Re: core.sys.posix.setjmp unavailable for OS X?

[H. S. Teoh via Digitalmars-d-learn]

On Tue, Jan 16, 2018 at 08:29:57AM +0100, Jacob Carlborg via 
Digitalmars-d-learn wrote:
> On 2018-01-16 08:29, Jacob Carlborg wrote:
> 
> > They're used to implement Objective-C exceptions on macOS 32bit and
> > iOS.
> 
> Forgot the second part:
> 
> ... so I assume that means it works.
[...]

So we should add that to druntime, then.


T

-- 
MSDOS = MicroSoft's Denial Of Service

Re: core.sys.posix.setjmp unavailable for OS X?

[Jacob Carlborg via Digitalmars-d-learn]

On 2018-01-16 08:29, Jacob Carlborg wrote:


They're used to implement Objective-C exceptions on macOS 32bit and iOS.


Forgot the second part:

... so I assume that means it works.

--
/Jacob Carlborg

Re: core.sys.posix.setjmp unavailable for OS X?

[Jacob Carlborg via Digitalmars-d-learn]

On 2018-01-15 20:37, H. S. Teoh wrote:


It's probably just a matter of adding the appropriate prototypes /
declarations to druntime. Provided that they actually work as
advertised, of course.


They're used to implement Objective-C exceptions on macOS 32bit and iOS.

--
/Jacob Carlborg

[Issue 16017] package functions show up in std.experimental.allocator.common docs

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16017

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

https://github.com/dlang/phobos/commit/639c07e9428df844bb21adb8007503aa1e33b9b2
Fix Issue 16017 - package functions show up in
std.experimental.allocator.common docs

https://github.com/dlang/phobos/commit/d10a9da36b273c57308b52b92ca7a6aefe9b37f0
Merge pull request #6005 from wilzbach/fix-16017

--

[Issue 17440] Nullable.nullify() resets referenced object

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17440

--- Comment #12 from hst...@quickfur.ath.cx ---
I think you misunderstood my comment.  I meant that one way to fix this bug is
to change Nullable, or at least the overload that takes a single type
parameter, so that it does not instantiate for reference types, or redirects
the instantiation to Nullable!(T, null), so that when you call .nullify on it,
it will just set the reference to null instead of attempting to destroy the
object by calling .destroy on it.

It really does not make sense to use Nullable!T, as currently implemented, for
a class type T, since making that means there will be *two* null states, one
with .nullify / .isNull, and the other with `= null` and `is null`, and the two
null states will not be equivalent. That will only lead to more confusion.  The
fact that Nullable!T's dtor calls .destroy is further proof that the original
intent was to use it with by-value types, not with class references.  I'd say
either the docs should recommend using Nullable!(T, null) for class types T, or
else Nullable!T in that case should just internally redirect to Nullable!(T,
null).

--

Re: [theory] What is a type?

[thedeemon via Digitalmars-d]

On Monday, 15 January 2018 at 20:46:19 UTC, Ali wrote:

If you want to learns the ins and outs of types, this books 
comes highly recommended


https://www.cis.upenn.edu/~bcpierce/tapl/


+1, TAPL is a must read for anyone in CS, I believe.
Also recommended: "Type Theory & Functional Programming" by Simon 
Thompson,

"Practical Foundations for Programming Languages" by Robert Harper
and his and his colleagues lectures here:
https://www.cs.uoregon.edu/research/summerschool/archives.html

Many programmers remain unaware that there is a discipline called 
Type Theory, as part of math in general, it predates all 
electronic computers and it's still very relevant today. Anyone 
dabbling into compilers and programming language theory should 
learn the basics of type theory, proof theory and some category 
theory, these three are very much connected and talk about 
basically the same constructions from different angles (see 
Curry-Howard correspondence and "computational trinitarianism"). 
It's ridiculous how many programmers only learn about types from 
books on C++ or MSDN, get very vague ideas about them and never 
learn any actual PLT. Of course type is not a set of values, or 
any other set, not at all.

Re: Beta 2.078.1

[Martin Nowak via Digitalmars-d-announce]

On 01/16/2018 06:59 AM, Martin Nowak wrote:
> Lots of useful fixes, most prominently dub now timeouts and uses one
> of the mirrors when code.dlang.org has connection issues.

https://github.com/dlang/dub/pull/1338

Beta 2.078.1

[Martin Nowak via Digitalmars-d-announce]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA512

First beta for the 2.078.1 patch release.

Lots of useful fixes, most prominently dub now timeouts and uses one
of the mirrors when code.dlang.org has connection issues.

http://dlang.org/download.html#dmd_beta
http://dlang.org/changelog/2.078.1.html

Please report any bugs at https://issues.dlang.org

- -Martin

-BEGIN PGP SIGNATURE-

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UNNLaOG3u5eXA8EUaUT1Tlj3vUM/DUq/MRRz9e1LHkmOQCsdxOM8ozlCoRe6cxky
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[Issue 18193] module config is in file 'rt/config.d' which cannot be read

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18193

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

https://github.com/dlang/druntime/commit/10afa6944bb3ac479cbcabc5499a86136907b95f
Fix issue 18193 - module config is in file 'rt/config.d' which cannot be read
(edit)

https://github.com/dlang/druntime/commit/105d4a5ca279316665b3b796bf5ca7d249595caf
Add test to the bug 18193

--

[Issue 13742] undefined reference to __coverage

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13742

--- Comment #8 from github-bugzi...@puremagic.com ---
Commits pushed to master at https://github.com/dlang/dmd

https://github.com/dlang/dmd/commit/69e7bd18892df18f682906916bf8c8ad87fb30e5
fix Issue 13742 - undefined reference to __coverage

- Nested template functions may reference coverage symbols of other modules.
  Those coverage symbols are either still `null` or already `symbol_reset`, in
  the former case coverage instrumentation is silently skipped, in the later
  case the linker will cause an error. This is because the current object file
  ends up with two `__coverage` symbols, one local BSS symbols and an undefined
  external symbol (for the other module's coverage).

- Fixed by mangling the symbols as _D3pkg3mod__coverageZ (similar to
  __ModuleInfoZ) and making them global.

- Ideally the symbols would use -visibility=hidden, but that ELF backend
feature
  isn't yet accessible from glue.d.

- This does not fix missing coverage when the referenced module hasn't yet
  been codegen'ed (e.g. because it follows on the command line or is part of
  another separate compilation). Using weak linkage to make this heuristically
  work would incurr some overhead for the coverage instrumentation.
  Unconditionally referencing coverage info OTOH might be too excessive,
  e.g. when the template function is in phobos, which would require to
recompile
  phobos with -cov for successful linking.

https://github.com/dlang/dmd/commit/0cb16110c307b608034d49289e2a650e7d7d7dd8
Merge pull request #7654 from MartinNowak/fix13742

fix Issue 13742 - undefined reference to __coverage

--

[Issue 13742] undefined reference to __coverage

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13742

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

   What|Removed |Added

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

--

[Issue 18233] building with -m64 doesn't work with sc.ini from the zip distribution and VS2017

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18233

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

https://github.com/dlang/dmd/commit/e9b2864e1b0f59415045533423c64447b3e468aa
fix issue 18233 - building with -m64 doesn't work with sc.ini from the zip
distribution and VS2017

https://github.com/dlang/dmd/commit/a81d286dd69dafb6d8c2605804602b19e98634dd
Merge pull request #7686 from rainers/cleanup_ini

--

[Issue 18111] unittests get different names depending on how the files are passed to dmd

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18111

--- Comment #2 from github-bugzi...@puremagic.com ---
Commits pushed to master at https://github.com/dlang/dmd

https://github.com/dlang/dmd/commit/3b551d3ce6d9d654ba64c11ce0c7c926b1197aa0
Fix issue 18111: use fully qualified name for modules in unittest names

https://github.com/dlang/dmd/commit/e6038789f09d629bc2401569be88689dee665e3f
Merge pull request #7496 from atilaneves/fix_issue_18111

--

Re: I want to transmit the class name and the member name in the method

[Martin Nowak via Digitalmars-d-learn]

On Monday, 15 January 2018 at 15:28:19 UTC, Martin Nowak wrote:
More concise stuff is possible with heavy compile-time trickery 
(https://dpaste.dzfl.pl/cd375ac594cf) without incurring dreaded 
1+N queries or even any unnecessary SELECT fields.


foreach (u; db.select!User.where!"NOT can_overdraw")
{
sendMail(u.name, u.mail.addr, u.lendings // no 1+N here
.where!"DATEDIFF(NOW(), end_date) >= 7 AND book.amount 
< 20")

.map!(l => l.book.Reminder)); // client side range API
}

This has become even more of a challenge since we plan to make 
it a @safe @nogc poster child.


If anyone wants to help with this project please contact me.

At the moment reworked @safe @nogc database drivers would be 
most helpful.

I'll soon publish a small RC, Uniq, Weak library.
Unbuffered IO foundations are already here 
https://github.com/MartinNowak/io, but not yet practically 
proven, and still lacking vibe-core scheduler/eventcore 
integration.


If someone wants to see this happen, but doesn't have enough time 
to contribute,
you could help to crowdfund this work, so I could afford to spent 
more time working on this.


Get in contact with us for more details.
https://dlang.org/donate.html

Re: Does it have an http2 server/client lib like in golang?

[Martin Nowak via Digitalmars-d-learn]

On Monday, 15 January 2018 at 18:07:24 UTC, Cergoo wrote:

subj


WIP but a bit stalled.
https://github.com/vibe-d/vibe.d/tree/http2-botan-cleanup

Unless you really need server-push of assets, HTTP/2 on a reverse 
proxy gets you the same performance benefits as well.

[Issue 17440] Nullable.nullify() resets referenced object

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17440

--- Comment #11 from Marenz  ---
I can only repeat what I said before. The principle of the least surprise
should apply. No one expects their object to be destroyed when a reference to
it is set to null, be it through .nullify(); or through = null;
It's not difficult to fix and it saves lots of people debugging time, figuring
out why the hell their object is gone.

Note that already two persons have stumbled over this AND have reported it. God
knows how many more this happened to who haven't given this valuable feedback.

--

class initialization

[Marc via Digitalmars-d-learn]

in C# you can initilizate the class members like this:


var foo = new Foo { a = 1, b = 2 };


I found something similar to structs in D:


myStruct S = {a:1, b:2};


But can't figure out if D does have that for classes.

[Issue 18242] DMD Segmentation fault.

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18242

--- Comment #1 from changlon  ---


/**
 * This code is based on Adam D. Ruppe $(LINK2
http://arsdnet.net/dcode/minimal.zip minimal.zip).
 * Probably Boost licensed
 */
module object;


/// All D class objects inherit from Object.
class Object {
}

/// The base class of all thrown objects.
class Throwable {

}


int _d_run_main() {
int result = void;
try result = 1;
catch(Throwable e) _d_print_throwable;
}


==
dmd -defaultlib= -debuglib=  object.d

--

Re: Undefined Reference to OpenSSL EVP functions

[Chris via Digitalmars-d-learn]

On Tuesday, 16 January 2018 at 00:52:09 UTC, Chris wrote:
I am trying to hook up OpenSSL to a dlang project I'm working 
on, but I have hit a problem when trying to link.


