Re: Template-style polymorphism in table structure
On Monday, 5 September 2016 at 06:45:07 UTC, data pulverizer
wrote:
On Sunday, 4 September 2016 at 14:49:30 UTC, Lodovico Giaretta
wrote:
Your getCol(i) could become getCol!T(i) and return an instance
of GenericVector!T directly, after checking that the required
column has in fact that type:
GenericVector!T getCol!T(size_t i)
{
if(typeid(cols[i]) == typeid(GenericVector!T))
return cast(GenericVector!T)cols[i];
else
// assert(0) or throw exception
}
I just realized that typeid only gives the class and not the
actual type, so the object will still need to be cast as you
mentioned above, however your above function will not infer T,
so the user will have to provide it. I wonder if there is a way
to dispatch the right type by a dynamic cast or I fear that
ZombineDev may be correct and the types will have to be
limited, which I definitely want to avoid!
Just found this on dynamic dispatching
(https://wiki.dlang.org/Dispatching_an_object_based_on_its_dynamic_type) but even if you took this approach, you'd still have to register all the types you would be using at the start of the script for all your methods. It's either that or explicitly limited type list as ZombineDev suggests.
Re: Template-style polymorphism in table structure
On Monday, 5 September 2016 at 06:45:07 UTC, data pulverizer
wrote:
On Sunday, 4 September 2016 at 14:49:30 UTC, Lodovico Giaretta
wrote:
Your getCol(i) could become getCol!T(i) and return an instance
of GenericVector!T directly, after checking that the required
column has in fact that type:
GenericVector!T getCol!T(size_t i)
{
if(typeid(cols[i]) == typeid(GenericVector!T))
return cast(GenericVector!T)cols[i];
else
// assert(0) or throw exception
}
I just realized that typeid only gives the class and not the
actual type, so the object will still need to be cast as you
mentioned above, however your above function will not infer T,
so the user will have to provide it. I wonder if there is a way
to dispatch the right type by a dynamic cast or I fear that
ZombineDev may be correct and the types will have to be
limited, which I definitely want to avoid!
ZombineDev is definitely correct, in that one thing is the static
type, and another thing is the dynamic type. The type of a
variable, or the return type of a method are based on the static
type, computed at compile time. The "true" dynamic type is only
available at runtime.
That's why I was showing you the use of tuples. If your code does
not have branches that assign different column types, having the
types statically determined as template parameters is the best
choice.
If you really need dynamic types, then there's no alternative:
the user must explicitly cast things to the correct dynamic type
(my version of getCol is just a nice wrapper to do that). In
fact, idiomatic D code tries to avoid dynamic types when
possible, preferring templates.
How it's better to store data from DB?
Usually I am storing daba from DB as array of structures.
Something like:
struct MyData
{
int id;
string name;
int age;
}
MyData mydata;
Then I am creating array of structures:
MyData [] mydatas;
And fill data in my code. Then append it to `mydatas` to get it
iterable.
But is it's good? Maybe there there is better way?
I need main -- be able iterate thru the data. Any other variants?
Re: How it's better to store data from DB?
On Monday, 5 September 2016 at 10:00:26 UTC, Suliman wrote:
Usually I am storing daba from DB as array of structures.
Something like:
struct MyData
{
int id;
string name;
int age;
}
MyData mydata;
Then I am creating array of structures:
MyData [] mydatas;
And fill data in my code. Then append it to `mydatas` to get it
iterable.
But is it's good? Maybe there there is better way?
I need main -- be able iterate thru the data. Any other
variants?
It depends on your specific use case. My advice is to try *not*
to store the data in memory.
I mean, if your first operation on the array is to filter it (but
that should be done directly in the sql queries) or if you manage
to do everything while iterating it only once, then you can avoid
creating the array. Create a range that wraps the query result
set and iterate it. This way you maintain in memory just one
element at a time. This is akin to what you usually do in JDBC (I
used that a lot, while in D I don't have any db experience).
But of course there are cases in which this advice is not
applicable.
