


I describe git not as a vcs but as exacly what Linus Torvalds 
described it when he first presented it the Kernel mailing list: 
a directory content state recorder optimized for text files. The 
DAG is already an abstraction above i.e. a mean to that end.

Re: CTFE Status

[Antonio Corbi via Digitalmars-d]

On Tuesday, 8 November 2016 at 17:12:34 UTC, Nick Sabalausky 
wrote:

On 11/08/2016 11:57 AM, H. S. Teoh via Digitalmars-d wrote:

[...]


I don't suppose you have a handy link to an "Understanding Git 
as a DAG manager instead of VCS" document?


Hi Nick,

Maybe this one is useful for you:

http://eagain.net/articles/git-for-computer-scientists/

Antonio

Re: Question about dsfml.system.err

[Steven Schveighoffer via Digitalmars-d-learn]

On 11/8/16 11:48 AM, Konstantin Kutsevalov wrote:

On Tuesday, 8 November 2016 at 16:34:04 UTC, Konstantin Kutsevalov wrote:

ADD:

I tried to open other stream in main()

```
...
import dsfml.system.err;

int main(string[] args)
{
err.open("errors.log", "a");
err.write("test\n");

}
...
```

but as can I see, that hasn't any effect for tcplistener module...


OK ... problem with tcplistener solved, just a code mistake. But the
question is actual.


I can honestly say, I don't know what dsfml is or any of the code you 
have posted.


-Steve

Re: Why doesn't std.variant.visit automatically call the provided delegates?

[Steven Schveighoffer via Digitalmars-d]

On 11/5/16 4:22 PM, Adam D. Ruppe wrote:

On Saturday, 5 November 2016 at 20:15:14 UTC, Kapps wrote:

That feels like it should be a compiler warning.


I'm now of the opinion that the {} delegates should be deprecated
(instead use () {} delegates)... this comes up a lot and there's a few
other places too where it is a pain... and it isn't that worth keeping imo.


I created an enhancement request, as I didn't see any in the issue 
tracker already.


https://issues.dlang.org/show_bug.cgi?id=16672

-Steve

[Issue 16670] std.variant visiting allows type parameters not held by variant

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16670

--- Comment #1 from Nick Treleaven  ---
I have a fix working locally, will submit a PR soon.

--

Re: Namespace for a module defined by its import path

[Jeff Thompson via Digitalmars-d]

On Tuesday, 8 November 2016 at 17:00:44 UTC, Jeff Thompson wrote:
On Wednesday, 26 October 2016 at 17:12:30 UTC, Jonathan Marler 
wrote:
On Wednesday, 26 October 2016 at 09:53:35 UTC, Jeff Thompson 
wrote:

[...]


I've thought about this and have concluded that you can't 
replicate these semantics in D.  Here's 2 solutions though:


[...]


Right now, if a module doesn't have a package statement, the 
module name is the file name with the path and and extension 
stripped off. My problem would be solved by a compiler option 
to keep the path.


... or is there a way to get the path at compile time? I could 
try some mixin magic to construct the package name including the 
path.

[Issue 16670] std.variant visiting allows type parameters not held by variant

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16670

Nick Treleaven  changed:

   What|Removed |Added

   Assignee|nob...@puremagic.com|n...@geany.org

--

Re: CTFE Status

[Nick Sabalausky via Digitalmars-d]

On 11/08/2016 11:57 AM, H. S. Teoh via Digitalmars-d wrote:


The thing about git is that at its core, it's really very simple. Dumb,
even.  It's basically a program for managing a directed acyclic graph
(DAG).  That's all there is to it. The rest is just frills.

Trying to rationalize git in terms of traditional version control
systems is what usually causes lots of confusion, incomprehension, and
frustration.  To truly grok git, you have to just forget about
traditional version control concepts, and think purely in terms of DAGs.
Once you do, everything falls into place and it all makes sense in its
own peculiar way (including all the flaws :-P).



I don't suppose you have a handy link to an "Understanding Git as a DAG 
manager instead of VCS" document?

Re: What is the right level of abstractions for D?

[Nick Sabalausky via Digitalmars-d]

On 11/07/2016 02:00 AM, Danni Coy via Digitalmars-d wrote:


When I mean high quality I mean competitive with Qt (the current least bad
cross platform toolkit), DLangUI gets compared to the Java UI offerings
which leaves me somewhat cold. I have never met a java program with a UI I
liked.



Yea. DLangUI sounds nice and all to me, but the lack of native UI 
backend is a nonstarter.