I currently get the following linking error:


undefined reference to `EVP_CIPHER_CTX_init'


I have made sure to include the module wrapping the c headers


import deimos.openssl.evp;


And I have made sure that I am linking to "libcrypto" and 
"libssl" in my "dub.json" file. I have even pointed the linker 
to my "/usr/lib" folder


And I made sure that those libraries are installed on my system 
in "/usr/lib"



libcrypto.o
libssl.o


Here is the code that I am trying to run:


import deimos.openssl.evp

void main()
{
   EVP_CIPHER_CTX *ctx;
   EVP_CIPHER_CTX_init(ctx);
}


Here is the full verbose output of dub: 
https://pastebin.com/raw/4FnhCyr2


Here is my full dub.json file: https://pastebin.com/raw/1Z3WGBET

Any help would be greatly appreciated! Thank you so much!


Hi Everyone, this is not an error in D, or the OpenSSL wrapper 
code it's just me not reading the OpenSSL man pages...


EVP_CIPHER_CTX_init is not longer the way to create the context 
in 1.1.0 - It has been replaced by:



EVP_CIPHER_CTX *ctx;
ctx = EVP_CIPHER_CTX_new()


RTFM...

Trait compiles

[Jiyan via Digitalmars-d-learn]

Hello,
is there anyway to do something like this:

mixin template foo( exp)
{
static if(__traits(compiles, exp))exp;
}

Thanks :)

[Issue 18242] New: DMD Segmentation fault.

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18242

  Issue ID: 18242
   Summary: DMD Segmentation fault.
   Product: D
   Version: D2
  Hardware: All
OS: All
Status: NEW
  Severity: blocker
  Priority: P1
 Component: dmd
  Assignee: nob...@puremagic.com
  Reporter: chang...@gmail.com

I run into DMD segmentation fault under linux and Mac OSX, not test windows
yet.


DMD v2.078.0-401-g716303a41-dirty DEBUG

Program received signal SIGSEGV, Segmentation fault.
0x558c694e in
_D3dmd12statementsem13catchSemanticFCQBj9statement5CatchPSQCe6dscope5ScopeZv
(sc=0x75f611e0, 
c=0x77efb550) at dmd/statementsem.d:4038
4038 cd != ClassDeclaration.exception &&
!ClassDeclaration.exception.isBaseOf(cd, null) &&


The demangle symbol is: void
dmd.statementsem.catchSemantic(dmd.statement.Catch, dmd.dscope.Scope*) 


The code is rather big and I can not made it work with dustmite.

--

Re: TSV Utilities release with LTO and PGO enabled

[Jon Degenhardt via Digitalmars-d-announce]

On Tuesday, 16 January 2018 at 00:19:24 UTC, Martin Nowak wrote:
On Sunday, 14 January 2018 at 23:18:42 UTC, Jon Degenhardt 
wrote:
Combined, LTO and PGO resulted in performance improvements 
greater than 25% on three of my standard six benchmarks, and 
five of the six improved at least 8%.


Yay, I'm usually seeing double digit improvements for PGO 
alone, and single digit improvements for LTO. Meaning PGO has 
more effect even though LTO seems to be the more hyped one.

Have you bothered benchmarking them separately?


Last spring I made a few quick tests of both separately. That was 
just against the app code, without druntime/phobos. Saw some 
benefit from LTO, mainly one of the tools, and not much from PGO.


More recently I tried LTO standalone and LTO plus PGO, both 
against app code and druntime/phobos, but not PGO standalone. The 
LTO benchmarks are here: 
https://github.com/eBay/tsv-utils-dlang/blob/master/docs/dlang-meetup-14dec2017.pdf. I've haven't published the LTO + PGO benchmarks.


The takeaway from my tests is that LTO and PGO will benefit 
different apps differently, perhaps in ways not easily predicted. 
One of my tools benefited primarily from PGO, two primarily from 
LTO, and one materially from both. So, it is worth trying both.


For both, the big win was from optimizing across app code and 
libs (druntime/phobos in my case). It'd be interesting to see if 
other apps see similar behavior, either with phobos/druntime or 
other libraries, perhaps libraries from dub dependencies.

Re: Phobos bindings

[Steven Schveighoffer via Digitalmars-d]

On 1/14/18 1:17 PM, Temtaime wrote:

Phobos comes with zlib, curl and sqlite bindings.
Zlib sources come with phobos, so there's no need to build and link with 
it separately.

Why there's no curl and sqlite sources ?

For example sqlite comes as 1 file. I think we can add it too, isn't it ?


The inclusion of etc in general has been considered a mistake. Since 
they were added, dub has obviated any need to include such things in 
Phobos. In fact there have been efforts to remove them from Phobos 
(https://github.com/dlang/phobos/pull/4283).


That being said, zlib is quite a static library. The others are actively 
developed, and we shouldn't need to keep updating all our sources when 
the external dependencies change.


-Steve

Undefined Reference to OpenSSL EVP functions

[Chris via Digitalmars-d-learn]

I am trying to hook up OpenSSL to a dlang project I'm working on, 
but I have hit a problem when trying to link.


I currently get the following linking error:


undefined reference to `EVP_CIPHER_CTX_init'


I have made sure to include the module wrapping the c headers


import deimos.openssl.evp;


And I have made sure that I am linking to "libcrypto" and 
"libssl" in my "dub.json" file. I have even pointed the linker to 
my "/usr/lib" folder


And I made sure that those libraries are installed on my system 
in "/usr/lib"



libcrypto.o
libssl.o


Here is the code that I am trying to run:


import deimos.openssl.evp

void main()
{
   EVP_CIPHER_CTX *ctx;
   EVP_CIPHER_CTX_init(ctx);
}


Here is the full verbose output of dub: 
https://pastebin.com/raw/4FnhCyr2


Here is my full dub.json file: https://pastebin.com/raw/1Z3WGBET

Any help would be greatly appreciated! Thank you so much!

Re: Proposed Phobos equivalent of wcswidth()

[WhatMeForget via Digitalmars-d]

On Monday, 15 January 2018 at 13:34:09 UTC, Jack Stouffer wrote:

On Saturday, 13 January 2018 at 17:26:52 UTC, H. S. Teoh wrote:

...


Thanks for taking the time to do this.

And now the obligatory bikeshed: what should the Phobos 
equivalent of wcswidth be called?


std.utf.displayWidth


std.utf.bikeshed

Never heard that phrase before. Nice one :)

Re: TSV Utilities release with LTO and PGO enabled

[Martin Nowak via Digitalmars-d-announce]

On Sunday, 14 January 2018 at 23:18:42 UTC, Jon Degenhardt wrote:
Combined, LTO and PGO resulted in performance improvements 
greater than 25% on three of my standard six benchmarks, and 
five of the six improved at least 8%.


Yay, I'm usually seeing double digit improvements for PGO alone, 
and single digit improvements for LTO. Meaning PGO has more 
effect even though LTO seems to be the more hyped one.

Have you bothered benchmarking them separately?

[Issue 18241] Missing characters from std.uni.unicode.Default_Ignorable_Code_Point

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18241

hst...@quickfur.ath.cx changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |INVALID

--- Comment #2 from hst...@quickfur.ath.cx ---
Actually, nevermind this bug. The file at
http://www.unicode.org/L2/L2002/02368-default-ignorable.pdf is outdated;
std.uni actually does obey the latest standard as given in
ftp://ftp.unicode.org/Public/UNIDATA/DerivedCoreProperties.txt.

--

Re: How to run vibe.d web app in XAMPP server ?

[singingbush via Digitalmars-d]

On Monday, 15 January 2018 at 06:22:13 UTC, Jayam wrote:
In our production server, we have only XAMPP for use to deploy 
web app and mysql combinedly?

Is there any way how to deploy the vibe.d web app into XAMPP ?


To use Apache to proxy requests to your D app do something along 
these lines:


Configure a Virtual Host for use with the application:

sudo vim /etc/apache2/sites-available/yoursite.conf

using the following content:

ServerAdmin webmas...@example.com
ServerName example.com
ServerAlias www.example.com

ErrorLog /var/log/apache2/yoursite-error.log
CustomLog /var/log/apache2/yoursite-access.log common

ProxyRequests off
ProxyPreserveHost off
ProxyPass / http://127.0.0.1:8080
ProxyPassReverse / http://127.0.0.1:8080



Then make sure to enable the relevant mods and your site

sudo a2enmod proxy proxy_http
sudo a2ensite yoursite

Verfiy the Apache config with apachectl configtest then restart:

sudo systemctl restart apache2

[Issue 18241] Missing characters from std.uni.unicode.Default_Ignorable_Code_Point

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18241

--- Comment #1 from hst...@quickfur.ath.cx ---
Actually, strike U+06DD and U+070F from the list. These are explicitly
specified by TR 44 as being exceptional cases that should NOT be ignored, even
though they belong to the Cf category.

--

[Issue 18241] New: Missing characters from std.uni.unicode.Default_Ignorable_Code_Point

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18241

  Issue ID: 18241
   Summary: Missing characters from
std.uni.unicode.Default_Ignorable_Code_Point
   Product: D
   Version: D2
  Hardware: x86_64
OS: Linux
Status: NEW
  Severity: normal
  Priority: P1
 Component: phobos
  Assignee: nob...@puremagic.com
  Reporter: hst...@quickfur.ath.cx

The set returned by unicode.Default_Ignorable_Code_Point is missing some
characters listed in:

http://www.unicode.org/L2/L2002/02368-default-ignorable.pdf

where Default_Ignorable_Code_Point is defined as:

Other_Default_Ignorable_Code_Point + (Cf + Cc + Cs - White_Space)

While characters in Other_Default_Ignorable_Code_Point seem to be included
correctly, two characters in Cf appear to be missing from the set:

- U+06DD
- U+070F

Furthermore, characters in (Cc - White_Space) are also missing:

- U+ to U+0008
- U+000E to U+001F


(See also: PR #5, referencing the Unicode Standard section 5.22.)


Not sure if this is because these missing characters were added in a later
Unicode standard than was originally implemented in std.uni.

--

Re: Tuple DIP - tuple unification with arrays and structs

[Walter Bright via Digitalmars-d]

On 1/14/2018 6:55 AM, Q. Schroll wrote:

How is (1, 2) different from [1, 2] (static array)?

It's a very good question. It's corollary is how is (1, 2) different from

   struct S { int a, b; }

It does turn out that int[2] is structurally (!) the same as struct S. This is a 
property I've taken some pains to ensure stays valid, and it has turned out to 
be nicely useful.


But consider:

   S foo(char a, char b);

   t = ('a', 'b');
   foo(t);  // equivalent to foo('a', 'b')

That works. But:

   S s = {'a', 'b' };
   foo(s);  // Does not work

It does not work is because s as a parameter has a distinctly different ABI than 
(char, char). The former consumes an int sized parameter, the latter two int 
sized parameters. A similar issue exists with the return value.