Re: Using OpenGL
On Monday, 5 September 2016 at 05:14:56 UTC, Nicholas Wilson wrote: On Saturday, 3 September 2016 at 17:13:49 UTC, Darren wrote: Now I wonder if I can load shaders from separate files (à la http://www.opengl-tutorial.org/beginners-tutorials/tutorial-2-the-first-triangle/). see: https://p0nce.github.io/d-idioms/#Embed-a-dynamic-library-in-an-executable for `import`ing external files at compile time. It's often useful to be able to reload shaders at runtime.
Custom String vs D String performance
I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac
Re: Custom String vs D String performance
Dne 5.9.2016 v 13:11 Patric via Digitalmars-d-learn napsal(a): I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac One of reason could be GC, because I belive in D string it reuse memory, but in your case you always do malloc
Re: Custom String vs D String performance
Dne 5.9.2016 v 13:17 Daniel Kozak napsal(a): Dne 5.9.2016 v 13:11 Patric via Digitalmars-d-learn napsal(a): I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac One of reason could be GC, because I belive in D string it reuse memory, but in your case you always do malloc BTW on my pc your Custom String is faster than D string
Re: Custom String vs D String performance
On 05/09/2016 11:11 PM, Patric wrote: I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac Ok lots of bad assumptions in there so lets declare what they should be: 1. D supports three string types, string, wstring and dstring with the character types of char, wchar and dchar. Strings themselves have no special behavior in the compiler as they are arrays. 2. Types such as char are fixed in size, no point multiplying when its a constant 1. 3. A D string is length then pointer. Ok, now on to implementation do not use StopWatch for benchmarking. Use benchmark[0]. This will execute the benchmark many times which removes one off errors. Don't directly call malloc, it will never be free'd in this case. ``new char(length)`` would be better as it will automatically be handled by the GC. You'll also want to reserve a block of memory to remove allocation from the cost as much as possible (after all you're not measuring that are you?). Don't forget to disable the GC as well so it doesn't try to collect during the tests. [0] https://dlang.org/phobos/std_datetime.html#.benchmark [1] http://dlang.org/spec/type.html [2] http://dlang.org/spec/abi.html [3] https://github.com/dlang/druntime/blob/master/src/object.d#L41
Re: Custom String vs D String performance
On Monday, 5 September 2016 at 11:11:23 UTC, Patric wrote:
I´m playing remaking D functionalities with nogc structs, and
to at least match D performance.
But in this particular case i´m unable to get near D
performance.
Can someone point me out what i´m doing wrong, or if there is
some magic behind the curtains on D strings?
https://dpaste.dzfl.pl/1c981fdc71ac
string s;
string a = "testing";
string b = "another";
foreach(_ ; 0..max){
s = a ~ b;
}
Potentially this makes no allocation at all. "testing" and
"another" will be in readonly memory, "a ~ b" will be
constant-folded, and s will get assigned the same slice
every-time.
Now replace it with std::string in C++ and count the number of
malloc ;)
Re: Custom String vs D String performance
Dne 5.9.2016 v 13:20 rikki cattermole via Digitalmars-d-learn napsal(a): ... Don't forget to disable the GC as well so it doesn't try to collect during the tests. This is not true, in many cases it will hurt performance a lot
Re: Custom String vs D String performance
On Monday, 5 September 2016 at 11:20:08 UTC, rikki cattermole wrote: On 05/09/2016 11:11 PM, Patric wrote: I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac Ok lots of bad assumptions in there so lets declare what they should be: 1. D supports three string types, string, wstring and dstring with the character types of char, wchar and dchar. Strings themselves have no special behavior in the compiler as they are arrays. 2. Types such as char are fixed in size, no point multiplying when its a constant 1. 3. A D string is length then pointer. Ok, now on to implementation do not use StopWatch for benchmarking. Use benchmark[0]. This will execute the benchmark many times which removes one off errors. Don't directly call malloc, it will never be free'd in this case. ``new char(length)`` would be better as it will automatically be handled by the GC. You'll also want to reserve a block of memory to remove allocation from the cost as much as possible (after all you're not measuring that are you?). Don't forget to disable the GC as well so it doesn't try to collect during the tests. [0] https://dlang.org/phobos/std_datetime.html#.benchmark [1] http://dlang.org/spec/type.html [2] http://dlang.org/spec/abi.html [3] https://github.com/dlang/druntime/blob/master/src/object.d#L41 I´m aware of 1, and 2. I look one million times on datetime and did´nt see the benchmark, thanks xD My intention is to not use gc at all, so no "new" for me. Yes the optimal case will be reserve the memory beforehand, but i´m benchmarking the opBinary. So now a bit better example :) https://dpaste.dzfl.pl/b9356f57a8c8 Daniel Kozak: Ok, now it gets a bit weird. On DPaste it shows: 14 ms and 343 μs - DString 3 ms and 928 μs - CustomString And on my PC (with dub release mode) : 7 ms, 885 μs, and 9 hnsecs - DString 18 ms, 740 μs, and 8 hnsecs - CustomString (!!!)