Have you tried QtE5? I admit I haven't had a chance to try it out yet 
myself, but from what I can tell, it looks like what I've been wanting 
in a D GUI lib: https://github.com/MGWL/QtE5




In the former case it might be nice to have some syntactic sugar in the way
that maxscript does.

for a in group where a.count > 0 do (



I know I'm not a group 3 person, but I find that difficult to read, and 
its similarity to SQL's undisciplined syntax frightens me.



is easier to approach than

foreach (a; group.filter!(a.count > 0)()) {

but that is a fairly minor qwibble.



I like to "stack" for/foreach/if's:

foreach(group; setOfGroups)
foreach(a; group)
if(a.count > 0)
{
//...
}

Re: CTFE Status

[H. S. Teoh via Digitalmars-d]

On Tue, Nov 08, 2016 at 11:40:31AM -0500, Nick Sabalausky via Digitalmars-d 
wrote:
> On 11/05/2016 11:48 AM, Marc Schütz wrote:
> > On Saturday, 5 November 2016 at 01:21:48 UTC, Stefan Koch wrote:
> > > 
> > > I recently lost 3 days of work because of my git-skills.
> > 
> > Unless you haven't committed your work yet, almost everything in Git
> > can be undone. Make a copy of your entire project directory
> > (including .git) and then have a look at `git reflog` around the
> > time the disaster happened. It will show you commit IDs that you can
> > check out.
> 
> Yea, but unless you're a git-fu master, sometimes figuring out how to
> fix whatever got messed up can lose you 3 days of work ;)
> 
> I really want to make a saner CLI front-end for git, but that would
> require learning more about git than I really ever want to know :(

The thing about git is that at its core, it's really very simple. Dumb,
even.  It's basically a program for managing a directed acyclic graph
(DAG).  That's all there is to it. The rest is just frills.

Trying to rationalize git in terms of traditional version control
systems is what usually causes lots of confusion, incomprehension, and
frustration.  To truly grok git, you have to just forget about
traditional version control concepts, and think purely in terms of DAGs.
Once you do, everything falls into place and it all makes sense in its
own peculiar way (including all the flaws :-P).


T

-- 
It only takes one twig to burn down a forest.

[Issue 16672] New: Deprecate "block only" delegate syntax

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16672

  Issue ID: 16672
   Summary: Deprecate "block only" delegate syntax
   Product: D
   Version: D2
  Hardware: All
OS: All
Status: NEW
  Severity: enhancement
  Priority: P1
 Component: dmd
  Assignee: nob...@puremagic.com
  Reporter: schvei...@yahoo.com

Currently, this code:

{int x = 5; return x;}

Can either be a block (if written by itself), or a delegate, if used in an
expression. e.g.:

auto dg = {int x = 5; return x;}

This particular ambiguity becomes horrible if combined with the single
expression lambda syntax:

auto x = (a => {return a;})(1);

What this looks like is an immediately called lambda that returns its parameter
(a). However, what it *REALLY* returns is a delegate that will return 1 when
called.

This confusion leads to many problems, as people never want this result.

The solution is simple -- deprecate the shortened brace syntax, and require ()
before the braces. e.g.:

auto dg = () {int x = 5; return x; }

Without the parens, the above should be an error. The drawback is obviously
that one needs to insert parentheses wherever a no-param delegate needs
declaring. The cost of doing this, IMO, is low compared to the regular reports
we get of the x => {...} syntax "not working".

--

Re: Namespace for a module defined by its import path

[Jeff Thompson via Digitalmars-d]

On Wednesday, 26 October 2016 at 17:12:30 UTC, Jonathan Marler 
wrote:
On Wednesday, 26 October 2016 at 09:53:35 UTC, Jeff Thompson 
wrote:

[...]


I've thought about this and have concluded that you can't 
replicate these semantics in D.  Here's 2 solutions though:


[...]


Right now, if a module doesn't have a package statement, the 
module name is the file name with the path and and extension 
stripped off. My problem would be solved by a compiler option to 
keep the path.

Re: Optimizing std.regex

[Dmitry Olshansky via Digitalmars-d-announce]

On 11/8/16 12:23 PM, Chris wrote:

On Monday, 7 November 2016 at 13:13:24 UTC, Mike Parker wrote:

Dmitry mentioned here in the forums not long ago that he had squeezed
some big performance improvements out of std.regex. His post on the D
Blog describes how he managed to do it through an algorithmic
optimization.

