How to walk over two arrays by ref in beautyfull way?
How to?
I plan scan First array with checkers:
[checker, checker, checker]
...and store result to Second array:
[0, 0, 1]
In next code 'r' not reference. But expected ref.
import std.range : zip;
foreach(checker, ref r; zip(checkers, result.set)) {
r = checker();
}
What is the best way for speed and beautyfull D code?
Re: How to walk over two arrays by ref in beautyfull way?
On Monday, 10 June 2019 at 07:41:40 UTC, vitalfadeev wrote:
How to?
I plan scan First array with checkers:
[checker, checker, checker]
...and store result to Second array:
[0, 0, 1]
In next code 'r' not reference. But expected ref.
import std.range : zip;
foreach(checker, ref r; zip(checkers, result.set)) {
r = checker();
}
What is the best way for speed and beautyfull D code?
Detailed:
import std.range : zip;
struct Result {
byte[] set;
}
Result result;
alias Callback = bool delegate();
Callback[] checkers;
foreach(checker, ref r; zip(checkers, result.set)) {
r = checker();
}
Re: How to walk over two arrays by ref in beautyfull way?
On Monday, 10 June 2019 at 07:45:42 UTC, vitalfadeev wrote:
On Monday, 10 June 2019 at 07:41:40 UTC, vitalfadeev wrote:
How to?
I plan scan First array with checkers:
[checker, checker, checker]
...and store result to Second array:
[0, 0, 1]
In next code 'r' not reference. But expected ref.
import std.range : zip;
foreach(checker, ref r; zip(checkers, result.set)) {
r = checker();
}
What is the best way for speed and beautyfull D code?
Detailed:
import std.range : zip;
import std.stdio : writeln, write;
struct Result {
byte[] set;
}
alias Callback = bool function();
Callback[] checkers;
Result result;
bool false_cb() { return 0; }
bool true_cb() { return 1; }
void init() {
checkers ~= &false_cb;
checkers ~= &false_cb;
checkers ~= &true_cb;
result.set.length = checkers.length;
}
void check() {
foreach(checker, ref r; zip(checkers, result.set)) {
r = checker();
}
}
void print() {
foreach(r; result.set) {
write(r, " ");
}
writeln();
}
void main() {
init();
check();
print();
}
https://run.dlang.io/is/Plqcq5
Re: How to walk over two arrays by ref in beautyfull way?
On Monday, 10 June 2019 at 08:02:18 UTC, vitalfadeev wrote:
On Monday, 10 June 2019 at 07:45:42 UTC, vitalfadeev wrote:
On Monday, 10 June 2019 at 07:41:40 UTC, vitalfadeev wrote:
How to?
I plan scan First array with checkers:
[checker, checker, checker]
...and store result to Second array:
[0, 0, 1]
In next code 'r' not reference. But expected ref.
import std.range : zip;
foreach(checker, ref r; zip(checkers, result.set)) {
r = checker();
}
Replace zip with lockstep and your example works.
"zip is similar to lockstep, but lockstep doesn't bundle its
elements and uses the opApply protocol. lockstep allows reference
access to the elements in foreach iterations."
https://dlang.org/library/std/range/zip.html
"Function lockstep
Iterate multiple ranges in lockstep using a foreach loop. In
contrast to zip it allows reference access to its elements."
https://dlang.org/library/std/range/lockstep.html
Re: How to walk over two arrays by ref in beautyfull way?
On Mon, 2019-06-10 at 08:02 +, vitalfadeev via Digitalmars-d-learn
wrote:
[…]
Perhaps I am missing something that is critical to the example, but I
rewrote the code as:
import std.algorithm: map;
import std.stdio: writeln;
bool false_cb() { return false; }
bool true_cb() { return true; }
void main() {
auto checkers = [&false_cb, &false_cb, &true_cb];
auto result = map!(a => a())(checkers);
writeln(result);
}
This avoids the assumption that 0 is false and 1 is true. Also it makes
use of D map which seems to me what is happening at the core of the
code – using foreach and zip or lockstep just seems to be implementing
map. But as I say, I may be missing something.
