Cmake dependency scanning
Do we have any D dependency scanning available for D in Cmake, just like the built in C/C++ dependency scanner which is handy, or do you have to use the option to compile everything into one module (--deps=full)? I have some problems when there is a mix of inlining and calling the separately compiled version from the same module, obviously.
Re: Timeout around function call
On Wednesday, 23 September 2020 at 20:58:00 UTC, Imperatorn wrote: On Wednesday, 23 September 2020 at 20:54:51 UTC, Imperatorn wrote: On Wednesday, 23 September 2020 at 20:44:51 UTC, Ali Çehreli wrote: On 9/23/20 1:19 PM, Imperatorn wrote: > [...] send a > [...] with timeout. [...] Sorry, I can't see the problem. Could you be more specific about what you want to achieve? Oops, I meant to reply to drathier I need to: - call a side-effect-free fn with a huge argument that I don't want to copy; this argument is then returned mostly unmodified wrapped in a new value - stop executing it if it runs for more than x seconds - get the return value from it if it finishes within x seconds (99.9% of time time) - let the main thread know what happened - the main thread should block until the fn call returns - the fn call should for sure stop executing before the main thread carries on - the size and complexity of the fn makes it pretty much impossible to add timeout checks everywhere to make it exit nicely; I need to kill it to be sure I didn't miss a case
Re: I need "windowsx.d" Someone can send It to me?
On Friday, 25 September 2020 at 15:03:56 UTC, Marcone wrote: I need windowsx.d but for I don't know the reason is not in dmd. Someone that have it can send to me? I don't know convert windowsx.h to windowsx.d I converting it using VisualD: https://pastebin.com/jzwKRnKZ Try it, maybe it works
Re: Safe to remove AA elements while iterating over it via .byKeyValue?
On Sunday, 27 September 2020 at 14:23:11 UTC, H. S. Teoh wrote: No. Modifying a container while iterating over it is, in general, a bad idea (unless the container is designed to be used that way, but even then, such removal is generally restricted), because it often leads to highly counterintuitive results. In the case of AA's, removing an element may lead to a rehashing, which reorders elements, and your iteration may miss some elements or repeat some elements or terminate prematurely. Even without a rehashing, you may encounter inconsistent behaviours, like some elements going "missing". I believe it's high time we start thinking about detecting these violations at compile-time. I recall it's in the spec somewhere so we should start a deprecation process at least for AAs.
assert format of a string before a mixin
I have a "variation" of "unaryFun" that I name "unaryProp" that,
basically, doesn't require to specify "a." at the beginning of
the expression.
template unaryProp(alias propName)
{
static assert(is(typeof(propName) : string), "Sorry, propName
must be an string");
auto unaryProp(ElementType)(auto ref ElementType a)
{
return mixin("a." ~ propName);
}
}
assert( "hello".unaryProp!"length" == 5 );
Problem is I need to check that "propName" is a valid property
name at compile time
i.e. checking this Regex expression
`^[a-zA-Z_]*[a-zA-Z0-9_]*[a-zA-Z][a-zA-Z0-9_]*$`
Is there any way to check a regular expression at compile time?
Re: A scheduled control signal with fibers?
On Sunday, 27 September 2020 at 16:39:45 UTC, Ali Çehreli wrote: On 9/27/20 6:33 AM, Ferhat Kurtulmuş wrote: > [...] Kurtulmuş wrote: >> [...] wrote: > [...] processing > [...] How many flame threads do you need? I thought one image processor and one flame thrower, no? Even if you have a dozen of each, main can start only the image processing threads and then each image processor can start its own flame thrower. Then, each pair will have an owner and a worker. [...] Thank you Ali (Bey). I will take those into account when finalizing my code. Your comments helped a lot!
Re: conflicting alias in package module
On 9/27/20 1:17 AM, 60rntogo wrote: On Sunday, 27 September 2020 at 03:33:20 UTC, Mike Parker wrote: package.d is for your external interface. Fair enough, thanks. This isn't an issue with package, it's an issue with a circular dependency. You are importing yourself and trying alias something to itself before that is defined, which has a conflict. -Steve
How to hide a function return type in order to wrap several functions into an associated array?