The post:
https://dlang.org/blog/2016/11/07/big-performance-improvement-for-std-regex/


Reddit:
https://www.reddit.com/r/programming/comments/5bm1bc/from_the_d_blog_optimizing_stdregex/



Great job! Would it be possible (or indeed worth it) to create a similar
engine for general text processing / string handling?


Depends on what do you mean general - hard to find something more 
general then regex for text processing. Or do you mean using Bit NFA 
directly without the regex layer? It should be possible, however one 
needs to keep in mind the limitation - 32 or 64 states in total.


---
Dmitry Olshansky

Re: Why doesn't std.variant.visit automatically call the provided delegates?

[Steven Schveighoffer via Digitalmars-d]

On 11/8/16 11:31 AM, Nick Sabalausky wrote:

On 11/05/2016 04:22 PM, Adam D. Ruppe wrote:

On Saturday, 5 November 2016 at 20:15:14 UTC, Kapps wrote:

That feels like it should be a compiler warning.


I'm now of the opinion that the {} delegates should be deprecated
(instead use () {} delegates)... this comes up a lot and there's a few
other places too where it is a pain... and it isn't that worth keeping
imo.


I didn't even know you could create a delegate with just {} and no
parens. Kinda confusing since, normally, {} by itself creates a scope,
not a delegate.


Indeed:

  {int x = foo; return x;} // scope

auto dg = {int x = foo; return x;} // delegate

The requirements seem to be that you have to use the {} syntax as an 
expression instead of a block.


omitting the initial parentheses seems like a really low benefit to 
having such confusing ambiguity. And of course, it leads to the horrible 
examples shown by OP.


-Steve

Re: Question about dsfml.system.err

[Konstantin Kutsevalov via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 16:34:04 UTC, Konstantin 
Kutsevalov wrote:

ADD:

I tried to open other stream in main()

```
...
import dsfml.system.err;

int main(string[] args)
{
err.open("errors.log", "a");
err.write("test\n");

}
...
```

but as can I see, that hasn't any effect for tcplistener 
module...


OK ... problem with tcplistener solved, just a code mistake. But 
the question is actual.

[OT] Re: CTFE Status

[Nick Sabalausky via Digitalmars-d]

On 11/05/2016 04:57 PM, Andrei Alexandrescu wrote:


That's good thinking - leave short term to the short term and long term
to the long term. As the Romanian proverb goes: "Don't sell the skin of
the bear before you shoot it." -- Andrei



I really wish Google would take that to heart. They seem to make a habit 
of ripping things out *before* having replacements in place.


I think they just simply love deleting code.

Re: CTFE Status

[Nick Sabalausky via Digitalmars-d]

On 11/05/2016 11:48 AM, Marc Schütz wrote:

On Saturday, 5 November 2016 at 01:21:48 UTC, Stefan Koch wrote:


I recently lost 3 days of work because of my git-skills.


Unless you haven't committed your work yet, almost everything in Git can
be undone. Make a copy of your entire project directory (including .git)
and then have a look at `git reflog` around the time the disaster
happened. It will show you commit IDs that you can check out.


Yea, but unless you're a git-fu master, sometimes figuring out how to 
fix whatever got messed up can lose you 3 days of work ;)


I really want to make a saner CLI front-end for git, but that would 
require learning more about git than I really ever want to know :(

Re: Question about dsfml.system.err

[Konstantin Kutsevalov via Digitalmars-d-learn]

ADD:

I tried to open other stream in main()

```
...
import dsfml.system.err;

int main(string[] args)
{
err.open("errors.log", "a");
err.write("test\n");

}
...
```

but as can I see, that hasn't any effect for tcplistener module...

Re: Why doesn't std.variant.visit automatically call the provided delegates?

[Nick Sabalausky via Digitalmars-d]

On 11/05/2016 04:22 PM, Adam D. Ruppe wrote:

On Saturday, 5 November 2016 at 20:15:14 UTC, Kapps wrote:

That feels like it should be a compiler warning.


I'm now of the opinion that the {} delegates should be deprecated
(instead use () {} delegates)... this comes up a lot and there's a few
other places too where it is a pain... and it isn't that worth keeping imo.


I didn't even know you could create a delegate with just {} and no 
parens. Kinda confusing since, normally, {} by itself creates a scope, 
not a delegate.

Question about dsfml.system.err

[Konstantin Kutsevalov via Digitalmars-d-learn]

I need to see errors from dsfml.system.err, but it doesn't write 
to terminal as I expected.