Re: Custom String vs D String performance
Dne 5.9.2016 v 13:45 Patric via Digitalmars-d-learn napsal(a): On Monday, 5 September 2016 at 11:20:08 UTC, rikki cattermole wrote: On 05/09/2016 11:11 PM, Patric wrote: I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac Ok lots of bad assumptions in there so lets declare what they should be: 1. D supports three string types, string, wstring and dstring with the character types of char, wchar and dchar. Strings themselves have no special behavior in the compiler as they are arrays. 2. Types such as char are fixed in size, no point multiplying when its a constant 1. 3. A D string is length then pointer. Ok, now on to implementation do not use StopWatch for benchmarking. Use benchmark[0]. This will execute the benchmark many times which removes one off errors. Don't directly call malloc, it will never be free'd in this case. ``new char(length)`` would be better as it will automatically be handled by the GC. You'll also want to reserve a block of memory to remove allocation from the cost as much as possible (after all you're not measuring that are you?). Don't forget to disable the GC as well so it doesn't try to collect during the tests. [0] https://dlang.org/phobos/std_datetime.html#.benchmark [1] http://dlang.org/spec/type.html [2] http://dlang.org/spec/abi.html [3] https://github.com/dlang/druntime/blob/master/src/object.d#L41 I´m aware of 1, and 2. I look one million times on datetime and did´nt see the benchmark, thanks xD My intention is to not use gc at all, so no "new" for me. Yes the optimal case will be reserve the memory beforehand, but i´m benchmarking the opBinary. So now a bit better example :) https://dpaste.dzfl.pl/b9356f57a8c8 Daniel Kozak: Ok, now it gets a bit weird. On DPaste it shows: 14 ms and 343 μs - DString 3 ms and 928 μs - CustomString And on my PC (with dub release mode) : 7 ms, 885 μs, and 9 hnsecs - DString 18 ms, 740 μs, and 8 hnsecs - CustomString (!!!) Do you have windows or linux? Which version of dmd you have?
Re: Custom String vs D String performance
On 05/09/2016 11:45 PM, Patric wrote: On Monday, 5 September 2016 at 11:20:08 UTC, rikki cattermole wrote: On 05/09/2016 11:11 PM, Patric wrote: I´m playing remaking D functionalities with nogc structs, and to at least match D performance. But in this particular case i´m unable to get near D performance. Can someone point me out what i´m doing wrong, or if there is some magic behind the curtains on D strings? https://dpaste.dzfl.pl/1c981fdc71ac Ok lots of bad assumptions in there so lets declare what they should be: 1. D supports three string types, string, wstring and dstring with the character types of char, wchar and dchar. Strings themselves have no special behavior in the compiler as they are arrays. 2. Types such as char are fixed in size, no point multiplying when its a constant 1. 3. A D string is length then pointer. Ok, now on to implementation do not use StopWatch for benchmarking. Use benchmark[0]. This will execute the benchmark many times which removes one off errors. Don't directly call malloc, it will never be free'd in this case. ``new char(length)`` would be better as it will automatically be handled by the GC. You'll also want to reserve a block of memory to remove allocation from the cost as much as possible (after all you're not measuring that are you?). Don't forget to disable the GC as well so it doesn't try to collect during the tests. [0] https://dlang.org/phobos/std_datetime.html#.benchmark [1] http://dlang.org/spec/type.html [2] http://dlang.org/spec/abi.html [3] https://github.com/dlang/druntime/blob/master/src/object.d#L41 I´m aware of 1, and 2. I look one million times on datetime and did´nt see the benchmark, thanks xD My intention is to not use gc at all, so no "new" for me. Yes the optimal case will be reserve the memory beforehand, but i´m benchmarking the opBinary. So now a bit better example :) https://dpaste.dzfl.pl/b9356f57a8c8 Daniel Kozak: Ok, now it gets a bit weird. On DPaste it shows: 14 ms and 343 μs - DString 3 ms and 928 μs - CustomString And on my PC (with dub release mode) : 7 ms, 885 μs, and 9 hnsecs - DString 18 ms, 740 μs, and 8 hnsecs - CustomString (!!!) Be a bit careful there, when a struct is moved around its destructor will be called. This is why I suggested you to use the GC to allocate memory or else ouch. So you'll find very quickly that you will be having segfaults since you will be doing use after free. Oh and you'll want to turn that into a slice at some point ``char[] str = ptr[0 .. length];``.