This is rather a generic implementation question not necessarily
related to D but I'd like to get some opinions.
I have a collection of functions that all have the same input, a
string. The output however is different and depending on what the
function does it can be ulong, double or bool. The problem is
that for each line of text I'd like to apply all these functions,
collect the results and write them into some file. For example,
auto numberOfPunctChars(string text)
{
const ulong cnt = text.filter!(c => c.isPunctuation).count;
return Feature!ulong("numberOfPunctChars", cnt);
}
auto ratioOfDigitsToChars(string text)
{
const double digits = numberOfDigitChars(text).val.to!double;
const double alphas = numberOfAlphaChars(text).val.to!double;
const double ratio = digits / (alphas > 0 ? alphas : digits);
return Feature!double("ratioOfDigitsToChars", ratio);
}
auto hasUnbalancedParens(string text)
{
const bool isBalanced = balancedParens(text, '(', ')') &&
balancedParens(text, '[', ']');
return Feature!bool("hasUnbalancedParens", !isBalanced);
}
As you can see, I created a templated Feature struct. This does
not help much because I also want to create an associative array
of ["functionName": ]. How can I define such
an array when "Feature!T function(string)[string] allFuns"
requires defining T beforehand and using auto is not possible?
I was thinking of having a Feature struct with 3 fiels of ulong,
double and bool members but then each Feature init would look
ugly imho "Feature("name", null, 1.5, null)". There should be a
another way.
Re: AA with class keys compared with identity instead of opEquals
On Sunday, 27 September 2020 at 18:39:10 UTC, Per Nordlöw wrote: How do I defined an AA with class as key where keys are compared using `is` instead of `opEquals`? Do I have to store the key as a `void*`? I got a good answer at https://dlang.slack.com/archives/C1ZDHBB2S/p1601234030016700
Re: AA with class keys compared with identity instead of opEquals
On Sunday, 27 September 2020 at 19:37:10 UTC, Per Nordlöw wrote: On Sunday, 27 September 2020 at 18:39:10 UTC, Per Nordlöw wrote: How do I defined an AA with class as key where keys are compared using `is` instead of `opEquals`? Do I have to store the key as a `void*`? I got a good answer at https://dlang.slack.com/archives/C1ZDHBB2S/p1601234030016700 Sorry I did not understand what you meant. It would be better if you share the answer here. I found this also https://dlang.org/library/std/traits/key_type.html, but I dont know if it is related.
Re: conflicting alias in package module
On 9/26/20 9:45 AM, Steven Schveighoffer wrote: On 9/26/20 3:33 AM, 60rntogo wrote: and this is an error: "struct pack.foo.Foo at source/pack/foo.d(3,1) conflicts with alias pack.bar.Foo at source/pack/bar.d(3,8)". I seems like the import in package.d sees Foo both in pack.foo and pack.bar, but I don't understand why this happens since the import in bar.d is private, isn't it? A selective import is equivalent to aliasing (to the public) the symbol as if it were defined in that scope. Just in case someone comes along and reads this, I was wrong about this. It's not a public import. -Steve
Re: How to hide a function return type in order to wrap several functions into an associated array?
On 9/27/20 11:54 AM, tastyminerals wrote:
> I have a collection of functions that all have the same input, a string.
> The output however is different and depending on what the function does
> it can be ulong, double or bool.
The following approach overcomes the different return type issue by
creating delegates that take string and return string:
auto numberOfPunctChars(string text) {
return 42;
}
auto ratioOfDigitsToChars(string text) {
return 1.5;
}
auto hasUnbalancedParens(string text) {
return true;
}
struct FeatureSet {
alias TakesString = string delegate(string);
TakesString[] features;
void register(Func)(Func func) {
// Here, we convert from a function returning any type
// to a delegate returning string:
features ~= (string s) {
import std.conv : text;
return func(s).text;
};
}
// Here, we apply all feature delegates and put the outputs
// into the provided output range.