The general problem is that I cannot listen any port by 
tcplistener. And listen method is:


Status accept(TcpSocket socket)
{
import dsfml.system.string;
Status toReturn = sfTcpListener_accept(sfPtr, socket.sfPtr);
err.write(dsfml.system.string.toString(sfErr_getOutput()));
return toReturn;
}

so, as you can see, there is "err.write". I need to see which 
error is wrining ro "err"...

Is it possible to redeclate "err" File() object?

:(

Re: typeof(SortedRange) and is operator

[Ali Çehreli via Digitalmars-d-learn]

On 11/08/2016 07:06 AM, RazvanN wrote:

>> `SortedRange!(int[], "a> because the arguments to the templates differ i.e. "a>
>> Is this a bug? no. is it weird, confusing and unintuitive? yes.
>
> I think that lambda comparison should be done logically (by that I mean:
> what the function actually computes) not literally.

Still, from the point of view of the language string template parameters 
are not necessarily lambdas. The fact that a particular template may mix 
them in and use in similar fashion cannot change it.


> For example: it is a
> mistake to consider the 2 two lambda functions different just because
> one expression has more white spaces.

Possibly but again, the language not necessarily knows what that string 
means. The whitespace my be significant.


> Also "a < b" is the same lambda
> function as "e < d"; considering these 2 functions to not be equal is a
> mistake.

So-called "string lambdas" are actually pretty weird. You know that "e < 
d" cannot work with SortedRange, right? The string is actually mixed-in; 
so you have to know what the surrounding code expects and provide a 
matching string. In this case, you have to provide 'a' and 'b'.


Ali

Re: Trailing catch on function?

[Manu via Digitalmars-d]

On 8 November 2016 at 12:50, Mike Parker via Digitalmars-d <
digitalmars-d@puremagic.com> wrote:

> On Tuesday, 8 November 2016 at 01:50:26 UTC, Walter Bright wrote:
>
>> On 11/7/2016 4:12 PM, Robert burner Schadek wrote:
>>
>>> On Monday, 7 November 2016 at 23:37:18 UTC, Walter Bright wrote:
>>>
 void callback() nothrow
 {
 scope (failure)
 {
 ...log error or abort...
 }
 ...lots of code...
 }

>>>
>>> Who to get the Exception thrown in the scope(failure)
>>>
>>
>> You don't. The exception is also rethrown, so it isn't an exact
>> replacement. (The 'nothrow' is a mistake on my part.)
>>
>
> In this specific case, a function used as a callback for a C API, it
> really ought to be nothrow because of the inconsistent behavior with
> propagating exceptions across language boundaries. scope(exit) just isn't
> useful here.
>

It's not strictly useful for interaction with C, it would be equally useful
in the situation where a nothrow function returns an error code or
something. The tail-catch block could do the translation and return the
error, and it would be in a nice place separate from the main function body.

Re: Trailing catch on function?

[Manu via Digitalmars-d]

On 8 November 2016 at 09:37, Walter Bright via Digitalmars-d <
digitalmars-d@puremagic.com> wrote:

> On 11/6/2016 8:30 PM, Manu via Digitalmars-d wrote:
>
>> Hey people, I'm passing lots of D function pointers to C, and naturally,
>> the C
>> api expects the fp signatures are all nothrow.
>>
>> Which means, my D functions all look like this:
>>
>> void callback() nothrow
>> {
>> try
>> {
>> ...lots of code...
>> }
>> catch (Exception e)
>> {
>> ...log error or abort...
>> }
>> }
>>
>>
>> I'm generally annoyed by all the extra indentation.
>>
>
> void callback() nothrow
> {
> scope (failure)
> {
> ...log error or abort...
> }
> ...lots of code...
> }
>

scope(failure) doesn't catch... how is that function nothrow?

Re: Thread (spawn) for object's method

[Konstantin Kutsevalov via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 06:40:32 UTC, Basile B. wrote:
On Monday, 7 November 2016 at 16:15:44 UTC, Konstantin 
Kutsevalov wrote:

Is there a way to make new thread for class method?

E.g. I have some class and I need to run one of them method in 
new thread.


I found wxamples only with function...



import core.thread;

class Foo
{
void method(){}
}

void main()
{
Foo foo = new Foo;
Thread t = new Thread();
}


oh, so simple... :) thank you!

Re: Is the following code legal?

[Kagamin via Digitalmars-d]

no

Re: how to debug memory errors

[bachmeier via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 14:55:53 UTC, Steven Schveighoffer 
wrote:


Indeed, you should not. I'm saying this type of error can 
explain the observed behavior.