So far, the issue of unification of tuples with arrays (and structs) has 
defeated me because of the fundamental structural differences in the ABI which 
we are stuck with.

Re: Tuple DIP

[Walter Bright via Digitalmars-d]

On 1/14/2018 10:17 AM, Timon Gehr wrote:
It's inherited from C, where all struct instances have size at least 1. (Such 
that each of them has a distinct address.)


There are some peculiarities with that, like with multiple inheritance sometimes 
the size really is zero :-)

Re: run.dlang.io can now display ASM + AST + IR

[kinke via Digitalmars-d-announce]

On Sunday, 14 January 2018 at 04:18:41 UTC, Seb wrote:

3) IR (LDC only)

https://run.dlang.io/is/BOTNDf


Thanks Seb. I particularly like this feature. After a quick 
glance, the debuginfos (-g) seem to be needlessly enforced, 
bloating the IR.
A colored output would be a nice improvement; there's a plugin 
for the google-code-prettify JS library [1], which wouldn't 
increase the server load. Maybe there's one for asm too.


[1] https://gist.github.com/ndabas/2850418

Re: How to imporve D-translation of these Python list comprehensions ?

[Timon Gehr via Digitalmars-d-learn]

On 15.01.2018 20:05, xenon325 wrote:



I think, most clear code would be with tripple `foreach`, so I'll go 
with that. But probably someone will come up with something better and 
range-ier.


Suggestion are welcome!


import std.stdio, std.algorithm, std.range, std.array, std.conv, 
std.json, std.typecons;


auto aa(R)(R r){
typeof(r.front[1])[typeof(r.front[0])] a;
foreach(x;r) a[x[0]] = x[1];
return a;
}
alias emap(alias a) = map!(x => a(x.expand));

void main(){
auto srv1 = [
"acs": ["ver": "1.2.3", "rev": "6f2260d"],
"cms": ["ver": "4.5", "rev": "b17a67e"],
"ots": ["ver": "6.7.80", "rev": "4f487d2"]];
auto srv2 = [
"acs": ["ver": "1.2.3", "rev": "6f2260d"],
"cms": ["ver": "5.1", "rev": "2a56c53"],
"vaa": ["ver":"0.7", "rev": "00852cb"]];

chain(srv1.keys, srv2.keys).sort.uniq
.map!(k => chain(only(tuple("_name", k)),
 cartesianProduct(only("ver", "rev"), 
only(srv1, srv2).enumerate)
 .emap!((prop, srv) => tuple(text(prop, 
srv.index), srv.value.get(k, null).get(prop, "")))

  ).aa).array.JSONValue.toPrettyString.writeln;
}

Re: How to imporve D-translation of these Python list comprehensions ?

[Timon Gehr via Digitalmars-d-learn]

On 15.01.2018 22:51, Timon Gehr wrote:

auto aa(R)(R r){
     typeof(r.front[1])[typeof(r.front[0])] a;
     foreach(x;r) a[x[0]] = x[1];
     return a;
}


Actually, better to use std.array.assocArray.

import std.stdio, std.algorithm, std.range, std.array, std.conv, 
std.json, std.typecons;

alias emap(alias a) = map!(x => a(x.expand));

void main(){
auto srv1 = [
"acs": ["ver": "1.2.3", "rev": "6f2260d"],
"cms": ["ver": "4.5", "rev": "b17a67e"],
"ots": ["ver": "6.7.80", "rev": "4f487d2"]];
auto srv2 = [
"acs": ["ver": "1.2.3", "rev": "6f2260d"],
"cms": ["ver": "5.1", "rev": "2a56c53"],
"vaa": ["ver": "0.7", "rev": "00852cb"]];

chain(srv1.keys, srv2.keys).sort.uniq
.map!(k => chain(only(tuple("_name", k)),
 cartesianProduct(only("ver", "rev"), 
only(srv1, srv2).enumerate)
 .emap!((prop, srv) => tuple(text(prop, 
srv.index), srv.value.get(k, null).get(prop, "")))

  ).assocArray).array.JSONValue.toPrettyString.writeln;
}

Re: How to imporve D-translation of these Python list comprehensions ?

[Biotronic via Digitalmars-d-learn]

On Monday, 15 January 2018 at 19:05:52 UTC, xenon325 wrote:
I think, most clear code would be with tripple `foreach`, so 
I'll go with that. But probably someone will come up with 
something better and range-ier.


I will admit clarity has suffered, but I like the brevity:

import std.json : JSONValue;
import std.array : array, assocArray;
import std.range : enumerate, byPair;
import std.algorithm : sort, joiner, map, uniq, each;
import std.typecons : tuple;
import std.conv : to;
import std.stdio : writeln;

unittest {
immutable srv1 = ["acs": ["ver": "1.2.3", "rev": "6f2260d"], 
"cms": ["ver": "4.5", "rev": "b17a67e"], "ots": ["ver": "6.7.80", 
"rev": "4f487d2"]];
immutable srv2 = ["acs": ["ver": "1.2.3", "rev": "6f2260d"], 
"cms": ["ver": "5.1", "rev": "2a56c53"], "vaa": ["ver":"0.7", 
"rev": "00852cb"]];

immutable keys = ["rev", "ver"];
immutable srvs = [srv1, srv2];

alias aget = (name, key) => srvs.map!(s => s.get(name, 
[key:""])[key]);
alias bget = (name, key) => aget(name, key).enumerate.map!(b 
=> tuple(key~b.index.to!string, b.value));
alias merge = (aa1, aa2) => (aa2.byPair.each!(kv => 
aa1[kv.key] = kv.value), aa1);


auto result = srvs
.map!(s => s.byKey)
.joiner
.array
.sort
.uniq
.map!(name => merge(keys.map!(key => bget(name, 
key)).joiner.assocArray, ["_name": name]))

.array;

writeln(JSONValue(result).toPrettyString());
}

--
  Simen

Re: Article: Fuzzing D code with LDC

[H. S. Teoh via Digitalmars-d-announce]

On Sat, Jan 13, 2018 at 11:59:52PM +, Johan Engelen via 
Digitalmars-d-announce wrote:
> It's been a work-in-progress for half a year, but finished now:
> 
> http://johanengelen.github.io/ldc/2018/01/14/Fuzzing-with-LDC.html
[...]

It would be good to program custom fuzzers for Phobos modules,
especially the ones with generic code like std.algorithm and std.range,
a lot of which I suspect have unhandled edge cases and other such
overlooked flaws.  Fuzzing at this level will be harder than merely
fuzzing with random data; as input we'd need higher-level objects like
ranges of various types and by-reference / by-value semantics.  And
detecting problem cases may not be so easy (how to detect if, say,
reduce() returned the wrong answer when the input is randomized?).


T

-- 
Beware of bugs in the above code; I have only proved it correct, not tried it. 
-- Donald Knuth

[Issue 18240] core.stdc.wchar_ wmemset, etc. should be pure

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18240

--- Comment #1 from github-bugzi...@puremagic.com ---
Commits pushed to master at https://github.com/dlang/druntime

https://github.com/dlang/druntime/commit/2bc68a917905faa89eb9b6458dc52b0cdf992ea4
Fix Issue 18240 - core.stdc.wchar_ wmemset, etc. should be pure

Also regularize qualifiers to match core.stdc.string.

https://github.com/dlang/druntime/commit/c5b2777dd05b676c001677a808a60d352d43e6a2
Merge pull request #2043 from n8sh/wmemset-pure

Fix Issue 18240 - core.stdc.wchar_ wmemset, etc. should be pure
merged-on-behalf-of: Iain Buclaw 

--

[Issue 17440] Nullable.nullify() resets referenced object

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17440

--- Comment #10 from hst...@quickfur.ath.cx ---
P.S. Actually, Nullable does have another overload that takes a null value to
be used in lieu of a boolean flag.  So conceivably, you could use Nullable!(T,
null) instead of Nullable!T and you will have the requisite semantics.

--

Re: How to imporve D-translation of these Python list comprehensions ?

[lobo via Digitalmars-d-learn]

On Monday, 15 January 2018 at 19:05:52 UTC, xenon325 wrote:
A workmate has recently shown this piece of code to show how 
nice Python is (we are mostly C and growing C++ shop):


[...]


Well if that is what they can do in Python I'd hate to see their 
C++! They have done a great job making Python code read like 
Perl. This looks like something you'd see in an assignment at 
uni; "Decipher this Python code and port to your language of 
choice" :)

Re: [theory] What is a type?

[Ola Fosheim Grøstad via Digitalmars-d]

On Monday, 15 January 2018 at 19:25:16 UTC, H. S. Teoh wrote:
At the most abstract level, a type is just a set. The members 
of the set represent what values that type can have.


Hm, yes, like representing an ordered pair (a,b) as {{a},{a,b}}.

But I think typing is more commonly viewed as a filter. So if you 
represent all values as sets, then the type would be a filter 
preventing certain combinations.


It is a matter of perspective, constructive or not constructive. 
Kinda like synthesis, additive (combine sines) or subtractive 
(filter noise).

Re: [theory] What is a type?

[Ali via Digitalmars-d]

On Sunday, 10 October 2010 at 12:28:32 UTC, Justin Johansson 
wrote:

Now having hopefully described that a type is something
that might well have multiple orthogonal aspects to its
identity, how would one go about implementing a dynamic
language with such a complex type system in D?

I realize that this is a complex topic and that it might
require better articulation than so far I have given.

Nevertheless, thanks for all replies,
Justin Johansson


If you want to learns the ins and outs of types, this books comes 
highly recommended


https://www.cis.upenn.edu/~bcpierce/tapl/

Re: [theory] What is a type?

[Mark via Digitalmars-d]

On Sunday, 10 October 2010 at 12:28:32 UTC, Justin Johansson 
wrote:

Specifically I have a problem in trying to implement
a functional language translator in D.  My target language
has a rather non-conventional type system, in which,
superficially at least, types can be described as being
Cartesian in nature. That is,
types in this system have two orthogonal dimensions:
(1) classical data-type (e.g. boolean, number, string,
object) and
(2) Kleene cardinality (occurrences) with respect to (1).

The axial origin of this Cartesian type-system correlates well
with the concept of the "top" type (AKA "Unit" in Scala)
and as the rather adhoc "void" type in many Algol-derived
languages such as C/C++/Java/D.

So along axis 1 we might broadly describe the classical
data types as item, boolean, number, string, object where
item is effectively either a superclass or variant of the
other mentioned types.

Along axis 2 we describe Kleene occurrences of 1 as may be
passed contractually to a receiving function.  These
occurrences may be enumerated six-fold as:
zeroOrMore
zeroOrOne
oneOrMore
exactlyZero
exactlyOne
none

Readers may see that, for example, zeroOrOne is a special
case (perhaps a subclass?) of zeroOrMore.  exactlyOne is
a special case of both zeroOrOne and oneOrMore (sounds like
multiple inheritance?).  OTOH, exactlyZero is a special
case of zeroOrOne, which, in turn, is a special case of
zeroOrmore.

none is a special case of all of the above and reflects
the cardinality facet of the return type of a function
that never returns (say as by throwing an exception).