void apply(O)(ref O outputRange, string s) {
import std.format : formattedWrite;
import std.algorithm : map;
outputRange.formattedWrite!"%-(%s\n%|%)"(features.map!(f => f(s)));
}
}
void main() {
auto featureSet = FeatureSet();
featureSet.register();
featureSet.register();
featureSet.register();
// lockingTextWriter() just makes an output range from
// an output stream.
import std.stdio;
auto output = stdout.lockingTextWriter;
featureSet.apply(output, "hello world");
// As another example, you can use an Appender as well:
import std.array : Appender;
auto app = Appender!(char[])();
featureSet.apply(app, "goodbye moon");
writefln!"Appender's content:\n%s"(app.data);
}
Ali
Re: assert format of a string before a mixin
On Sunday, 27 September 2020 at 21:38:43 UTC, ddcovery wrote: i.e. checking this Regex expression `^[a-zA-Z_]*[a-zA-Z0-9_]*[a-zA-Z][a-zA-Z0-9_]*$` Is there any way to check a regular expression at compile time? Not really and I'd actually suggest not trying because even if it did work, it'd probably be very slow. But that regex there is pretty easy to translate to a little hand-written loop function that would do the job runtime, ctfe both and do it quickly.
Re: assert format of a string before a mixin
On Sunday, 27 September 2020 at 21:41:25 UTC, Adam D. Ruppe wrote: On Sunday, 27 September 2020 at 21:38:43 UTC, ddcovery wrote: i.e. checking this Regex expression `^[a-zA-Z_]*[a-zA-Z0-9_]*[a-zA-Z][a-zA-Z0-9_]*$` Is there any way to check a regular expression at compile time? Not really and I'd actually suggest not trying because even if it did work, it'd probably be very slow. But that regex there is pretty easy to translate to a little hand-written loop function that would do the job runtime, ctfe both and do it quickly. Thanks Adam.
AA with class keys compared with identity instead of opEquals
How do I defined an AA with class as key where keys are compared using `is` instead of `opEquals`? Do I have to store the key as a `void*`?
Re: AA with class keys compared with identity instead of opEquals
On Sunday, 27 September 2020 at 18:39:10 UTC, Per Nordlöw wrote: How do I defined an AA with class as key where keys are compared using `is` instead of `opEquals`? Do I have to store the key as a `void*`? By looking at object.d and aaA.d of druntime, I d say you don't need to use void*. Object class has required infrastructure ready for using classes aa keys (have not tried though). Object class has both toHash and opEquals already implemented.
Re: AA with class keys compared with identity instead of opEquals
On Sunday, 27 September 2020 at 18:56:15 UTC, Ferhat Kurtulmuş wrote: By looking at object.d and aaA.d of druntime, I d say you don't need to use void*. Object class has required infrastructure ready for using classes aa keys (have not tried though). Object class has both toHash and opEquals already implemented. That's gonna be much slower. And I need key's to be checked for equivalence ,not equality.
Re: How to hide a function return type in order to wrap several functions into an associated array?
On Sunday, 27 September 2020 at 18:54:11 UTC, tastyminerals wrote:
This is rather a generic implementation question not
necessarily related to D but I'd like to get some opinions.
I have a collection of functions that all have the same input,
a string. The output however is different and depending on what
the function does it can be ulong, double or bool. The problem
is that for each line of text I'd like to apply all these
functions, collect the results and write them into some file.
For example,
[...]
As you can see, I created a templated Feature struct. This does
not help much because I also want to create an associative
array of ["functionName": ]. How can I
define such an array when "Feature!T function(string)[string]
allFuns" requires defining T beforehand and using auto is not
possible?
I was thinking of having a Feature struct with 3 fiels of
ulong, double and bool members but then each Feature init would
look ugly imho "Feature("name", null, 1.5, null)". There should
be a another way.
You can use an Algebraic [1] or SumType [2] for this:
alias Feature = SumType!(ulong, double, bool);
Feature numberOfPunctChars(string text)
{
// ...
return Feature(cnt);
}
Feature ratioOfDigitsToChars(string text)
{
// ...
return Feature(ratio);
}
Feature hasUnbalancedParens(string text)
{
// ...
return Feature(!isBalanced);
}
[1]
http://dpldocs.info/experimental-docs/std.variant.Algebraic.html
[2] https://code.dlang.org/packages/sumtype
Re: I need "windowsx.d" Someone can send It to me?