The original post I responded to said "I don't know if the 
double free problem is related to this."


-Steve


Okay. I thought maybe there was a gotcha that I wasn't aware of.

Re: typeof(SortedRange) and is operator

[RazvanN via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 13:59:19 UTC, Nicholas Wilson 
wrote:

On Tuesday, 8 November 2016 at 13:22:35 UTC, RazvanN wrote:
Sorry, I accidentally posted the above message and I don't 
know how to erase it.


You can't, this is a mailing list not a forum.


The following post is the complete one:

Given the following code:

int[] arr = [1, 2, 9, 4, 10, 6];
auto r= sort(arr);

if(is(typeof(r) == SortedRange!(int[], "a expression` lambdas don't work 
at all in template expressions.


`SortedRange!(int[], "a

Re: how to debug memory errors

[Steven Schveighoffer via Digitalmars-d-learn]

On 11/8/16 6:26 AM, bachmeier wrote:

On Monday, 7 November 2016 at 02:22:35 UTC, Steven Schveighoffer wrote:

Imagine a resource wrapper like so:

class Foo
{
   int *mem;
   this() { mem = cast(int *)malloc(int.sizeof); }
   ~this() { .free(mem); }
}

Now, you have a problem if you do something like this:

class Bar
{
   Foo foo;
   ~this() { delete foo; }
}



Is there a valid use case for something like this? Why would you want to
do anything inside ~this with GC memory?


Indeed, you should not. I'm saying this type of error can explain the 
observed behavior.


The original post I responded to said "I don't know if the double free 
problem is related to this."


-Steve

Re: Array operation with overlapping

[Steven Schveighoffer via Digitalmars-d]

On 11/8/16 3:29 AM, Oleg Gorbunov wrote:

I am new in D, but saw some strage behavour.

Overlapping is detected for + and * array operation, but not for - and /.




I would say this is a bug. The behavior should be consistent.

-Steve

Re: Is the following code legal?

[Steven Schveighoffer via Digitalmars-d]

On 11/8/16 7:58 AM, Shachar Shemesh wrote:

SomeStruct[int] aa;



SomeStruct* aap = v in aa;
aa.remove(v);
writeln(aap);



It currently will work. At some point in the past, this did NOT work, as 
we were proactively freeing the data.


I don't know if the policy is that this is officially supported or not. 
Hence, I don't know the answer to the question "is it legal".


-Steve

Re: typeof(SortedRange) and is operator

[WebFreak001 via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 13:59:19 UTC, Nicholas Wilson 
wrote:

You can't, this is a mailing list not a forum.


 > forum.dlang.org

Re: typeof(SortedRange) and is operator

[Nicholas Wilson via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 13:22:35 UTC, RazvanN wrote:
Sorry, I accidentally posted the above message and I don't know 
how to erase it.


You can't, this is a mailing list not a forum.


The following post is the complete one:

Given the following code:

int[] arr = [1, 2, 9, 4, 10, 6];
auto r= sort(arr);

if(is(typeof(r) == SortedRange!(int[], "a expression` lambdas don't work at 
all in template expressions.


`SortedRange!(int[], "a

Re: calling convention optimisation & const/immutable ref

[Matthias Bentrup via Digitalmars-d]

On Tuesday, 8 November 2016 at 12:56:10 UTC, Johan Engelen wrote:

On Monday, 7 November 2016 at 16:48:55 UTC, John Colvin wrote:

[...]


This reminds me of an LLVM presentation by Chandler, mentioning 
that passing by reference may hamper the optimization of code 
(because memory becomes involved). I don't think he gave a 
clear example, but one thing I can think of is potential 
aliasing:
void foo(ref LargeThing a, ref LargeThing b), where a and b may 
alias partly.
To do the "ref" optimization for _all_ large function 
parameters per default sounds like a bad idea.


Also, how would I turn the optimization off (I guess 
extern(C++) would do that?)? What if my function needs a local 
copy (say, in multithreaded stuff), and I want that copy to be 
const?


-Johan


Aliasing is not an issue when LargeThing is immutable, is it ?

Re: typeof(SortedRange) and is operator

[RazvanN via Digitalmars-d-learn]

Sorry, I accidentally posted the above message and I don't know 
how to erase it.

The following post is the complete one:

Given the following code:

int[] arr = [1, 2, 9, 4, 10, 6];
auto r= sort(arr);

if(is(typeof(r) == SortedRange!(int[], "a

typeof(SortedRange) and is operator

[RazvanN via Digitalmars-d-learn]

Given the following code:

int[] arr = [1, 2, 9, 4, 10, 6];
auto r= sort(arr);

if(is(typeof(r) == SortedRange!(int[], "a

Re: Is the following code legal?