Re: Custom String vs D String performance
On Monday, 5 September 2016 at 11:53:12 UTC, Daniel Kozak wrote: Do you have windows or linux? Which version of dmd you have? Now on my job pc: DMD32 D Compiler v2.071.0-b2 In home i have 64 last version, and with my first version it shows the DString faster than my custom.
Re: Custom String vs D String performance
On Monday, 5 September 2016 at 11:55:09 UTC, rikki cattermole wrote: Be a bit careful there, when a struct is moved around its destructor will be called. This is why I suggested you to use the GC to allocate memory or else ouch. So you'll find very quickly that you will be having segfaults since you will be doing use after free. Iep, the full code have the postblit operator to correct this :)
Re: Custom String vs D String performance
On Monday, 5 September 2016 at 12:03:49 UTC, Patric wrote: On Monday, 5 September 2016 at 11:53:12 UTC, Daniel Kozak wrote: Do you have windows or linux? Which version of dmd you have? Now on my job pc: DMD32 D Compiler v2.071.0-b2 In home i have 64 last version, and with my first version it shows the DString faster than my custom. Well, if my opBinary implementation is right (in the performance sense also), so is a matter of Platform not of implementation, and i´m ok with that :) But I find strange this kind of discrepancy.
delegates, lambdas and functions pitfall
I am about to write my own stupid and simple http client .. and i
have added a callback function that has the received content as a
parameter.
class AsyncHttpGet
{
this(string host, ushort port, string path, void
delegate(string) callback )
{ ... }
}
My first attempt was to write:
auto f = new AsyncHttpGet("www.dprogramming.com", 80,
"/index.php", (string content) => {
...
});
but this is does not work because my AsyncHttpGet takes a normal
delegate and this => seems to add nothrow @nogc @safe to my
delegate type.
The correct syntax is only marginally differnt, but took me quite
a while to figure out:
( the missing arrow )
auto f = new AsyncHttpGet("www.dprogramming.com", 80,
"/index.php", (string content)
{
... // this is of type function
});
i noticed that delegates are "more powerful" than functions. once
the passed function e.g. needs to capture a value from the
outside it becomes a delegate type. I have also read that a
delegate can contain a reference to a class method bound to an
instance.
int dummy = 0;
auto f = new AsyncHttpGet("www.dprogramming.com", 80,
"/index.php", (string content)
{
dummy = 1; // this is of type delegate
});
but what is the difference between a lambda (=>) and a
functions/delegates?
i think this is a major pitfall for newcomers, and should be
adressed somehow.
Re: delegates, lambdas and functions pitfall
Dne 5.9.2016 v 14:15 dom via Digitalmars-d-learn napsal(a):
I am about to write my own stupid and simple http client .. and i have
added a callback function that has the received content as a parameter.
class AsyncHttpGet
{
this(string host, ushort port, string path, void delegate(string)
callback )
{ ... }
}
My first attempt was to write:
auto f = new AsyncHttpGet("www.dprogramming.com", 80, "/index.php",
(string content) => {
...
});
but this is does not work because my AsyncHttpGet takes a normal
delegate and this => seems to add nothrow @nogc @safe to my delegate
type.