To make this type system even more enigmatic lets add a
third dimension, taking the 2-D Cartesian type system
model to a 3-D Spatial model, by imagining a further
degree of freedom with respect to laziness of evaluation
(AKA closure of arguments).

Now having hopefully described that a type is something
that might well have multiple orthogonal aspects to its
identity, how would one go about implementing a dynamic
language with such a complex type system in D?

I realize that this is a complex topic and that it might
require better articulation than so far I have given.

Nevertheless, thanks for all replies,
Justin Johansson


Well, in D-speak you could imagine taking (perhaps arbitrarily) 
the first axis (basic data type) as the "skeleton" and attach 
various properties to it. For example:


Int!(exactlyOne, eager) x = 42;
Int!(zeroOrMore, lazy) y;
readf("%d", );
auto foo = x+y; // What does this mean? What type is foo?

You seem to have in mind a syntax for your type system but I'm 
not sure how you intend for the semantics to work. D's templates 
are really nice in that they allow you to express many properties 
of a term that are not "hard coded" into its type. So you can do 
stuff like:


enum MinimizationTarget { programThroughput, GCThroughput, 
heapOverhead, pauseTimes, pauseFrequency, heapFragmentation, 
warmupTime }

auto GarbageCollector(MinimizationTarget[] priorities = [])()
{
static if (priorities == []) return 
StopTheWorldMarkAndSweepGC();
else static if (priorities[0] == heapFragmentation) return 
copyingGC();
else static if (/* some boolean algebra condition on 
$priorities */) return GenerationalMarkAndSweepGC();

else /* etc. */
}
auto myGC = GarbageCollector![pauseTimes, heapOverHead, 
programThroughput];

auto myGraph = Graph!(myGC, directed);

which is pretty cool. :)

Re: How to imporve D-translation of these Python list comprehensions ?

[Igor Shirkalin via Digitalmars-d-learn]

On Monday, 15 January 2018 at 19:05:52 UTC, xenon325 wrote:
A workmate has recently shown this piece of code to show how 
nice Python is (we are mostly C and growing C++ shop):
dd = [dict(_name=k, **{a + str(i): aget(d, k, a) for a in 
aa for i, d in enumerate([srv1, srv2])}) for k in sorted(kk)]


This is the most terrible Python code I have ever seen.
If you know Python, could you please unroll to more readable form?


Suggestion are welcome!




---
Alexander

[Issue 17440] Nullable.nullify() resets referenced object

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17440

hst...@quickfur.ath.cx changed:

   What|Removed |Added

 CC||hst...@quickfur.ath.cx

--- Comment #9 from hst...@quickfur.ath.cx ---
But by-reference objects in D *already* have nullable semantics, i.e.:

---
class C {}
C c;
assert(c is null); // c is null by default
c = new C;
assert(c !is null);
c = null; // nullify
assert(c is null);
---

Of course the syntax is slightly different (direct use of null vs. .isNull /
.nullify).  But there's really no benefit to using Nullable with reference
types in D.

OTOH, if you're using generic code that expect a single API for nullable
objects, perhaps the solution is to write an overload of Nullable that simply
maps .isNull to `is null` and .nullify to `= null` when the wrapped type is a
class.

--

Re: Proposed Phobos equivalent of wcswidth()

[H. S. Teoh via Digitalmars-d]

On Sat, Jan 13, 2018 at 09:26:52AM -0800, H. S. Teoh via Digitalmars-d wrote:
[...]
>   https://github.com/quickfur/strwidth
[...]

One thing I'm seeking help with, and this is mainly directed at Dmitry
Olshansky but can be anyone here who knows the internal workings of
std.uni well enough, is how to transform the Trie generated by the
static ctor into compile-time TrieNode declarations.  This is one
blocker for my turning this code into a Phobos PR, because I don't want
to incur the cost of initializing this trie at runtime.

Also, on a related note, there exist nicer interfaces in std.uni for
constructing Tries that map ranges of codepoints to non-boolean values,
but none of these are available publicly.  The current implementation in
strwidth only uses the public API of std.uni, so the construction of the
trie is pretty horrendous (looping over individual codepoints and
creating an AA of individual codepoints -- including very large ranges
like the entire Unicode plane 2).  I wonder if some of these facilities
should be made public so that user code that needs to construct
codepoint tries that include large ranges of codepoints can do so more
efficiently.


T

-- 
This sentence is false.

Re: [theory] What is a type?

[Jonathan Marler via Digitalmars-d]

On Monday, 15 January 2018 at 19:34:23 UTC, Ali Çehreli wrote:


On 01/15/2018 10:58 AM, Jonathan Marler wrote:
> On Sunday, 10 October 2010 at 12:28:32 UTC, Justin Johansson
wrote:

> I'm getting "nostalgia" from all the math terminology :)

Just the date of the post you're responding to is sufficient 
for "nostalgia". ;)


Ali


Oh wow!  I don't know why the form post was on the first page of 
my form thread. You think he still checks his thread every day to 
see if someone has responded?  :)

Re: mysql-native: Prepared statements: Direction and future

[H. S. Teoh via Digitalmars-d-announce]

On Mon, Jan 15, 2018 at 01:30:42PM -0500, Nick Sabalausky (Abscissa) via 
Digitalmars-d-announce wrote:
> I've posted (what basically amounts to an article) about my current
> thoughts on addressing Prepared's current downsides in the next
> release (v2.0.0), as well as a little bit of future direction of the
> lib.
> 
> Anyone interested in mysql-native's prepared statements (especially
> their interplay with connection pools) is encouraged to take a look
> and share any thoughts:
> 
> https://github.com/mysql-d/mysql-native/issues/95#issuecomment-357757013

A lot of what you discuss here is pertinent not only to mysql-native,
but to (SQL) database bindings in general.  I've been facing much the
same questions in my own SQLite bindings, which are based on Adam
Ruppe's sqlite.d.

One of these days, we should draft up a "standard" API for SQL database
bindings in D, so that implementations can benefit from a well thought
out API design instead of rolling their own each time.


T

-- 
"If you're arguing, you're losing." -- Mike Thomas

Re: core.sys.posix.setjmp unavailable for OS X?

[H. S. Teoh via Digitalmars-d-learn]

On Mon, Jan 15, 2018 at 07:06:42PM +, bpr via Digitalmars-d-learn wrote:
> Is there a reason that it's unavailable on OS X when it works fine on
> Linux?  The functions exist on OS X, and it's easy enough to compile C
> programs using setjmp there; but not D programs. I don't think I'm
> getting a betterC experience on the Mac.
[...]

It's probably just a matter of adding the appropriate prototypes /
declarations to druntime. Provided that they actually work as
advertised, of course. There may be incompatibilities that I'm not aware
of that would preclude it from being added to druntime.

In any case, if druntime doesn't provide the right declarations, you
*could* just declare them yourself with an extern(C). E.g.:

extern(C) int setjmp(jmp_buf env);
extern(C) void longjmp(jmp_buf env, int val);
...
jmp_buf buf;
int rc = setjmp(buf);
if (rc == 0) {
...
longjmp(buf, rc);
} else {
// handle error
}

You'll need to obtain your system's definition of jmp_buf, of course,
and translate it into D appropriately. You can find it in the usual
system include directories, like /usr/include or something along those
lines.  Most C structs can be copied verbatim into D and it would work.

(Note that you'll need to find the *exact* declaration used; especially
for structs, you may not be able to just use generic declarations given
by the Posix spec, because if your OS has additional fields for internal
use, you want to make sure those fields are declared properly, otherwise
the struct will have the wrong size and you may get problems at
runtime.)

Better yet, once you figure out how to do it, submit a PR against
druntime so that future users of your OS will benefit from it. ;-)


T

-- 
A program should be written to model the concepts of the task it performs 
rather than the physical world or a process because this maximizes the 
potential for it to be applied to tasks that are conceptually similar and, more 
important, to tasks that have not yet been conceived. -- Michael B. Allen

Re: [theory] What is a type?

[H. S. Teoh via Digitalmars-d]

On Mon, Jan 15, 2018 at 06:58:37PM +, Jonathan Marler via Digitalmars-d 
wrote:
[...]
> That being said, I don't think this model really get much closer to
> answering the original question, "what is a type?".
[...]

At the most abstract level, a type is just a set. The members of the set
represent what values that type can have. Operations on types are
therefore simply operations on sets, which lets us bring in the entire
mechanism of mathematical sets to elaborate upon the theory of types.

A boolean, for example, is simply a 2-membered set B = {true, false}. A
struct of two booleans is just the Cartesian product B x B. An array of
booleans is simply the Kleene closure of B, i.e., the union of all
Cartesian powers of B, usually denoted as B*.

This abstract view disregards how a type is actually implemented, and
merely considers its set of possible values.  Under this model, you
begin by describing the sets of possible values your program will work
with. Then when you're ready to implement it, you decide on some kind of
mapping to map the abstract sets to the physical types provided by the
hardware.


On a more practical level, the way I see a type is an *interpretation*
imposed upon a series of zero or more bytes (or, if you want to drill
down even deeper, bits).  The same binary values can represent different
types, depending on how you interpret them.  Under this model, you
proceed in the opposite direction: starting with an arbitrary sequence
of bytes, you recursively build up interpretations of it until you
arrive at the data structures that your program will operate on.


The abstract view is useful when you're working within your problem
domain: it allows you to phrase your algorithms and transformations
directly in terms of the objects and operations you wish to work on. But
it's not always so easy to map this abstract model onto the quirks of
the hardware you have to work with. It's easy to think of trivial
mappings, of course, but generally they will have pretty poor
performance because they don't take advantage of the properties of the
underlying hardware.  Finding an *efficient* mapping that doesn't also
break correctness can be quite challenging.

The practical view is useful when you're building things from ground up,
e.g., when you're building a compiler. It lets you build up types that
can take advantage of the underlying hardware's properties, and also
avoid or work around hardware quirks or weaknesses.  It also allows you
to reinterpret types creatively, that may allow you to achieve
interesting effects (e.g., the data bytes output by the compiler can be
reinterpreted as executable code by the CPU). However, types built up
this way may not map nicely into your problem domain, and that forces
your code to become convoluted in order to compensate for the impedance
mismatch between the two. Correctness may also be compromised if the
objects in your problem domain don't have a 1-to-1 fit with the hardware
types (e.g., your calculator program might operate on integers in the
mathematical sense of numbers that can be arbitrarily large, but the int
type provided by the hardware is modulo some power of 2; so when values
get too large, what your program thinks of as an integer no longer
matches what the hardware implements, resulting in overflow/underflow
bugs).

Finding the sweet spot that balances the two is non-trivial, and is the
subject of entire fields of research. :-D


T

-- 
The trouble with TCP jokes is that it's like hearing the same joke over and 
over.

Re: [theory] What is a type?

[Ali Çehreli via Digitalmars-d]

On 01/15/2018 10:58 AM, Jonathan Marler wrote:
> On Sunday, 10 October 2010 at 12:28:32 UTC, Justin Johansson wrote:

> I'm getting "nostalgia" from all the math terminology :)

Just the date of the post you're responding to is sufficient for 
"nostalgia". ;)


Ali

gRPC in D good idea for GSOC 2018?