[Shachar Shemesh via Digitalmars-d]

On 08/11/16 14:58, Shachar Shemesh wrote:

SomeStruct[int] aa;

...

SomeStruct* aap = v in aa;
aa.remove(v);
writeln(aap);



That last line is, of course: "writeln(*aap);"

Shachar

Is the following code legal?

[Shachar Shemesh via Digitalmars-d]

SomeStruct[int] aa;

...

SomeStruct* aap = v in aa;
aa.remove(v);
writeln(aap);

Re: calling convention optimisation & const/immutable ref

[Johan Engelen via Digitalmars-d]

On Monday, 7 November 2016 at 16:48:55 UTC, John Colvin wrote:
Some people use ref for performance to prevent the copying that 
must occur when passing by value.


This reminds me of an LLVM presentation by Chandler, mentioning 
that passing by reference may hamper the optimization of code 
(because memory becomes involved). I don't think he gave a clear 
example, but one thing I can think of is potential aliasing:
void foo(ref LargeThing a, ref LargeThing b), where a and b may 
alias partly.
To do the "ref" optimization for _all_ large function parameters 
per default sounds like a bad idea.


Also, how would I turn the optimization off (I guess extern(C++) 
would do that?)? What if my function needs a local copy (say, in 
multithreaded stuff), and I want that copy to be const?


-Johan

[Issue 14511] Profiler does not work with multithreaded programs

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14511

Alex  changed:

   What|Removed |Added

 CC||sascha.or...@gmail.com

--- Comment #6 from Alex  ---
After an update from 2.071.2 to 2.072.0 
a seg fault with the profile option on a mac appear with the following example 

void main() {}
void f()
{
import core.atomic: atomicOp;
shared size_t workUnitIndex;
atomicOp!"+="(workUnitIndex, 1);
}

which does not appear with the prior version of atomic.d 

Many thanks to ag0aep6g for helping with the code.

--

Re: how to debug memory errors

[bachmeier via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 11:53:37 UTC, Era Scarecrow wrote:

On Tuesday, 8 November 2016 at 11:26:55 UTC, bachmeier wrote:


Is there a valid use case for something like this? Why would 
you want to do anything inside ~this with GC memory?


 If we assume it's a C++ attachment/library/object using 
different memory allocation?


I'm not sure what "it's" is referring to in your statement. In 
the example, Foo wraps manually allocated memory that is freed 
when Foo goes out of scope. If the goal is to free the memory in 
Foo when Bar goes out of scope, that can be done without error by 
rewriting Foo. Therefore I'm not understanding how this situation 
can arise in real world code (I'm sure it can, though, which is 
why I'm asking).

[Issue 16671] std.variant visiting functions should pass file, line to VariantException

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16671

Nick Treleaven  changed:

   What|Removed |Added

   Keywords||pull
URL||https://github.com/dlang/ph
   ||obos/pull/4892

--

[Issue 16671] New: std.variant visiting functions should pass file, line to VariantException

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16671

  Issue ID: 16671
   Summary: std.variant visiting functions should pass file, line
to VariantException
   Product: D
   Version: D2
  Hardware: x86
OS: Windows
Status: NEW
  Severity: enhancement
  Priority: P1
 Component: phobos
  Assignee: nob...@puremagic.com
  Reporter: n...@geany.org

When Algebraic().visit (or tryVisit) throws an exception, the file and line
number are always internal to std.variant. It should use the caller's __FILE__,
__LINE__.

--

Re: how to debug memory errors

[Era Scarecrow via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 11:26:55 UTC, bachmeier wrote:


Is there a valid use case for something like this? Why would 
you want to do anything inside ~this with GC memory?


 If we assume it's a C++ attachment/library/object using 
different memory allocation?

[Issue 16670] New: std.variant visiting allows type parameters not held by variant

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16670

  Issue ID: 16670
   Summary: std.variant visiting allows type parameters not held
by variant
   Product: D
   Version: D2
  Hardware: x86
OS: Windows
Status: NEW
  Severity: minor
  Priority: P1
 Component: phobos
  Assignee: nob...@puremagic.com
  Reporter: n...@geany.org

Algebraic!(size_t, string) variant;
variant.visit!((void*)=>0, (size_t s)=>0, (string s)=>0);
variant.tryVisit!((void*)=>0);
variant.tryVisit!((bool)=>0);

None of the 3 visiting functions should compile because `variant` can't hold
void* or bool. Should be statically prevented to catch bugs.