--
Russel.
===
Dr Russel Winder t: +44 20 7585 2200
41 Buckmaster Roadm: +44 7770 465 077
London SW11 1EN, UK w: www.russel.org.uk
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Description: This is a digitally signed message part
Re: How to walk over two arrays by ref in beautyfull way?
Thanks! I happy! You are really powerfull!
Re: meson and d
On Sunday, 9 June 2019 at 13:13:28 UTC, dkd wrote: hi, i need some meson configuration that works with dmd and ldc my setting don't work. because meson complains it cannot find the d compiler. d compiler can be invoked on command line. i use : set dmd_path="path/to/d/base" set PATH=%dmd_path%\bin;%PATH%; mingw can be detected by setting GCC_HOME i use win7 and x86 meson 0.50.1 Are you using Windows? Meson's D support has never been tested there. In theory though you can point it at any D compiler by setting the "DC" environment variable.
curl: can't send email?
What wrong?
```
import std.net.curl;
void main() {
auto smtp = SMTP("smtps://smtp.gmail.com:465");
smtp.setAuthentication("qwe...@gmail.com", "password");
smtp.mailTo = ["std.net.curl.CurlException@std/net/curl.d(4364): Failed sending
data to the peer on handle 55FACCB58AC0
??:? pure @safe void
std.exception.bailOut!(std.net.curl.CurlException).bailOut(immutable(char)[], ulong, scope const(char)[]) [0x55facbd8db5e]
??:? pure @safe bool
std.exception.enforce!(std.net.curl.CurlException).enforce!(bool).enforce(bool, lazy const(char)[], immutable(char)[], ulong) [0x55facbd8dad1]
??:? void std.net.curl.Curl._check(int) [0x55facbd7209b]
??:? int
std.net.curl.Curl.perform(std.typecons.Flag!("throwOnError").Flag) [0x55facbd724c7]
??:? int
std.net.curl.SMTP.perform(std.typecons.Flag!("throwOnError").Flag) [0x55facbd71a80]
??:? _Dmain [0x55facbd69b6b]
Re: meson and d
hi, In theory though you can point it at any D compiler by setting the "DC" environment variable. i found at early morning, that by setting variable at system level(through my computer->environment setting) meson can detect d. it is the old usual way of setting variable that i almost forgot. i'll try the DC variable thanks. # i use mason because i am stuck with dub, i got lost in documentation. # reggae that i build from source, it works but at the end it throws exception.
Re: meson and d
On Monday, 10 June 2019 at 16:51:15 UTC, dkd wrote: hi, In theory though you can point it at any D compiler by setting the "DC" environment variable. i found at early morning, that by setting variable at system level(through my computer->environment setting) meson can detect d. it is the old usual way of setting variable that i almost forgot. i'll try the DC variable thanks. # i use mason because i am stuck with dub, i got lost in documentation. # reggae that i build from source, it works but at the end it throws exception. Where are you stuck within dub documentation? What do you want to achieve? Kind regards Andre
Re: curl: can't send email?
On Monday, 10 June 2019 at 16:10:07 UTC, Andrew wrote: What wrong? ``` import std.net.curl; [...] Curl smtp is a low level api. You need to know SMTP RFC. Please have a look here, this is a high level API on top of curl smtp: https://github.com/adamdruppe/arsd/blob/master/email.d Kind regards Andre
Re: if (X !is null && X.Y !is null) access crash
On 6/9/19 1:25 AM, Amex wrote: On Saturday, 8 June 2019 at 20:44:13 UTC, Steven Schveighoffer wrote: Try GC.addRef on the X reference, and see if it helps. This is during shutdown so I imagine simply turning off the GC should work fine? That way it prevents all cases rather than having to add a bunch of specific cases each time they crop up. I'm not sure if you can shut off the final collection. All you can do is disable collections during allocations. -Steve
Re: if (X !is null && X.Y !is null) access crash
On Monday, 10 June 2019 at 19:48:18 UTC, Steven Schveighoffer wrote: On 6/9/19 1:25 AM, Amex wrote: On Saturday, 8 June 2019 at 20:44:13 UTC, Steven Schveighoffer wrote: Try GC.addRef on the X reference, and see if it helps. This is during shutdown so I imagine simply turning off the GC should work fine? That way it prevents all cases rather than having to add a bunch of specific cases each time they crop up. I'm not sure if you can shut off the final collection. All you can do is disable collections during allocations. -Steve So far it seems to be working. It may prevent a collection at the right time that causes the problem... it all may be coincidence.