[Ali Çehreli via Digitalmars-d]

I know a project where D could benefit from gRPC in D, which is not 
among the supported languages:


  https://grpc.io/docs/

Do you think gRPC support is worth adding to GSOC 2018 ideas?

  https://wiki.dlang.org/GSOC_2018_Ideas

Ali

[Issue 17462] Order of base interfaces affects compiler behavior

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17462

--- Comment #4 from Andrei Alexandrescu  ---
The following C++ equivalent does require the additional implementation
(uncomment code to get it to compile):


class Marker {};
class Foo { public: virtual void foo() = 0; };

class FooMarked : public Foo, public Marker {};
class MarkedFoo : public Marker, public Foo  {};

class Base : public Foo { virtual void foo() {} };

class Derived1 : public Base, public FooMarked {
//virtual void foo() {}
}; 
class Derived2 : public Base, public MarkedFoo {
//virtual void foo() {}
};

int main() {
auto d1 = new Derived1;
auto d2 = new Derived2;
}


However, this other code, which arguably is closer in spirit, does work:


class Marker {};
class Foo { public: virtual void foo() = 0; };

class FooMarked : virtual public Foo, public Marker {};
class MarkedFoo : public Marker, virtual public Foo  {};

class Base : virtual public Foo { virtual void foo() {} };

class Derived1 : public Base, public FooMarked {}; 
class Derived2 : public Base, public MarkedFoo {};

int main() {
auto d1 = new Derived1;
auto d2 = new Derived2;
}


--

core.sys.posix.setjmp unavailable for OS X?

[bpr via Digitalmars-d-learn]

Is there a reason that it's unavailable on OS X when it works 
fine on Linux? The functions exist on OS X, and it's easy enough 
to compile C programs using setjmp there; but not D programs. I 
don't think I'm getting a betterC experience on the Mac.


I'd also ask why the there are no D docs for core.sys.posix but I 
read the responses to the last time the question was asked and 
now I'm D-pressed. :-(

How to imporve D-translation of these Python list comprehensions ?

[xenon325 via Digitalmars-d-learn]

A workmate has recently shown this piece of code to show how nice 
Python is (we are mostly C and growing C++ shop):


import json
from itertools import chain

srv1 = {'acs': {'ver': '1.2.3', 'rev': '6f2260d'}, 'cms': 
{'ver': '4.5', 'rev': 'b17a67e'}, 'ots': {'ver': '6.7.80', 'rev': 
'4f487d2'}}
srv2 = {'acs': {'ver': '1.2.3', 'rev': '6f2260d'}, 'cms': 
{'ver': '5.1', 'rev': '2a56c53'}, 'vaa': {'ver':'0.7', 'rev': 
'00852cb'}}



def aget(d, k1, k2):
return d.get(k1, {}).get(k2, '')

aa = ['ver', 'rev']
kk = set(chain(srv1.keys(), srv2.keys()))
dd = [dict(_name=k, **{a + str(i): aget(d, k, a) for a in aa 
for i, d in enumerate([srv1, srv2])}) for k in sorted(kk)]


print(json.dumps(dd, indent=2, sort_keys=True))


Output is:

[
  {
"_name": "acs",
"rev0": "6f2260d",
"rev1": "6f2260d",
"ver0": "1.2.3",
"ver1": "1.2.3"
  },
  {
"_name": "cms",
"rev0": "b17a67e",
"rev1": "2a56c53",
"ver0": "4.5",
"ver1": "5.1"
  },
  {
"_name": "ots",
"rev0": "4f487d2",
"rev1": "",
"ver0": "6.7.80",
"ver1": ""
  },
  {
"_name": "vaa",
"rev0": "",
"rev1": "00852cb",
"ver0": "",
"ver1": "0.7"
]
  }

Another coworker replied with Scala equivalent. So I thought, why 
wouldn't I join the party and translate that to D :)


My best take so far is (with some D-intro comments 
https://run.dlang.io/is/GxsauU):


import std.stdio;
import std.algorithm;
import std.range;
import std.array;
import std.conv;
import std.json;

void main()
{
// not `immutable` to describe one less thing
const srv1 = [
"acs": ["ver": "1.2.3", "rev": "6f2260d"],
"cms": ["ver": "4.5", "rev": "b17a67e"],
"ots": ["ver": "6.7.80", "rev": "4f487d2"]];
const srv2 = [
"acs": ["ver": "1.2.3", "rev": "6f2260d"],
"cms": ["ver": "5.1", "rev": "2a56c53"],
"vaa": ["ver":"0.7", "rev": "00852cb"]];

string[string][] result;
chain(srv1.keys, srv2.keys)
.sort   
.uniq   
.each!( (uniqComp) {
auto verInfo = ["_name": uniqComp];
[srv1, srv2]
.enumerate
.each!( serv =>
["ver", "rev"].each!( prop =>
  verInfo[prop ~ 
serv.index.to!string]
  = serv.value.get(uniqComp, ["": 
""]).get(prop, ""))

);
/+ // The same as above and I like this better, 
actually

foreach(servIdx, serv; [srv1, srv2].enumerate){
foreach(prop; ["ver", "rev"])
verInfo[prop ~ servIdx.to!string]
= serv.get(uniqComp, ["": ""]).get(prop, 
"");

} +/

result ~= verInfo;
});
writeln("---");
writeln(JSONValue(result).toPrettyString());
writeln("---");
}

I think, most clear code would be with tripple `foreach`, so I'll 
go with that. But probably someone will come up with something 
better and range-ier.


Suggestion are welcome!

---
Alexander

[Issue 17462] Order of base interfaces affects compiler behavior

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17462

Rainer Schuetze  changed:

   What|Removed |Added

 CC||r.sagita...@gmx.de

--- Comment #3 from Rainer Schuetze  ---
I always considered it a great relief that you don't have to reimplement common
interfaces. Otherwise COM-programming would be much more verbose. What's the
reasoning to disallow it?

The old samples in dmd/samples also assume that IUnknown doesn't have to be
reimplemented.

--

Re: [theory] What is a type?

[Jonathan Marler via Digitalmars-d]

On Sunday, 10 October 2010 at 12:28:32 UTC, Justin Johansson 
wrote:

Specifically I have a problem in trying to implement
a functional language translator in D.  My target language
has a rather non-conventional type system, in which,
superficially at least, types can be described as being
Cartesian in nature. That is,
types in this system have two orthogonal dimensions:
(1) classical data-type (e.g. boolean, number, string,
object) and
(2) Kleene cardinality (occurrences) with respect to (1).

The axial origin of this Cartesian type-system correlates well
with the concept of the "top" type (AKA "Unit" in Scala)
and as the rather adhoc "void" type in many Algol-derived
languages such as C/C++/Java/D.

So along axis 1 we might broadly describe the classical
data types as item, boolean, number, string, object where
item is effectively either a superclass or variant of the
other mentioned types.

Along axis 2 we describe Kleene occurrences of 1 as may be
passed contractually to a receiving function.  These
occurrences may be enumerated six-fold as:
zeroOrMore
zeroOrOne
oneOrMore
exactlyZero
exactlyOne
none

Readers may see that, for example, zeroOrOne is a special
case (perhaps a subclass?) of zeroOrMore.  exactlyOne is
a special case of both zeroOrOne and oneOrMore (sounds like
multiple inheritance?).  OTOH, exactlyZero is a special
case of zeroOrOne, which, in turn, is a special case of
zeroOrmore.

none is a special case of all of the above and reflects
the cardinality facet of the return type of a function
that never returns (say as by throwing an exception).

To make this type system even more enigmatic lets add a
third dimension, taking the 2-D Cartesian type system
model to a 3-D Spatial model, by imagining a further
degree of freedom with respect to laziness of evaluation
(AKA closure of arguments).

Now having hopefully described that a type is something
that might well have multiple orthogonal aspects to its
identity, how would one go about implementing a dynamic
language with such a complex type system in D?

I realize that this is a complex topic and that it might
require better articulation than so far I have given.

Nevertheless, thanks for all replies,
Justin Johansson


I'm getting "nostalgia" from all the math terminology :)  Here 
are some of my thoughts:


You've taken one property, cardinality, and put that on one axis 
and then declared all other properties in your system should be 
orthogonal to cardinality.  But then you said that "string" was 
on the other axis, which itself is of type zeroOrMore(char), 
violating your own system.


You also need to take into account that cardinality is 
multi-dimensional. i.e. you could have zeroOrMore(char) or 
zeroOrMore(zeroOrMore(char)).


That being said, I don't think this model really get much closer 
to answering the original question, "what is a type?".


A while back I watched a cppcon talk from Dan Saks who defined 
what a data type was in C++:


https://www.youtube.com/watch?v=D7Sd8A6_fYU#t=58m59s

Note that the whole video also contains alot of good information. 
It explores the social aspects being a programmer and is 
definitely worth watching.


In his video he declares a data type as a "bundle of compile-time 
properties for an object", namely


1. size/alignment
2. set of values
3. set of permitted operations

This model is a very good breakdown of what a type is in C++.  
D's a bit more complex.  When you say "type" in D, there's alot 
more things you could be talking about so you either need to 
expand your definition of what a type is, or restrict the 
entities you consider to be types.  But these 3 properties are a 
good start :)


A bit off topic.  I find it frustrating that types always need to 
have these 3 properties.  Most of the time a programmer doesn't 
care about size/alignment, they just want the set of values and 
operations.  D can allow a programmer to do this using templates, 
but that "throws the baby out with the bath water".  You almost 
always require subset of properties.  Because template don't 
define any of the properties, you end up with cryptic template 
error messages.  D's tried to make the problem better by using 
conditional templates and C++ is trying to solve this with 
"Concepts". I've explored these ideas for a long time and am 
still currently developing my own methods for solving these 
problems. My latest idea is that you can create different "type 
interfaces".  At a minimum, I've defined a type to be a "pure 
function" that takes any value and maps it to a boolean 
indicating whether or not that value is a member of that type.  
That's the "minimum interface", but you could also have a type 
that declares other properties, such as, a set of "values", or 
size/alignment.  However, it's important to allow a developer to 
work with types that don't necessarily define all these 
properties for every time.  Anyway, I'm mostly just sharing some 
of my thoughts.  I have alot to say on this subject 

[Issue 17462] Order of base interfaces affects compiler behavior

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17462

Andrei Alexandrescu  changed:

   What|Removed |Added

 CC||and...@erdani.com

--- Comment #2 from Andrei Alexandrescu  ---
FWIW the Java code works without requiring the additional implementation:

interface Marker {}
interface Foo { void foo(); }

interface FooMarked extends Foo, Marker {}
interface MarkedFoo extends Marker, Foo  {}

class Base implements Foo { public void foo() {} }

class Derived1 extends Base implements FooMarked {} // Inherit Base.foo
class Derived2 extends Base implements MarkedFoo {} // Inherit Base.foo

--

Re: Proposed Phobos equivalent of wcswidth()

[Jonathan M Davis via Digitalmars-d]

On Monday, January 15, 2018 10:37:14 H. S. Teoh via Digitalmars-d wrote:
> On Mon, Jan 15, 2018 at 06:20:16PM +, Jack Stouffer via Digitalmars-d 
wrote:
> > On Monday, 15 January 2018 at 17:32:40 UTC, H. S. Teoh wrote:
> > > On Mon, Jan 15, 2018 at 02:14:56PM +, Simen Kjærås via
> > > Digitalmars-d
> > >
> > > wrote:
> > > > On Monday, 15 January 2018 at 13:34:09 UTC, Jack Stouffer wrote:
> > > > > std.utf.displayWidth
> > > >
> > > > +1
> > >
> > > [...]
> > >
> > > Why std.utf rather than std.uni, though?
> >
> > The way I understand it is that std.uni is (supposed to be) for
> > functions on individual unicode units (be they code units/points or
> > graphemes) and std.utf is for functions which handle operating on
> > unicode strings.
>
> Are you sure?  I thought std.utf was specifically dealing with UTF-*
> encodings, i.e., code units and conversions to/from code points, and
> std.uni was supposed to be for implementing Unicode algorithms and
> Unicode compliance in general, i.e., stuff that works at the code point
> level.