--

Re: Trailing catch on function?

[Daniel N via Digitalmars-d]

On Tuesday, 8 November 2016 at 11:24:59 UTC, Anonymouse wrote:
You can eat the exception by returning in the scope guard. 
Since it seems to trigger on Throwables it also eats Errors, 
sadly.




Interesting!

Considering this works:
scope(failure) { abort(); return; }

I had expected this to work also:
scope(failure) abort();

But I guess D lacks support for noreturn attribute on abort?

RCString Time frame

[Chris via Digitalmars-d]

I'm planning to rewrite / improve some of my text handling 
modules. Before I do so, however, I'd like to know when RCString 
will be introduced (roughly)?


And how will it handle Unicode, or auto-decode to be precise. As 
far as I remember, RCString wants to get rid of it.

Re: "Multiple alias this" status?

[Picaud Vincent via Digitalmars-d]

Thank you for your answer, that is a sad news.

Re: how to debug memory errors

[bachmeier via Digitalmars-d-learn]

On Monday, 7 November 2016 at 02:22:35 UTC, Steven Schveighoffer 
wrote:

Imagine a resource wrapper like so:

class Foo
{
   int *mem;
   this() { mem = cast(int *)malloc(int.sizeof); }
   ~this() { .free(mem); }
}

Now, you have a problem if you do something like this:

class Bar
{
   Foo foo;
   ~this() { delete foo; }
}



Is there a valid use case for something like this? Why would you 
want to do anything inside ~this with GC memory?

Re: Optimizing std.regex

[Chris via Digitalmars-d-announce]

On Monday, 7 November 2016 at 13:13:24 UTC, Mike Parker wrote:
Dmitry mentioned here in the forums not long ago that he had 
squeezed some big performance improvements out of std.regex. 
His post on the D Blog describes how he managed to do it 
through an algorithmic optimization.


The post:
https://dlang.org/blog/2016/11/07/big-performance-improvement-for-std-regex/

Reddit:
https://www.reddit.com/r/programming/comments/5bm1bc/from_the_d_blog_optimizing_stdregex/


Great job! Would it be possible (or indeed worth it) to create a 
similar engine for general text processing / string handling?

Re: Trailing catch on function?

[Anonymouse via Digitalmars-d]

On Tuesday, 8 November 2016 at 01:50:26 UTC, Walter Bright wrote:

Who to get the Exception thrown in the scope(failure)


You don't. The exception is also rethrown, so it isn't an exact 
replacement. (The 'nothrow' is a mistake on my part.)


You can eat the exception by returning in the scope guard. Since 
it seems to trigger on Throwables it also eats Errors, sadly.


void fun() nothrow
{
scope(failure)
{
// cleanup logic
return;
}

throw new Exception("I don't get rethrown");
}

Re: calling convention optimisation & const/immutable ref

[Marc Schütz via Digitalmars-d]

On Monday, 7 November 2016 at 16:48:55 UTC, John Colvin wrote:
Some people use ref for performance to prevent the copying that 
must occur when passing by value. I propose a small 
optimisation to make this unnecessary in a bunch of cases.


At the ABI level (no change in language semantics), if a given 
parameter would otherwise be copied and passed on the stack:

1) immutable parameters to all functions are passed by reference
2) const parameters to pure functions are passed by reference, 
if and only if all other parameters - including any implicit 
this parameter - contain no mutable references (otherwise 
"weakly" pure functions could modify the data we are now 
referring to instead of having copied, changing semantics).


If this is done, it should only apply to parameters larger than a 
certain size, say 2 words. Indirect memory access comes with its 
own cost that is often larger than that of copying.

Re: "Multiple alias this" status?

[Daniel Kozak via Digitalmars-d]

Dne 8.11.2016 v 11:37 Picaud Vincent via Digitalmars-d napsal(a):


Hi All,

I just started to learn a little bit of D.

I read this thread
https://github.com/dlang/dmd/pull/3998

about "Multiple alias this".

I think this feature is very handy, but dmd and gcd compilers complain 
that "there must be only one" alias this.


It is not clear to me if this feature is not available yet or if there 
was a change in the language specifications (Andrei Alexandrescu book 
mentions "§6.13 Multiple subtyping") ?


Does anyone has more information concerning that?

Thanks in advance,
Vincent
This feature has never been part of any D compiler.  As you can see 
there is a pull request 3998 which trying to add this to D frontend, but 
there is no activity for a few months.