Re: Function parameters UDAs
On Wednesday, 14 November 2018 at 18:05:55 UTC, Adam D. Ruppe
wrote:
On Wednesday, 14 November 2018 at 16:28:19 UTC, Radu wrote:
Looks like that there is no easy way to extract a function
parameters UDA list.
Indeed, the only way I can find is kinda crazy:
---
void foo(int f, @("test") string s) {}
void main() {
static if(is(typeof(foo) Params == __parameters))
pragma(msg, __traits(getAttributes,
Params[1..2])); // get the second param
}
---
So, the process is:
1) alias the params with the static if + is() statement (this
is what std.traits.Parameters does internally)
2) slice the params! using params[0] will not work, but
params[0 .. 1] will.
3) get the attributes using the language function
Has anybody come up with a better solution yet? And why does
__traits(getAttributes, Parameters!foo[0]) not work in the first
place?
I am asking because I ran into a problem which does not seem
solvable to me using the above workaround:
I would like to iterate over all parameters of a function using
static foreach and then process each parameter's UDAs. But by
using static foreach on the parameter tuple, slicing it is not
possible anymore, so the suggested workaround does not work in
this case :(
The error does not appear if all parameters of the function are
symbols (e.g. structs), but it still does not work as expected
because the UDAs simply get dropped when iterating over the
parameter tuple. Here is an example:
import std;
struct Test
{}
void foo(@(1) Test x)
{
}
void main()
{
alias Params = Parameters!foo;
pragma(msg, Params);
static foreach(P; Params)
{
pragma(msg, P);
static foreach(uda; __traits(getAttributes, P))
{
pragma(msg, uda);
}
}
}
This prints
(@(1) Test)
Test
but I would expect it to print something like
(@(1) Test)
@(1) Test
@(1)
Re: Function parameters UDAs
On 11.06.19 01:12, Johannes Loher wrote:
I would like to iterate over all parameters of a function using static
foreach and then process each parameter's UDAs. But by using static
foreach on the parameter tuple, slicing it is not possible anymore, so
the suggested workaround does not work in this case :(
The workaround is to work with 1-length slices of your parameter
sequence instead of elements. You can still do that. You just can't
`foreach` over the parameters directly. Instead, iterate with an index
and use it to get slices:
-
import std;
struct Test
{}
void foo(@(1) Test x, @(2) @(3) float y)
{
}
void main()
{
alias Params = Parameters!foo;
pragma(msg, Params);
static foreach(i; 0 .. Params.length)
{{
alias P = Params[i .. i + 1];
pragma(msg, P);
static foreach(uda; __traits(getAttributes, P))
{
pragma(msg, uda);
}
}}
}
Prints:
(@(1) Test, @(tuple(2), tuple(3)) float)
(@(1) Test)
1
(@(tuple(2), tuple(3)) float)
2
3
Re: Function parameters UDAs
On Wednesday, 14 November 2018 at 16:28:19 UTC, Radu wrote:
Looks like that there is no easy way to extract a function
parameters UDA list.
The following:
```
import std.traits;
struct s { string foo; }
void foo(@s("aaa") int a, bool x);
void main()
{
alias P = Parameters!foo;
enum udas = __traits(getAttributes, P);
pragma(msg, udas);
}
```
will print `tuple(s("aaa"))`
but if you change `foo` to `void foo(int a, @s("aaa") bool x);`
you get `Error: first argument is not a symbol`
Is this a current limitation or I'm using the wrong approach?