The correct syntax is only marginally differnt, but took me quite a
while to figure out:
( the missing arrow )
auto f = new AsyncHttpGet("www.dprogramming.com", 80, "/index.php",
(string content)
{
... // this is of type function
});
i noticed that delegates are "more powerful" than functions. once the
passed function e.g. needs to capture a value from the outside it
becomes a delegate type. I have also read that a delegate can contain
a reference to a class method bound to an instance.
int dummy = 0;
auto f = new AsyncHttpGet("www.dprogramming.com", 80, "/index.php",
(string content)
{
dummy = 1; // this is of type delegate
});
but what is the difference between a lambda (=>) and a
functions/delegates?
i think this is a major pitfall for newcomers, and should be adressed
somehow.
(string content) => { } // this is delegate which returns another
delegates {} is shorthand here for (){}
when you use => syntax you can just return expression
(string content) => content; is same as (string content) { return content; }
Re: delegates, lambdas and functions pitfall
Dne 5.9.2016 v 14:15 dom via Digitalmars-d-learn napsal(a): ... but what is the difference between a lambda (=>) and a functions/delegates? i think this is a major pitfall for newcomers, and should be adressed somehow. Yes, RTFM :)
Re: delegates, lambdas and functions pitfall
Dne 5.9.2016 v 14:30 Daniel Kozak napsal(a): Dne 5.9.2016 v 14:15 dom via Digitalmars-d-learn napsal(a): ... but what is the difference between a lambda (=>) and a functions/delegates? i think this is a major pitfall for newcomers, and should be adressed somehow. Yes, RTFM :) But to be fair I have made this mistake myself many times :)
Re: delegates, lambdas and functions pitfall
On Monday, 5 September 2016 at 12:15:35 UTC, dom wrote:
[...]
You misunderstood the error message and the lambda syntax (it
also happened to me the first time).
The grammar says that you can use one of these syntaxes:
1) `(arguments) {block of code}`
2) `(arguments) => expression`, which is equivalent to
`(arguments) {return expression;}`
3) `{block of code}`, which is equivalent to `(){block of code}`.
So if you write `(arguments) => {block of code}`, this is
equivalent to (see rule 2) `(arguments) { return {block of code};
}`.
And because of rule 3, it becomes `(arguments) { return (){block
of code} }`. So what you have is a function that returns a
function. That's why it does not match your signature.
The fact that the compiler also adds nothrow, @nogc, @safe is not
important in this case, as those attributes can be implicitly
casted away.
Assign any event kind to a single templatized function ?
It's almost a "yeah". However this doesn't work with ref
parameters. Any idea how to make this work, keeping the
simplicity of the concept ?
°°
module runnable;
import std.stdio;
struct Foo
{
void delegate(int) event1;
void delegate(int,int) event2;
void delegate(int,ref int) event3;
}
struct Handler
{
void handle(A...)(A a){writeln(a);}
void handleref(A...)(/*auto ref*/ A a){writeln(a);}
}
void main(string[] args)
{
import std.traits;
Foo foo;
Handler handler;
foo.event1 = &handler.handle!(Parameters!(foo.event1));
foo.event2 = &handler.handle!(Parameters!(foo.event2));
foo.event3 = &handler.handleref!(Parameters!(foo.event2)); //
?
}
°°
Re: Assign any event kind to a single templatized function ?
On Monday, 5 September 2016 at 13:44:53 UTC, Basile B. wrote: Typo, last line should be: foo.event3 = &handler.handleref!(Parameters!(foo.event3)); But it still doesnt work.
Re: Assign any event kind to a single templatized function ?
On 09/05/2016 03:44 PM, Basile B. wrote:
°°
module runnable;
import std.stdio;
struct Foo
{
void delegate(int) event1;
void delegate(int,int) event2;
void delegate(int,ref int) event3;
}
struct Handler
{
void handle(A...)(A a){writeln(a);}
void handleref(A...)(/*auto ref*/ A a){writeln(a);}
}
void main(string[] args)
{
import std.traits;
Foo foo;
Handler handler;
foo.event1 = &handler.handle!(Parameters!(foo.event1));
foo.event2 = &handler.handle!(Parameters!(foo.event2));
foo.event3 = &handler.handleref!(Parameters!(foo.event2)); // ?