Re: New to D and mimicking C++ : how to implement std::integral_constant<>?

[Picaud Vincent via Digitalmars-d-learn]

Hi Basile,
Thank you for your code, it allowed me to grasp a little bit more 
about how to do things in D.

Vincent

"Multiple alias this" status?

[Picaud Vincent via Digitalmars-d]

Hi All,

I just started to learn a little bit of D.

I read this thread
https://github.com/dlang/dmd/pull/3998

about "Multiple alias this".

I think this feature is very handy, but dmd and gcd compilers 
complain that "there must be only one" alias this.


It is not clear to me if this feature is not available yet or if 
there was a change in the language specifications (Andrei 
Alexandrescu book mentions "§6.13 Multiple subtyping") ?


Does anyone has more information concerning that?

Thanks in advance,
Vincent

Re: Trailing catch on function?

[Robert burner Schadek via Digitalmars-d]

On Tuesday, 8 November 2016 at 01:50:26 UTC, Walter Bright wrote:
You don't. The exception is also rethrown, so it isn't an exact 
replacement. (The 'nothrow' is a mistake on my part.)


this:

scope(failure, Exception e) {
// Do something with e
}

would be nice

Re: how to debug memory errors

[Lodovico Giaretta via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 07:39:12 UTC, Era Scarecrow wrote:

On Tuesday, 8 November 2016 at 06:04:59 UTC, thedeemon wrote:
On Tuesday, 8 November 2016 at 05:36:22 UTC, Era Scarecrow 
wrote:


 Hmmm.. I had the impression that if something was referenced 
by another object, then it couldn't be collected,


Another *live* object, I.e. reachable from globals and stack. 
If you have a big tree and it becomes unreachable (you only 
had a pointer to its root and you nulled it), then this whole 
tree becomes garbage, and its nodes and leafs will be 
collected in unpredictable order, with destructors being run 
in unpredictable order, even when these dead nodes reference 
each other.


 And I can't help but hope it would start at the largest/base 
object and work it's way up. Or the largest object and then 
work it's way down. Alright...


One of the reasons it is not specified is that very often the 
hierarchy is not a simple tree, but a graph with possibly many 
cycles. As a matter of fact, very often child nodes have pointers 
to parent nodes, so that what is logically a tree is practically 
a graph with lots of cycles. So it is not possible to identify a 
root object which does not have incoming dead pointers, and no 
guarantee can be provided.

Array operation with overlapping

[Oleg Gorbunov via Digitalmars-d]

I am new in D, but saw some strage behavour.

Overlapping is detected for + and * array operation, but not for 
- and /.



import std.stdio;

void main()
{
int[] slice = [2, 2, 2, 2];
int[] slice2 = slice[0 .. $ - 1];
int[] slice3 = slice[1 .. $];

writeln("slice  before: ", slice);
writeln("slice2 before: ", slice2);
writeln("slice3 before: ", slice3);

const auto cmd = "slice3[] = slice2[] + slice3[];";

writeln( "cmd: ", cmd );

mixin( cmd );

writeln("slice  after : ", slice);
writeln("slice2 after : ", slice2);
writeln("slice3 after : ", slice3);
}

When this code is run at 'dlang.org'

slice  before: [2, 2, 2, 2]
slice2 before: [2, 2, 2]
slice3 before: [2, 2, 2]
cmd: slice3[] = slice2[] + slice3[];
object.Error@(0): Overlapping arrays in vector operation: 8 
byte(s) overlap of 12


??:? nothrow @safe void 
rt.util.array._enforceNoOverlap(const(char[]), ulong, ulong, 
const(ulong)) [0x44f7f3]

??:? _arraySliceSliceAddSliceAssign_i [0x44c1b6]
??:? _Dmain [0x4408bb]
??:? 
_D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv 
[0x44c8a6]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) [0x44c7f0]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).runAll() [0x44c862]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) [0x44c7f0]

??:? _d_run_main [0x44c761]
??:? main [0x44a389]
??:? __libc_start_main [0x40d80a14]



If change + to -

const auto cmd = "slice3[] = slice2[] - slice3[];";

When it is run at 'dlang.org'

slice  before: [2, 2, 2, 2]
slice2 before: [2, 2, 2]
slice3 before: [2, 2, 2]
cmd: slice3[] = slice2[] - slice3[];
slice  after : [2, 0, -2, -4]
slice2 after : [2, 0, -2]
slice3 after : [0, -2, -4]