On Friday, 25 September 2020 at 15:03:56 UTC, Marcone wrote: I need windowsx.d but for I don't know the reason is not in dmd. Someone that have it can send to me? I don't know convert windowsx.h to windowsx.d https://wiki.dlang.org/Bindings#Binding_generators
Re: I need "windowsx.d" Someone can send It to me?
On Friday, 25 September 2020 at 15:03:56 UTC, Marcone wrote: I need windowsx.d but for I don't know the reason is not in dmd. Someone that have it can send to me? I don't know convert windowsx.h to windowsx.d You don't want to just include it? https://atilaoncode.blog/2018/04/09/include-c-headers-in-d-code/
Re: I need "windowsx.d" Someone can send It to me?
On Sunday, 27 September 2020 at 07:55:56 UTC, Imperatorn wrote: On Friday, 25 September 2020 at 15:03:56 UTC, Marcone wrote: I need windowsx.d but for I don't know the reason is not in dmd. Someone that have it can send to me? I don't know convert windowsx.h to windowsx.d You don't want to just include it? https://atilaoncode.blog/2018/04/09/include-c-headers-in-d-code/ Dpp is not able to translate macros (maybe in the future). Macros needs to be translated manually. Kind regards Andre
Re: Struct initializer in UDA
On Sunday, 27 September 2020 at 11:59:49 UTC, Anonymouse wrote:
On Sunday, 27 September 2020 at 10:17:39 UTC, realhet wrote:
On Saturday, 26 September 2020 at 17:13:17 UTC, Anonymouse
wrote:
On Saturday, 26 September 2020 at 16:05:58 UTC, realhet wrote:
That looks the closes to the python named parameters or the
struct initializer.
For my use case this opDispatch trick seems to be more flexible
than the named-parameters thing:
@(FieldProps().range(-360, 360).format("%.2f").caption("Turret
rotation").unit("deg")) float alpha = 0;
for example if I use the name: "logRange" it can also set the
isLogarithmic flag as a side effect to true inside the FieldProps
struct. Just by choosing a slightly different name.
With this idealized format it would be not possible:
@FieldProps{ range: {-360, 360}, format:"%.2f", caption:"Turret
rotation", unit:"deg"} float alpha = 0;
The more work inside the struct is not a problem, because I'm
willing to use it from 1000 places. Also __traits(allMembers) can
help.
Thank you!
Re: Methods for expanding class in another class/struct
On Saturday, 26 September 2020 at 11:30:23 UTC, k2aj wrote:
It does work, the problem is that scoped returns a Voldemort
type, so you have to use
typeof(scoped!SomeClass(someConstructorArgs)) to declare a
field. Gets really annoying when doing it with any class that
doesn't have a zero-argument constructor, especially in generic
code.
class Foo {}
class Bar {
typeof(scoped!Foo()) foo;
this() {
foo = scoped!Foo();
}
}
Thanks, so what we really need is a new scope template that
declares the the variables in the class and possible a template
for running the constructor?
Re: A scheduled control signal with fibers?
On 9/27/20 3:06 AM, Ferhat Kurtulmuş wrote:
> __gshared DList!Entry queue;
> __gshared bool shouldRun = true;
Have you considered passing messages with std.concurrency.send() and
std.concurrency.receive() and friends? You wouldn't need 'queue' because
all of your threads already have mail boxes to send messages to each other.