}
°°
You can pass the delegate type itself by alias. Then Parameters carries
over the ref. Not sure if that's well-defined or if it just happens to work.
void handlef(F)(Parameters!F a){writeln(a);}
...
foo.event3 = &handler.handlef!(typeof(foo.event3));
Re: Assign any event kind to a single templatized function ?
On 09/05/2016 04:00 PM, ag0aep6g wrote:
You can pass the delegate type itself by alias.
[...]
void handlef(F)(Parameters!F a){writeln(a);}
Don't know why I wrote "by alias". Clearly no alias there.
Re: Assign any event kind to a single templatized function ?
On Monday, 5 September 2016 at 14:00:04 UTC, ag0aep6g wrote:
On 09/05/2016 03:44 PM, Basile B. wrote:
[...]
You can pass the delegate type itself by alias. Then Parameters
carries over the ref. Not sure if that's well-defined or if it
just happens to work.
void handlef(F)(Parameters!F a){writeln(a);}
...
foo.event3 = &handler.handlef!(typeof(foo.event3));
Nice !
Getting the superclass of a type?
I'd like to be able to write something like this, but I haven't
been able to find anything in the docs
class Base{}
class Sub: Base{}
static assert(is(SuperClassOf!Sub == Base));
Re: Getting the superclass of a type?
On Monday, 5 September 2016 at 15:20:10 UTC, pineapple wrote:
I'd like to be able to write something like this, but I haven't
been able to find anything in the docs
class Base{}
class Sub: Base{}
static assert(is(SuperClassOf!Sub == Base));
https://dlang.org/phobos/std_traits.html#.BaseClassesTuple
Removing array element in foreach, safe?
is this code safe? if not how do i do it correctly?
static AsyncHttpGet[] openRequests;
static void updateRequests()
{
foreach(idx, req; openRequests)
{
if(req.state != Fiber.State.TERM)
req.call();
else
openRequests.remove(idx);
}
}
thx :)
Re: Getting the superclass of a type?
Am 05.09.2016 um 17:43 schrieb Lodovico Giaretta:
> On Monday, 5 September 2016 at 15:20:10 UTC, pineapple wrote:
>> I'd like to be able to write something like this, but I haven't been
>> able to find anything in the docs
>>
>> class Base{}
>> class Sub: Base{}
>> static assert(is(SuperClassOf!Sub == Base));
>
> https://dlang.org/phobos/std_traits.html#.BaseClassesTuple
Another option would be to use the following:
class Base {}
class Sub: Base {}
class Other {}
static assert(is(Sub : Base));
static assert(!is(Other : Base));
However, the ":" syntax also works for automatic conversion (see
http://ddili.org/ders/d.en/is_expr.html and search for "is (T : OtherT)").
Re: delegates, lambdas and functions pitfall
On Monday, 5 September 2016 at 12:30:37 UTC, Daniel Kozak wrote: Dne 5.9.2016 v 14:15 dom via Digitalmars-d-learn napsal(a): ... but what is the difference between a lambda (=>) and a functions/delegates? i think this is a major pitfall for newcomers, and should be adressed somehow. Yes, RTFM :) yes you are right, but laziness you know :D those pages aren't especially beginner friendly x) https://dlang.org/spec/expression.html#Lambda
Re: delegates, lambdas and functions pitfall
On Monday, 5 September 2016 at 12:32:49 UTC, Lodovico Giaretta
wrote:
On Monday, 5 September 2016 at 12:15:35 UTC, dom wrote:
[...]
You misunderstood the error message and the lambda syntax (it
also happened to me the first time).
The grammar says that you can use one of these syntaxes:
1) `(arguments) {block of code}`
2) `(arguments) => expression`, which is equivalent to
`(arguments) {return expression;}`
3) `{block of code}`, which is equivalent to `(){block of
code}`.
So if you write `(arguments) => {block of code}`, this is
equivalent to (see rule 2) `(arguments) { return {block of
code}; }`.
And because of rule 3, it becomes `(arguments) { return
(){block of code} }`. So what you have is a function that
returns a function. That's why it does not match your signature.