I also, quite disappointed how UDAs doesn't work with enums. I
end up using struct + enum to simulate that, sometimes it's quite
a work.
Re: Function parameters UDAs
On Tuesday, 11 June 2019 at 02:04:13 UTC, Machine Code wrote:
I also, quite disappointed how UDAs doesn't work with enums. I
end up using struct + enum to simulate that, sometimes it's
quite a work.
They do now...
struct foo {}
enum Foo {
@foo a
}
void main() {
foreach(item; __traits(allMembers, Foo))
pragma(msg, __traits(getAttributes,
__traits(getMember, Foo,
item)));
}
Re: curl: can't send email?
On Monday, 10 June 2019 at 16:10:07 UTC, Andrew wrote: smtp.mailTo = [" There's a missing > in that string. idk if that is making a difference though, the error messages in this are awful.
Re: Function parameters UDAs
On Tuesday, 11 June 2019 at 02:24:49 UTC, Adam D. Ruppe wrote:
On Tuesday, 11 June 2019 at 02:04:13 UTC, Machine Code wrote:
I also, quite disappointed how UDAs doesn't work with enums. I
end up using struct + enum to simulate that, sometimes it's
quite a work.
They do now...
struct foo {}
enum Foo {
@foo a
}
void main() {
foreach(item; __traits(allMembers, Foo))
pragma(msg, __traits(getAttributes,
__traits(getMember, Foo,
item)));
}
Awesome! It came out and I didn't notice.
I want an exception message but my threaded callback just dies or crashes
Hi, when you use core.windows and LoadLibrary to load a DLL, and
that DLL will create a new thread and inside that it will call
back into your D app, is there something to special to be aware
of?
I've done it like with the CreateWindow and WndProc, but this
time I'm loading a compiled portaudio DLL and I give it a call
back. And I try to catch errors, but no matter what D Exception
(I tried out of range and null dereferencing) that thread seems
to either die silently (no hints in my console) or somehow fail
to make portaudio go on calling (I don't think so).
I just wanted to ask if you know any pitfall with this... I'll go
on using windbg and looking at things. I guess I should post a
complete project, but I have to clean it up, and you maybe don't
want to execute that portaudio32bit.dll from some unknown github
account.
The function for Portaudio looks like that:
extern(C) nothrow int patestCallback(
const void* inputBuffer,
void* outputBuffer,
uint framesPerBuffer,
const PaStreamCallbackTimeInfo* timeInfo,
PaStreamCallbackFlags statusFlags,
void* userData)
{
auto data = cast(paTestData*)userData;
auto out_ = cast(float*)outputBuffer;
auto ce = collectException(
data.callback(
data.frames_per_buffer,
&data.left_buf[0],
&data.right_buf[0]));
if(ce !is null)
{
assumeWontThrow(writeln(ce.toString));
TerminateProcess(GetCurrentProcess(), 0);
} else
{
assumeWontThrow(writeln("ce is null"));
}
for(uint i = 0; i < framesPerBuffer; ++i)
{
*out_++ = data.left_buf[i];
*out_++ = data.right_buf[i];
}
return PaStreamCallbackResult.paContinue;
}
...
...
I give it to Portaudio like that
{ auto err = Pa_OpenStream(
&stream,
null,
&outputParameters,
frames_per_second,
frames_per_buffer,
paClipOff,
&patestCallback,
&data);
Re: I want an exception message but my threaded callback just dies or crashes
I have cleaned it up, kind of. Just in case you want to compile it. The Zip contains some DLL from https://github.com/spatialaudio/portaudio-binaries where you can find the original if you want. https://gofile.io/?c=NpUxrJ I'm in general thinking of buying a Mac. I know it has not much to do with this, but debugging Swift code in Xcode must be so "gorgeous" as they say.