> void worker() {
> while(shouldRun){
> auto r = queue[];
> if(!r.empty && queue.back.st < Clock.currTime){
> writeln(queue.back); // consume the value
> sendPWMSignalToValfe(pwmval)
> queue.popLastOf(r);
> }
> }
> }
It's not clear whether it's only in your test code but busy-waiting like
that will make your CPU very warm. :) Since requests cannot pass each
other, your worker thread should have something like the following in
that loop:
import core.thread;
Thread.sleep(duration);
Depending on how accurate the operating system honors your sleep
requests (e.g. is it real-time?), you may want to sleep less than
'duration' and then busy-wait the rest of the duration. Similar to the
difference between spinForce() and yieldForce() of std.parallelism (I
understand that your solution should not involve std.parallelism):
https://dlang.org/phobos/std_parallelism.html#.Task.spinForce
As an improvement when defining durations, you don't need to "hide"
units in comments:
// enum afterNmilliseconds = 1500;
// Instead:
enum after = 1500.msecs;
msecs and friends are defined in core.time:
https://dlang.org/phobos/core_time.html#.dur
Ali
Re: Struct initializer in UDA
On Sunday, 27 September 2020 at 10:17:39 UTC, realhet wrote:
On Saturday, 26 September 2020 at 17:13:17 UTC, Anonymouse
wrote:
On Saturday, 26 September 2020 at 16:05:58 UTC, realhet wrote:
The closest I can get is @(S.init.c(9).f(42)) with use of
opDispatch, which is easier to read but still ugly.
All I can get is that the
- an identifier of a member is stronger than the opDispatch. ->
Error: function expected before (), not S(0, 0).c of type int
- and if I prefix it with '_' it ruins toString. -> Error: no
property toString for type onlineapp.S
import std.stdio, std.range, std.algorithm, std.traits,
std.meta, std.conv, std.string, std.uni, std.meta,
std.functional, std.exception;
struct S{
int a, b;
auto opDispatch(string name, T)(T value)
if(name.startsWith("_"))
{
mixin(name[1..$], "= value;");
return this;
}
}
void main(){
S.init._a(5).writeln;
}
Now I'm more confused, as the compiler completely ignores the
if(name.startsWith("_")) constraint o.O
It works if you specialise opDispatch to take an int parameter
instead of a type T. It smells like a bug but I don't know enough
to say.
I used two opDispatches to be able to avoid having to use _a and
_b, and std.algorithm.comparison.among to constrain them.
struct S{
private int _a, _b;
auto opDispatch(string name)(int value)
if (name.among("a", "b"))
{
mixin("_", name, "= value;");
return this;
}
auto opDispatch(string name)()
if (name.among("a", "b"))
{
mixin("return _", name, ";");
}
}
void main(){
S.init.a(123).b(456).writeln;
S().b(456).a(123).writeln; // Alternative syntax, may not
work if opCall is defined
}
It's brittle in that you have to update and sync the two
among("a", "b") constraints every time you add or remove a field,
but I can't seem to get the names by introspection without it
endlessly recursing over opDispatch again.
Re: A scheduled control signal with fibers?
On Sunday, 27 September 2020 at 10:40:25 UTC, Ali Çehreli wrote:
On 9/27/20 3:06 AM, Ferhat Kurtulmuş wrote:
> __gshared DList!Entry queue;
> __gshared bool shouldRun = true;
Have you considered passing messages with
std.concurrency.send() and std.concurrency.receive() and
friends? You wouldn't need 'queue' because all of your threads
already have mail boxes to send messages to each other.
> void worker() {
> while(shouldRun){
> auto r = queue[];
> if(!r.empty && queue.back.st < Clock.currTime){
> writeln(queue.back); // consume the value
> sendPWMSignalToValfe(pwmval)
> queue.popLastOf(r);
> }
> }
> }
It's not clear whether it's only in your test code but
busy-waiting like that will make your CPU very warm. :) Since
requests cannot pass each other, your worker thread should have
something like the following in that loop:
import core.thread;
Thread.sleep(duration);
Depending on how accurate the operating system honors your
sleep requests (e.g. is it real-time?), you may want to sleep
less than 'duration' and then busy-wait the rest of the
duration. Similar to the difference between spinForce() and
yieldForce() of std.parallelism (I understand that your
solution should not involve std.parallelism):
https://dlang.org/phobos/std_parallelism.html#.Task.spinForce
As an improvement when defining durations, you don't need to
"hide" units in comments:
// enum afterNmilliseconds = 1500;
// Instead:
enum after = 1500.msecs;
msecs and friends are defined in core.time:
https://dlang.org/phobos/core_time.html#.dur
Ali
Yes, this solution requires less code and obviously less system
resources.