Your understanding of the division more or less matches mine, though I'm not
sure that the line is entirely clearcut. I would definitely think that
std.uni was the more appropriate place for such a function.

- Jonathan M Davis

[Issue 18240] New: core.stdc.wchar_ wmemset, etc. should be pure

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18240

  Issue ID: 18240
   Summary: core.stdc.wchar_ wmemset, etc. should be pure
   Product: D
   Version: D2
  Hardware: All
OS: All
Status: NEW
  Severity: minor
  Priority: P1
 Component: druntime
  Assignee: nob...@puremagic.com
  Reporter: n8sh.second...@hotmail.com

Functions in core.stdc.wchar_ should have the same purity as the corresponding
non-wide functions in core.stc.string.

--

Re: Proposed Phobos equivalent of wcswidth()

[H. S. Teoh via Digitalmars-d]

On Mon, Jan 15, 2018 at 06:20:16PM +, Jack Stouffer via Digitalmars-d wrote:
> On Monday, 15 January 2018 at 17:32:40 UTC, H. S. Teoh wrote:
> > On Mon, Jan 15, 2018 at 02:14:56PM +, Simen Kjærås via Digitalmars-d
> > wrote:
> > > On Monday, 15 January 2018 at 13:34:09 UTC, Jack Stouffer wrote:
> > > > std.utf.displayWidth
> > > 
> > > +1
> > [...]
> > 
> > Why std.utf rather than std.uni, though?
> 
> The way I understand it is that std.uni is (supposed to be) for
> functions on individual unicode units (be they code units/points or
> graphemes) and std.utf is for functions which handle operating on
> unicode strings.

Are you sure?  I thought std.utf was specifically dealing with UTF-*
encodings, i.e., code units and conversions to/from code points, and
std.uni was supposed to be for implementing Unicode algorithms and
Unicode compliance in general, i.e., stuff that works at the code point
level.


> Obviously there are exceptions. I think "they" put graphemeStride in
> std.uni because Grapheme was defined there and it seemed reasonable at
> the time.  But, generally I think utf stuff should go into std.utf.

But displayWidth isn't really directly related to UTF (i.e., the
encoding of Unicode code points).  It seems to me to be more to do with
processing Unicode in general, though, granted, the optimizations I
implemented are kinda in a grey zone between dealing with Unicode proper
(i.e., with code points) vs. working with code units.


T

-- 
Klein bottle for rent ... inquire within. -- Stephen Mulraney

[Issue 18239] std.experimental.allocator fillWithMemcpy could use memset when T.sizeof==1

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18239

--- Comment #2 from Nathan S.  ---
(In reply to Nathan S. from comment #1)
> Could also use wmemset when T.sizeof == wint_t.sizeof

Unfortunately core.stdc.wchar_.wmemset isn't marked as pure so this would cause
some tests to fail.

--

[Issue 18239] std.experimental.allocator fillWithMemcpy could use memset when T.sizeof==1

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18239

Nathan S.  changed:

   What|Removed |Added

Summary|std.experimental.allocator  |std.experimental.allocator
   |fillWithMemcpy could use|fillWithMemcpy could use
   |memset/wmemset for  |memset when T.sizeof==1
   |T.sizeof==1 or  |
   |wint_t.sizeof   |

--

[Issue 18239] std.experimental.allocator fillWithMemcpy could use memset/wmemset for T.sizeof==1 or wint_t.sizeof

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18239

--- Comment #1 from Nathan S.  ---
Could also use wmemset when T.sizeof == wint_t.sizeof

--

[Issue 18239] std.experimental.allocator fillWithMemcpy could use memset/wmemset for T.sizeof==1 or wint_t.sizeof

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18239

Nathan S.  changed:

   What|Removed |Added

Summary|std.experimental.allocator  |std.experimental.allocator
   |fillWithMemcpy could use|fillWithMemcpy could use
   |memset when T.sizeof==1 |memset/wmemset for
   ||T.sizeof==1 or
   ||wint_t.sizeof

--

mysql-native: Prepared statements: Direction and future

[Nick Sabalausky (Abscissa) via Digitalmars-d-announce]

I've posted (what basically amounts to an article) about my current 
thoughts on addressing Prepared's current downsides in the next release 
(v2.0.0), as well as a little bit of future direction of the lib.


Anyone interested in mysql-native's prepared statements (especially 
their interplay with connection pools) is encouraged to take a look and 
share any thoughts:


https://github.com/mysql-d/mysql-native/issues/95#issuecomment-357757013

Re: Proposed Phobos equivalent of wcswidth()

[Jack Stouffer via Digitalmars-d]

On Monday, 15 January 2018 at 17:32:40 UTC, H. S. Teoh wrote:
On Mon, Jan 15, 2018 at 02:14:56PM +, Simen Kjærås via 
Digitalmars-d wrote:
On Monday, 15 January 2018 at 13:34:09 UTC, Jack Stouffer 
wrote:

> std.utf.displayWidth

+1

[...]

Why std.utf rather than std.uni, though?


The way I understand it is that std.uni is (supposed to be) for 
functions on individual unicode units (be they code units/points 
or graphemes) and std.utf is for functions which handle operating 
on unicode strings. Obviously there are exceptions. I think 
"they" put graphemeStride in std.uni because Grapheme was defined 
there and it seemed reasonable at the time. But, generally I 
think utf stuff should go into std.utf.

[Issue 18239] New: std.experimental.allocator fillWithMemcpy could use memset when T.sizeof==1

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18239

  Issue ID: 18239
   Summary: std.experimental.allocator fillWithMemcpy could use
memset when T.sizeof==1
   Product: D
   Version: D2
  Hardware: All
OS: All
Status: NEW
  Severity: enhancement
  Priority: P1
 Component: phobos
  Assignee: nob...@puremagic.com
  Reporter: n8sh.second...@hotmail.com

Current function in std.experimental.allocator.package:
```
private void fillWithMemcpy(T)(void[] array, auto ref T filler) nothrow
{
import core.stdc.string : memcpy;
import std.algorithm.comparison : min;
if (!array.length) return;
memcpy(array.ptr, , T.sizeof);
// Fill the array from the initialized portion of itself exponentially.
for (size_t offset = T.sizeof; offset < array.length; )
{
size_t extent = min(offset, array.length - offset);
memcpy(array.ptr + offset, array.ptr, extent);
offset += extent;
}
}
```

When T.sizeof==1 we could use memset instead.

If this change is made it might be a good idea to change the name of the
function to avoid an implicit contract that it uses the memcpy function.

--

Does it have an http2 server/client lib like in golang?

[Cergoo via Digitalmars-d-learn]

subj

Re: How to run vibe.d web app in XAMPP server ?

[welkam via Digitalmars-d]

On Monday, 15 January 2018 at 06:22:13 UTC, Jayam wrote:

Is there any way how to deploy the vibe.d web app into XAMPP ?


No you cant deploy vibe.d web app into XAMPP. What you can do is 
to install vibe.d to the same server and tell apache to proxy all 
requests to vibe.d.


I dont know enough about servers to tell you exactly how to do it 
but it should be the same as setting up node.js.

https://stackoverflow.com/questions/9831594/apache-and-node-js-on-the-same-server

I hope this helps

Re: Proposed Phobos equivalent of wcswidth()

[H. S. Teoh via Digitalmars-d]

On Mon, Jan 15, 2018 at 02:14:56PM +, Simen Kjærås via Digitalmars-d wrote:
> On Monday, 15 January 2018 at 13:34:09 UTC, Jack Stouffer wrote:
> > std.utf.displayWidth
> 
> +1
[...]

Why std.utf rather than std.uni, though?


T

-- 
ASCII stupid question, getty stupid ANSI.

Re: Article: Fuzzing D code with LDC

[Johan Engelen via Digitalmars-d-announce]

On Monday, 15 January 2018 at 09:49:24 UTC, Temtaime wrote:


// `Throwable`s thrown are not bugs (in contrast to `Errors`).

They _can_ be bugs.
class Error : Throwable
class Exception : Throwable


Good catch ( ;-) ) thanks.

-Johan

Re: Cannot use local lambda as parameter to non-global template

[Nordlöw via Digitalmars-d-learn]

On Monday, 15 January 2018 at 15:27:23 UTC, Meta wrote:

void main()
{
auto arr = [1, 2, 3];
arr.remove!(_ => _ == 1);
writeln(arr);
}

Or was that code meant as an example?


The problem occurs when the templated function is a member of the 
struct `arr`. I've moved the algorithm into a free function here


https://github.com/nordlow/phobos-next/blob/master/src/hashmap_or_hashset.d#L1190

instead. I've changed the name to `removeAllMatching` for now.

Re: Cannot use local lambda as parameter to non-global template

[Ali Çehreli via Digitalmars-d-learn]

On 01/15/2018 07:27 AM, Meta wrote:

On Monday, 15 January 2018 at 13:55:57 UTC, Nordlöw wrote:



The function `remove` is a templated member of a struct instance `x`.


Can you give a bit more context? The following code does not cause a 
compile error:


import std.stdio;
import std.algorithm;

void main()
{
     auto arr = [1, 2, 3];
     arr.remove!(_ => _ == 1);
     writeln(arr);
}

Or was that code meant as an example?


import std.algorithm;

struct S {
int[] elements;

void remove(alias func)() {
// ...
}

void remove(string s)() {
foreach (a; elements) {
const cond = mixin(s);
if (cond) {
// do remove
}
}
}
}

void main()
{
auto s = S();
s.remove!"a == 11"();

// Fails compilation:
// s.remove!(_ => _ == 1);
}

Ali

Re: run.dlang.io can now display ASM + AST + IR

[Martin Tschierschke via Digitalmars-d-announce]

On Sunday, 14 January 2018 at 04:18:41 UTC, Seb wrote:
It was bad weather in Munich on Saturday, so run.dlang.io got a 
couple of new cool features:


1) Assembly output

...