void main() {
while (true) {
int v;
"type your value: ".write;
readf(" %d", );
if(v==0){
break;
}
auto childTid = spawn(, thisTid);
send(childTid, v);
}
writeln("main is done.");
}
static void spawnedFunc(Tid ownerTid)
{
receive((int v){
Thread.sleep(1500.msecs);
writeln(v);
});
}
However, there is a big problem now. If I change my main like
below, numbers are not written at the correct order after 1.5
seconds?
void main() {
foreach (v; 0..10){
auto childTid = spawn(, thisTid);
send(childTid, v);
}
writeln("main is done.");
}
Re: A scheduled control signal with fibers?
On Friday, 25 September 2020 at 13:37:09 UTC, Steven
Schveighoffer wrote:
Given the rate and the number of concurrent tasks, I'd say
threads.
-Steve
Here is my testable and minimal code using 1 extra thread. Thank
you all!
import core.thread;
import std.stdio;
import std.concurrency;
import std.container.dlist;
import std.datetime;
import std.datetime.systime;
__gshared DList!Entry queue;
__gshared bool shouldRun = true;
struct Entry {
SysTime st;
int val;
}
void main() {
spawn();
while (true) {
int v;
"enter your value: ".write; //
getFlameIntensityViaImageProcessing()
readf(" %d", );
if(v==0){
shouldRun = false;
break;
}
queue.insertFront(Entry(Clock.currTime + 1500.msecs, v));
}
writeln("main is done.");
}
void worker() {
while(shouldRun){
auto r = queue[];
if(!r.empty && queue.back.st < Clock.currTime){
writeln(queue.back); // consume the value
sendPWMSignalToValfe(pwmval)
queue.popLastOf(r);
}
}
}
Re: Struct initializer in UDA
On Saturday, 26 September 2020 at 17:13:17 UTC, Anonymouse wrote:
On Saturday, 26 September 2020 at 16:05:58 UTC, realhet wrote:
The closest I can get is @(S.init.c(9).f(42)) with use of
opDispatch, which is easier to read but still ugly.
All I can get is that the
- an identifier of a member is stronger than the opDispatch. ->
Error: function expected before (), not S(0, 0).c of type int
- and if I prefix it with '_' it ruins toString. -> Error: no
property toString for type onlineapp.S
import std.stdio, std.range, std.algorithm, std.traits, std.meta,
std.conv, std.string, std.uni, std.meta, std.functional,
std.exception;
struct S{
int a, b;
auto opDispatch(string name, T)(T value)
if(name.startsWith("_"))
{
mixin(name[1..$], "= value;");
return this;
}
}
void main(){
S.init._a(5).writeln;
}
Now I'm more confused, as the compiler completely ignores the
if(name.startsWith("_")) constraint o.O
Re: A scheduled control signal with fibers?
On Sunday, 27 September 2020 at 10:40:25 UTC, Ali Çehreli wrote: On 9/27/20 3:06 AM, Ferhat Kurtulmuş wrote: Have you considered passing messages with std.concurrency.send() and std.concurrency.receive() and friends? You wouldn't need 'queue' because all of your threads already have mail boxes to send messages to each other. I remember that your book covers passing messages with send(). Probably I will rewrite it using that mechanism, you are right, I noticed that when I run the code I can hear the boosted noise of my desktop fan. As an improvement when defining durations, you don't need to "hide" units in comments: // enum afterNmilliseconds = 1500; // Instead: enum after = 1500.msecs; msecs and friends are defined in core.time: https://dlang.org/phobos/core_time.html#.dur Thank you for the tip. That was just a preudo-code to explain my situation. Thanks a lot. Ferhat
Re: A scheduled control signal with fibers?
On Sunday, 27 September 2020 at 10:52:58 UTC, Ferhat Kurtulmuş wrote: On Sunday, 27 September 2020 at 10:40:25 UTC, Ali Çehreli wrote: [...] [...] I remember that your book covers passing messages with send(). Probably I will rewrite it using that mechanism, you are right, I noticed that when I run the code I can hear the boosted noise of my desktop fan. [...] Thank you for the tip. That was just a preudo-code to explain my situation. Thanks a lot. Ferhat The actor model is under-rated imho
Re: I need "windowsx.d" Someone can send It to me?
On Friday, 25 September 2020 at 15:03:56 UTC, Marcone wrote: I need windowsx.d but for I don't know the reason is not in dmd. Someone that have it can send to me? I don't know convert windowsx.h to windowsx.d Maybe it is already available on code.dlang.org?
Safe to remove AA elements while iterating over it via .byKeyValue?
Is it safe to remove AA-elements from an `aa` I'm iterating over
via aa.byKeyValue?
I'm currently doing this:
foreach (ref kv; aa.byKeyValue)
{
if (pred(kv.key))
aa.remove(kv.key); // ok?
}
if (aa.length == 0)
aa = null;
Is there a better way?
Re: A scheduled control signal with fibers?
On 9/27/20 6:33 AM, Ferhat Kurtulmuş wrote:
> On Sunday, 27 September 2020 at 12:05:13 UTC, Ferhat Kurtulmuş wrote:
>> On Sunday, 27 September 2020 at 10:40:25 UTC, Ali Çehreli wrote:
>>> On 9/27/20 3:06 AM, Ferhat Kurtulmuş wrote:
>
> Oh, It will work fine if I imitate my time-consuming image processing
> like this.
> I think it is Ok now.
>
> import std.stdio;
> import std.concurrency;
> import core.thread;
>
> void main() {
> foreach (v; 0..10){
> auto childTid = spawn(, thisTid);
How many flame threads do you need? I thought one image processor and
one flame thrower, no? Even if you have a dozen of each, main can start
only the image processing threads and then each image processor can
start its own flame thrower. Then, each pair will have an owner and a
worker.
You don't need to send thisTid because every thread already has an
ownerTid defined:
auto childTid = spawn();
> Thread.sleep(10.msecs); // imitate image processing
> send(childTid, v);
UFCS makes it nicer:
childTid.send(v);
>
> }
> writeln("main is done.");
> }
>
> static void spawnedFunc(Tid ownerTid)
To repeat, you already have a valid ownerTid in this thread. Just remove
the parameter.
> {
> receive((int v){
> Thread.sleep(1500.msecs);
I think you should sleep less than that to work at the exact expected
time. Otherwise, an unknown amount of time has already passed when this
thread is woken up again.
Instead of sleeping 1500, something like this may be needed:
- This thread looks at the time to figure out how long to sleep e.g.
sometimes 1400 msecs
- Sleeps that amount
- Fires when it wakes up
However, you can not expect to be waken up exactly at 1400 msecs later.
If timing precision is really important, I recommend running some
statistics to see how much off your thread is when it wakes up.
Depending on the statistics, I would sleep less than the expected amount
and then burn the CPU until it's the exact time. But maybe precision is
not that important; so, forget that idea. :)
> writeln(v);
> });
> }
One more thing: It is common for the workers to die with an exception
(sometimes with Error). You must catch it (including Error) by the
worker thread and report it somehow e.g. with a special exception.
Otherwise, nobody will know what happened.
This reminds me: If you start the worker with spawnLinked() instead of
spawn(), the owner will get a LinkTerminated message if a thread dies.
That's another way of detecting that failure.
Ali
Array Slicing
Are these in the Specification or Phobos? I figured them out a
few days ago. These are from my snippet journal on arrays and
there may be more.
void main()
{
int[5] a = [1, 2, 3, 4, 5];
int[5][3] b = [[6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16,
17, 18, 19, 20]];
int[5] c;
// This:
writeln(a[1..4][0]);
writeln(b[0][1..4]);
writeln(b[1][1..4][2]);
//writeln(b[0..1][1..3]); // Range violation.
//writeln(a[$-2..$-3]); // NG.
writeln(a[$-3..$-2])
// And, this:
c[0..5] = a[0..$-0]
writeln(c);
}
My apologizes, if any if these are noted or wrong.