2) AST of DMD frontend (after semantic analysis)

...

3) IR (LDC only)

...

4) Permanent flags
5) Stores the latest source file in the persistent localStorage 
of your browser

6) Small UI updates


Yes! Very cool!

Re: Proposed Phobos equivalent of wcswidth()

[Dominikus Dittes Scherkl via Digitalmars-d]

On Monday, 15 January 2018 at 15:08:24 UTC, Kagamin wrote:
columnWidth as it only makes sense for column-oriented text 
display.


I think displayWidth is better, because "width" is directly 
linked to hozizontal direction (else it would be called hight), 
and setting text in colums would still take additional steps to 
be set correct.
Also "display" indicates that it has nothing to do with the 
string length, which is good to avoid confusion.

Web Application Development

[Viewport Tech via Digitalmars-d]

We create web applications from the ground up, tailored to your 
specific needs and that of your business. Weather you need to 
digitise an existing paper-based form or you want to build a 
ground-breaking social network. We've got it covered. We use the 
latest languages, frameworks and development techniques available 
to ensure your application is future proofed with the most 
reliable and secure of technology.




https://viewport-tech.com/web-application-development

Re: String Type Usage. String vs DString vs WString

[SimonN via Digitalmars-d-learn]

On Monday, 15 January 2018 at 14:44:46 UTC, Adam D. Ruppe wrote:

On Monday, 15 January 2018 at 06:18:27 UTC, SimonN wrote:
D's foreach [...] will autodecode and silently iterate over 
dchar, not char, even when the input is string


That's not true. foreach will only decode on demand:
foreach(c; s) { /* c is a char here, it goes over bytes */ }


Thanks for the correction! Surprised I got foreach(c, s) wrong, 
its non-decoding iteration is even the prominent example in TDPL.


Even `each`, the template function that implements a foreach, 
still infers as char:


"aä".each!writeln; // prints a plus two broken characters

Only `map`



When I wrote "D's ranges", I meant Phobos's range-producing 
templates; a range itself is again encoding-agnostic.

Re: String Type Usage. String vs DString vs WString

[Jonathan M Davis via Digitalmars-d-learn]

On Monday, January 15, 2018 14:56:33 Kagamin via Digitalmars-d-learn wrote:
> On Monday, 15 January 2018 at 06:18:27 UTC, SimonN wrote:
> > D's foreach and D's ranges will autodecode and silently iterate
> > over dchar, not char
>
> foreach doesn't do it silently, decoding must be requested from
> it by explicitly specifying element type, it can also encode this
> way.

Yeah, one of the joys of that is that you have to be careful of using
foreach in range-based functions, because if you haven't specialized for
strings, and you use foreach without specifying the element type, then when
your function template is instantiated with a string, the foreach won't
match what front does.

I really don't have any complaints about how foreach does this aside from
the fact that it doesn't currently use the replacement character (so, it
will throw on invalid Unicode if it's told to decode), but the way that
interacts with Phobos is poor.

Ideally, we'd get rid of auto-decoding, and we'd get rid of the whole
exception on bad Unicode thing and just use the replacement character, but
since changing it would break a lot of code... :|

- Jonathan M Davis

Re: What's equivalent to C#'s select?

[Simen Kjærås via Digitalmars-d-learn]

On Monday, 15 January 2018 at 15:24:50 UTC, Marc wrote:
I just thought that filter() could be evaluated at compile time 
too, as others function that I've used so far. Sometimes I 
don't know if a native function can be evaluated at compile 
time until I do enum x = func();


Yeah, it takes some getting used to what happens when and how 
these interact. I can recommend H. S. Teoh's writeup: 
https://wiki.dlang.org/User:Quickfur/Compile-time_vs._compile-time


if I want to have minimum runtime code to filter out immutable 
strings, the first one is better right?


Indeed. It generates the equivalent code to just writing the 
writeln()s you want, with no run-time overhead.


--
  Simen

Re: I want to transmit the class name and the member name in the method

[Martin Nowak via Digitalmars-d-learn]

On Friday, 5 January 2018 at 07:40:14 UTC, Brian wrote:

auto db = new ORM;
auto users = 
db.select(User).where(email.like("*@hotmail.com")).limit(10);


Expression templates are a dead-end for any non-trivial queries.
You have to embrace SQL to properly use RDMS, at the cost of 
beginners having to learn it.
There is no free lunch and the inefficient queries ppl. are 
running with Rails examplify what happens, when you pretend it's 
possible to use technology without understanding it.


I'm actively working towards a design that allows full 
compile-time typing with plain SQL commands. This will still take 
a while, but I hope we can see an alpha in 2018H1.

http://dconf.org/2016/talks/nowak.html

alias schema = AliasSeq!(User, MailAddress, Book, Lending);
DB!schema db = DB!schema(SQLite("local.db")); // connecting 
checks for missing/additional migrations
db = DB!schema(MySQL("localhost", 3306)); // DB wrapper is driver 
agnostic

// Full ANSI SQL
// driver-specific functions when picking the driver at compile 
time

// You can always exec dynamic queries on the underlying driver

foreach (r; db.exec!(q"SQL
SELECT u.name, m.addr, CONCAT(b.title, ';') books
FROM users u
JOIN mail_addresses m ON m.user_id = u.id AND NOT 
u.can_overdraw
JOIN lendings l ON l.user_id = u.id AND DATEDIFF(NOW(), 
l.end_date) >= 7

JOIN books b ON b.lending_id = l.id
WHERE b.amount < 20
GROUP BY u.id
SQL
)
sendMail(r.name, r.addr, r.books.splitter(';'));

More concise stuff is possible with heavy compile-time trickery 
(https://dpaste.dzfl.pl/cd375ac594cf) without incurring dreaded 
1+N queries or even any unnecessary SELECT fields.


foreach (u; db.select!User.where!"NOT can_overdraw")
{
sendMail(u.name, u.mail.addr, u.lendings // no 1+N here
.where!"DATEDIFF(NOW(), end_date) >= 7 AND book.amount < 
20")

.map!(l => l.book.Reminder)); // client side range API
}

This has become even more of a challenge since we plan to make it 
a @safe @nogc poster child.


If anyone wants to help with this project please contact me.

At the moment reworked @safe @nogc database drivers would be most 
helpful.

I'll soon publish a small RC, Uniq, Weak library.
Unbuffered IO foundations are already here 
https://github.com/MartinNowak/io, but not yet practically 
proven, and still lacking vibe-core scheduler/eventcore 
integration.

Re: Cannot use local lambda as parameter to non-global template

[Meta via Digitalmars-d-learn]

On Monday, 15 January 2018 at 13:55:57 UTC, Nordlöw wrote:

Why do I get errors like

template instance remove!((_) => _ == 1) cannot use local 
'__lambda5' as parameter to non-global template remove()(in K 
key)


for

x.remove!(_ => _ == 1);

but not for

x.remove!"a == 11";

?

How are these two lambdas different?

The function `remove` is a templated member of a struct 
instance `x`.


Can you give a bit more context? The following code does not 
cause a compile error:


import std.stdio;
import std.algorithm;

void main()
{
auto arr = [1, 2, 3];
arr.remove!(_ => _ == 1);
writeln(arr);
}

Or was that code meant as an example?

Re: What's equivalent to C#'s select?

[Marc via Digitalmars-d-learn]

On Monday, 15 January 2018 at 07:37:42 UTC, Simen Kjærås wrote:

On Sunday, 14 January 2018 at 22:07:22 UTC, Marc wrote:

thanks, can i use it at compile time as well?

	enum isMutableString(string field) = 
is(typeof(__traits(getMember, >C, field)) == string);

static foreach(field; [FieldNameTuple!C].filter!(f =>

isMutableString!(f))) {

writeln(field);
}


You're mixing compile-time and run-time logic here in a way 
that D doesn't allow. In particular, isMutableString requires 
the passed string to be a compile-time constant, and filter 
works on run-time values.


I just thought that filter() could be evaluated at compile time 
too, as others function that I've used so far. Sometimes I don't 
know if a native function can be evaluated at compile time until 
I do enum x = func();


There are a few different ways to resolve this. First, std.meta 
has the Filter template, which behaves much in the same way as 
std.algorithm.filter, but with compile-time tuples:


static foreach (field; Filter!(isMutableString, 
FieldNameTuple!C)) {

writeln(field);
}

The other option is to rewrite isMutableString to work with 
run-time values:


bool isMutableString(string field) {
switch (field) {
foreach (cField; FieldNameTuple!C) {
case cField:
return is(typeof(__traits(getMember, C, 
cField)) == string);

}
default:
return false;
}
}
static foreach(field; [FieldNameTuple!C].filter!(f => 
isMutableString(f))) {

writeln(field);
}

Both of these give the same output, and should be what you want.

--
  Simen


That's exactly it! That Filter() from std.algorithm works like I 
wanted :) nice solution also with rewrite the function to work 
with run-time so that i can use with filter() but if I want to 
have minimum runtime code to filter out immutable strings, the 
first one is better right?

Re: Cannot use local lambda as parameter to non-global template

[Jacob Carlborg via Digitalmars-d-learn]

On 2018-01-15 14:55, Nordlöw wrote:

Why do I get errors like

template instance remove!((_) => _ == 1) cannot use local '__lambda5' as 
parameter to non-global template remove()(in K key)


for

     x.remove!(_ => _ == 1);

but not for

     x.remove!"a == 11";

?

How are these two lambdas different?

The function `remove` is a templated member of a struct instance `x`.


The difference is that the string version would not capture the 
surrounding context while the lambda version does. It's something 
related to that the lambda needs to capture both the this object, since 
"remove" is member of a struct, and capturing the local context of where 
"remove" is called. A lambda/delegate can only have one context pointer. 
There's an issue already reported for this.


--
/Jacob Carlborg

Re: Proposed Phobos equivalent of wcswidth()

[Kagamin via Digitalmars-d]

columnWidth as it only makes sense for column-oriented text 
display.

Re: Using Postgres connection functions

[Joe via Digitalmars-d-learn]

On Monday, 15 January 2018 at 02:28:29 UTC, Matthias Klumpp wrote:
In any case, please don't start another Postgres library and 
consider contributing to one of the existing ones, so that we 
maybe have one really awesome, 100% complete library at some 
point.


If, on the other hand, your goal is to learn about the 
low-level Postgres interface and not just to have a Postgres 
interface for an application you develop, by all means, play 
with it :-)


At this point, I am indeed learning about low-level Postgres 
interfaces (but not so low-level as the client-server protocol) 
as a way to understand the challenges of interfacing D to C.


However, as part of the Pyrseas open source project, which I 
maintain, I had started to create a Postgres interface in Python 
inspired by The Third Manifesto, as opposed to ORMs like 
SQLAlchemy (see 
https://pyrseas.wordpress.com/2013/03/07/a-pythonic-ttm-inspired-interface-to-postgresql-requirements/). I got criticized for "reinventing the wheel" but I believe TTM, if properly done, is quite different from an ORM.