Re: Safe to remove AA elements while iterating over it via .byKeyValue?
On Sunday, 27 September 2020 at 13:02:04 UTC, Per Nordlöw wrote:
Is it safe to remove AA-elements from an `aa` I'm iterating
over via aa.byKeyValue?
I'm currently doing this:
foreach (ref kv; aa.byKeyValue)
{
if (pred(kv.key))
aa.remove(kv.key); // ok?
}
if (aa.length == 0)
aa = null;
Is there a better way?
What you could do is find all matches (pred) and remove range of
indices
Re: Safe to remove AA elements while iterating over it via .byKeyValue?
On Sun, Sep 27, 2020 at 01:02:04PM +, Per Nordlöw via Digitalmars-d-learn wrote: > Is it safe to remove AA-elements from an `aa` I'm iterating over via > aa.byKeyValue? No. Modifying a container while iterating over it is, in general, a bad idea (unless the container is designed to be used that way, but even then, such removal is generally restricted), because it often leads to highly counterintuitive results. In the case of AA's, removing an element may lead to a rehashing, which reorders elements, and your iteration may miss some elements or repeat some elements or terminate prematurely. Even without a rehashing, you may encounter inconsistent behaviours, like some elements going "missing". You probably want to build a list of keys to remove, then remove them after the iteration instead. T -- Why can't you just be a nonconformist like everyone else? -- YHL
Re: Array Slicing
On Sun, Sep 27, 2020 at 01:59:07PM +, DMon via Digitalmars-d-learn wrote: > Are these in the Specification or Phobos? See: https://dlang.org/articles/d-array-article.html T -- Государство делает вид, что платит нам зарплату, а мы делаем вид, что работаем.
Re: Safe to remove AA elements while iterating over it via .byKeyValue?
On Sunday, 27 September 2020 at 13:02:04 UTC, Per Nordlöw wrote:
Is it safe to remove AA-elements from an `aa` I'm iterating
over via aa.byKeyValue?
I'm currently doing this:
foreach (ref kv; aa.byKeyValue)
{
if (pred(kv.key))
aa.remove(kv.key); // ok?
}
if (aa.length == 0)
aa = null;
Is there a better way?
Normally this is not advisable since you're modifying the
iterated source.
Same thing in C#, there it's a compiler error.
Re: A scheduled control signal with fibers?
On Sunday, 27 September 2020 at 12:05:13 UTC, Ferhat Kurtulmuş
wrote:
On Sunday, 27 September 2020 at 10:40:25 UTC, Ali Çehreli wrote:
On 9/27/20 3:06 AM, Ferhat Kurtulmuş wrote:
Oh, It will work fine if I imitate my time-consuming image
processing like this.
I think it is Ok now.
import std.stdio;
import std.concurrency;
import core.thread;
void main() {
foreach (v; 0..10){
auto childTid = spawn(, thisTid);
Thread.sleep(10.msecs); // imitate image processing
send(childTid, v);
}
writeln("main is done.");
}
static void spawnedFunc(Tid ownerTid)
{
receive((int v){
Thread.sleep(1500.msecs);
writeln(v);
});
}
Re: Safe to remove AA elements while iterating over it via .byKeyValue?
On Sunday, 27 September 2020 at 13:02:04 UTC, Per Nordlöw wrote:
Is it safe to remove AA-elements from an `aa` I'm iterating
over via aa.byKeyValue?
I'm currently doing this:
foreach (ref kv; aa.byKeyValue)
{
if (pred(kv.key))
aa.remove(kv.key); // ok?
}
if (aa.length == 0)
aa = null;
Is there a better way?
The boring way is to store an array of the spent keys and remove
afterwards.
KeyType!(typeof(aa))[] garbage;
garbage.reserve(aa.length);
foreach (ref kv; aa.byKeyValue)
{
if (pred(kv.key))
garbage ~= kv.key;
}
foreach (const key; garbage)
{
aa.remove(key);
}
This works with normal arrays too (and
std.algorithm.mutation.remove), if you foreach_reverse the
garbage array.