I understand your concern about not starting another PG library. 
From the cursory investigation of the existing libraries, I think 
they span a spectrum, with ddb at one end (low-level protocol), 
then derelict-pq (low-level binding over libpq), ddbc at the 
opposite end (multi-DBMS support) and several others in between. 
So I  guess the real problem is with the proliferation in the 
latter group.

Re: Cannot use local lambda as parameter to non-global template

[Simen Kjærås via Digitalmars-d-learn]

On Monday, 15 January 2018 at 13:55:57 UTC, Nordlöw wrote:

Why do I get errors like

template instance remove!((_) => _ == 1) cannot use local 
'__lambda5' as parameter to non-global template remove()(in K 
key)


for

x.remove!(_ => _ == 1);

but not for

x.remove!"a == 11";

?

How are these two lambdas different?

The function `remove` is a templated member of a struct 
instance `x`.


It's a bit involved, but boils down to this: lambdas in D can 
only have one context pointer. A simple example:


class Foo {
int n = 2;
int run(alias fun)(int m) { return fun(n, m); }
}

unittest {
int a = 3;
int fn(int n, int m) { return a + n + m; }
assert((new Foo).run!fn(4) == 9);
}

fn obviously requires a pointer to the context in the unittest 
block, since it uses 'a' in that context. Somewhat less 
obviously, it also needs a pointer to the Foo instance in which 
it is run. Since 2 > 1, this fails. There's a bug reported for 
it: https://issues.dlang.org/show_bug.cgi?id=5710, and even a 
$200 bounty for fixing it: 
https://www.bountysource.com/issues/1375082


The bug report is almost seven years old, so it seems this is a 
hard bug to squash.


Luckily, there are some workarounds. One you've already found. 
Others include moving templates to scopes where less context is 
needed (e.g. moving a function template that is associated with a 
class, but doesn't need to be part of it, outside the class), and 
marking your lambdas 'static'. A static lambda does not have a 
context pointer to the scope in which it is declared, and so 
cannot use variables declared in it. For instance, fn above uses 
'a' in the same scope, and so cannot be marked static.


--
  Simen

Re: String Type Usage. String vs DString vs WString

[Kagamin via Digitalmars-d-learn]

On Monday, 15 January 2018 at 06:18:27 UTC, SimonN wrote:
D's foreach and D's ranges will autodecode and silently iterate 
over dchar, not char


foreach doesn't do it silently, decoding must be requested from 
it by explicitly specifying element type, it can also encode this 
way.

Re: String Type Usage. String vs DString vs WString

[Adam D. Ruppe via Digitalmars-d-learn]

On Monday, 15 January 2018 at 06:18:27 UTC, SimonN wrote:
D's foreach [...] will autodecode and silently iterate over 
dchar, not char, even when the input is string



That's not true. foreach will only decode on demand:

string s;

foreach(c; s) { /* c is a char here, it goes over bytes */ }
foreach(char c; s) { /* c is a char here, same as above */ }
foreach(dchar c; s) { /* c is a dchar - this decodes */ }



Autodecoding is a Phobos library artifact, NOT something in the D 
language itself.

Re: Proposed Phobos equivalent of wcswidth()

[Simen Kjærås via Digitalmars-d]

On Monday, 15 January 2018 at 13:34:09 UTC, Jack Stouffer wrote:

std.utf.displayWidth


+1

--
  Simen

[Issue 18230] multiwayUnion sets wrong pred lambdas

[d-bugmail--- via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=18230

RazvanN  changed:

   What|Removed |Added

 CC||razvan.nitu1...@gmail.com

--- Comment #1 from RazvanN  ---
PR : https://github.com/dlang/phobos/pull/6032

--

Cannot use local lambda as parameter to non-global template

[Nordlöw via Digitalmars-d-learn]

Why do I get errors like

template instance remove!((_) => _ == 1) cannot use local 
'__lambda5' as parameter to non-global template remove()(in K key)


for

x.remove!(_ => _ == 1);

but not for

x.remove!"a == 11";

?

How are these two lambdas different?

The function `remove` is a templated member of a struct instance 
`x`.

Re: Bump the minimal version required to compile DMD to 2.076.1

[Daniel Kozak via Digitalmars-d]

Btw, ther is a gdc which stil uses c++ version of dfrontend, so on DragonFlyBSD
you can build dmd using gdc.

On Mon, Jan 15, 2018 at 2:25 PM, Daniel Kozak  wrote:

> So why not to use cross compilation?
>
> On Mon, Jan 15, 2018 at 2:10 PM, Joakim via Digitalmars-d <
> digitalmars-d@puremagic.com> wrote:
>
>> On Monday, 15 January 2018 at 12:15:27 UTC, Temtaime wrote:
>>
>>> And what builds C++ compiler from source ? :)
>>>
>>
>> The system C/C++ compiler is already built and there, obviously.  Since
>> nobody ships a D compiler with their OS, I'm not sure how you think that's
>> relevant.
>>
>> On Monday, 15 January 2018 at 12:36:04 UTC, Daniel Kozak wrote:
>>
>>> Exactly, there is no reason to build 2.067, 2.076, and 2.078, just build
>>> the latest one with the previos one. It is common (in case you do not have
>>> dlang compiler in your distribution) to start with downloading existing
>>> binary and compile lastest version as a package, then you can use this
>>> package as a dependency for building new versions.
>>>
>>
>> There is no existing binary for an OS that doesn't have a port yet!
>>
>> Take the current DragonFlyBSD port that's being done: he had to port both
>> dmd 2.067, which is written in C++, and the latest dmd master to DragonFly,
>> in order to have source packages for their ports repository:
>>
>> https://github.com/dlang/dmd/pull/7463
>>
>> If you bump the D compiler required for latest master, he'll have to port
>> every bumped D compiler too, ie 2.067, 2.076, and 2.078, in order to have a
>> source package.  That's going to be a huge pain that will stop many from
>> doing the initial port.
>>
>
>

Re: String Type Usage. String vs DString vs WString

[Patrick Schluter via Digitalmars-d-learn]

On Monday, 15 January 2018 at 04:27:15 UTC, Jonathan M Davis 
wrote:
On Monday, January 15, 2018 03:14:02 Tony via 
Digitalmars-d-learn wrote:

On Monday, 15 January 2018 at 02:09:25 UTC, rikki cattermole

wrote:
> Unicode has three main variants, UTF-8, UTF-16 and UTF-32. 
> The size of a code point is 1, 2 or 4 bytes.


I think to be technically correct, 1 (UTF-8), 2 (UTF-16) or 4
(UTF-32) bytes are referred to as "code units" and the size of 
a

code point varies in UTF-8 and UTF-16.


Yes, for UTF-8, a code unit is 8 bits, and there can be up to 6 
of them (IIRC) in a code point.


Nooo!!! Only 4 maximum for Unicode. Beyond that it's 
obsolete crap that is not Unicode since version 2 of Unicode.

Re: Proposed Phobos equivalent of wcswidth()

[Jack Stouffer via Digitalmars-d]

On Saturday, 13 January 2018 at 17:26:52 UTC, H. S. Teoh wrote:

...


Thanks for taking the time to do this.

And now the obligatory bikeshed: what should the Phobos 
equivalent of wcswidth be called?


std.utf.displayWidth

Re: Bump the minimal version required to compile DMD to 2.076.1

[Daniel Kozak via Digitalmars-d]

So why not to use cross compilation?

On Mon, Jan 15, 2018 at 2:10 PM, Joakim via Digitalmars-d <
digitalmars-d@puremagic.com> wrote:

> On Monday, 15 January 2018 at 12:15:27 UTC, Temtaime wrote:
>
>> And what builds C++ compiler from source ? :)
>>
>
> The system C/C++ compiler is already built and there, obviously.  Since
> nobody ships a D compiler with their OS, I'm not sure how you think that's
> relevant.
>
> On Monday, 15 January 2018 at 12:36:04 UTC, Daniel Kozak wrote:
>
>> Exactly, there is no reason to build 2.067, 2.076, and 2.078, just build
>> the latest one with the previos one. It is common (in case you do not have
>> dlang compiler in your distribution) to start with downloading existing
>> binary and compile lastest version as a package, then you can use this
>> package as a dependency for building new versions.
>>
>
> There is no existing binary for an OS that doesn't have a port yet!
>
> Take the current DragonFlyBSD port that's being done: he had to port both
> dmd 2.067, which is written in C++, and the latest dmd master to DragonFly,
> in order to have source packages for their ports repository:
>
> https://github.com/dlang/dmd/pull/7463
>
> If you bump the D compiler required for latest master, he'll have to port
> every bumped D compiler too, ie 2.067, 2.076, and 2.078, in order to have a
> source package.  That's going to be a huge pain that will stop many from
> doing the initial port.
>

Re: Bump the minimal version required to compile DMD to 2.076.1

[Joakim via Digitalmars-d]

On Monday, 15 January 2018 at 12:15:27 UTC, Temtaime wrote:

And what builds C++ compiler from source ? :)


The system C/C++ compiler is already built and there, obviously.  
Since nobody ships a D compiler with their OS, I'm not sure how 
you think that's relevant.


On Monday, 15 January 2018 at 12:36:04 UTC, Daniel Kozak wrote:
Exactly, there is no reason to build 2.067, 2.076, and 2.078, 
just build the latest one with the previos one. It is common 
(in case you do not have dlang compiler in your distribution) 
to start with downloading existing binary and compile lastest 
version as a package, then you can use this package as a 
dependency for building new versions.


There is no existing binary for an OS that doesn't have a port 
yet!


Take the current DragonFlyBSD port that's being done: he had to 
port both dmd 2.067, which is written in C++, and the latest dmd 
master to DragonFly, in order to have source packages for their 
ports repository:


https://github.com/dlang/dmd/pull/7463

If you bump the D compiler required for latest master, he'll have 
to port every bumped D compiler too, ie 2.067, 2.076, and 2.078, 
in order to have a source package.  That's going to be a huge 
pain that will stop many from doing the initial port.

Re: Bump the minimal version required to compile DMD to 2.076.1

[Daniel Kozak via Digitalmars-d]

Exactly, there is no reason to build 2.067, 2.076, and 2.078, just build
the latest one with the previos one. It is common (in case you do not have
dlang compiler in your distribution) to start with downloading existing
binary and compile lastest version as a package, then you can use this
package as a dependency for building new versions.

On Mon, Jan 15, 2018 at 1:15 PM, Temtaime via Digitalmars-d <
digitalmars-d@puremagic.com> wrote:

> And what builds C++ compiler from source ? :)
>

Re: Bump the minimal version required to compile DMD to 2.076.1

[Temtaime via Digitalmars-d]

And what builds C++ compiler from source ? :)

I didn't succeed in creating an empty project for a long time

[Brian via Digitalmars-d]

zoujiaqing@Brian-XPS MINGW64 /d/Projects
$ dub init serializable -v
Using dub registry url 'https://code.dlang.org/'
Refreshing local packages (refresh existing: true)...
Looking for local package map at 
C:\ProgramData\dub\packages\local-packages.json
Looking for local package map at 
C:\Users\Brian\AppData\Roaming\dub\packages\local-packages.json

No package found in current working directory.