The fact that the compiler also adds nothrow, @nogc, @safe is
not important in this case, as those attributes can be
implicitly casted away.
thank you for that detailed answer.
Re: Getting the superclass of a type?
On Monday, 5 September 2016 at 15:43:52 UTC, Lodovico Giaretta
wrote:
On Monday, 5 September 2016 at 15:20:10 UTC, pineapple wrote:
I'd like to be able to write something like this, but I
haven't been able to find anything in the docs
class Base{}
class Sub: Base{}
static assert(is(SuperClassOf!Sub == Base));
https://dlang.org/phobos/std_traits.html#.BaseClassesTuple
Aha, thank you!
Re: Unicode function name? ∩
On Monday, 29 August 2016 at 12:53:26 UTC, Jesper Tholstrup wrote:
On Sunday, 28 August 2016 at 05:21:03 UTC, Tofu Ninja wrote:
Are unicode function names not supported in dmd?
bool ∩(A, B)(A a, B b){
return intersect(a, b);
}
Error: character 0x2229 is not a valid token
Personally, I would prefer 'intersect' as a function name over
'∩' anytime.
Which benifits does the symbols add?
I was just trying it to see if it works. But I think the symbol
is nice for readability, typing it is another matter.
dub generate visuald
I am not sure what changed but I can no longer build using visuald after generating from dub. When I try to build from visual studio I get the following error LINK : warning LNK4001: no object files specified; libraries used LINK : warning LNK4068: /MACHINE not specified; defaulting to X86 LINK : fatal error LNK1561: entry point must be defined I did update visuald recently so I suppose that's what caused it. Updated dub to 1.0 trying to fix this. Anyone else get this, any solution. I can build directly from dub with no problem, but building from VS gives that error.
Inexplicable invalid memory operation when program terminates
I have a program which I have stripped down to a single offending
line which, when present in my program, causes an invalid memory
operation to occur after main has evaluated:
import mach.sdl.window;
void main(){
auto win = new Window(300, 300);
}
The program is a bit larger than that, but I do not get the error
when I comment out that instantiation and the things dependent on
it.
I commented out the body of the constructor that is being called,
and I still get the error.
Am I missing something or is this an obnoxious bug with the GC?
Re: Removing array element in foreach, safe?
On Monday, 5 September 2016 at 15:53:39 UTC, dom wrote:
is this code safe? if not how do i do it correctly?
static AsyncHttpGet[] openRequests;
static void updateRequests()
{
foreach(idx, req; openRequests)
{
if(req.state != Fiber.State.TERM)
req.call();
else
openRequests.remove(idx);
}
}
thx :)
openRequests = openRequests.filter!(a=>a.state !=
Fiber.State.TERM).array;
openRequests.each!((a){ a.call(); });
Re: Removing array element in foreach, safe?
On Monday, 5 September 2016 at 17:38:10 UTC, Daniel Kozak wrote:
On Monday, 5 September 2016 at 15:53:39 UTC, dom wrote:
is this code safe? if not how do i do it correctly?
static AsyncHttpGet[] openRequests;
static void updateRequests()
{
foreach(idx, req; openRequests)
{
if(req.state != Fiber.State.TERM)
req.call();
else
openRequests.remove(idx);
}
}
thx :)
openRequests = openRequests.filter!(a=>a.state !=
Fiber.State.TERM).array;
openRequests.each!((a){ a.call(); });
or
openRequests = openRequests.filter!(a=>a.state != 0).map!((a)
{a.call(); return a;}).array;
Re: Inexplicable invalid memory operation when program terminates
On Monday, 5 September 2016 at 17:33:17 UTC, pineapple wrote:
I have a program which I have stripped down to a single
offending line which, when present in my program, causes an
invalid memory operation to occur after main has evaluated:
import mach.sdl.window;
void main(){
auto win = new Window(300, 300);
}
The program is a bit larger than that, but I do not get the
error when I comment out that instantiation and the things
dependent on it.
I commented out the body of the constructor that is being
called, and I still get the error.
Am I missing something or is this an obnoxious bug with the GC?
InvalidMemoryOperationError is raised when you try to allocate
memory inside a destructor called by the GC. I see from your
repository that the destructor of Window uses a function called
log defined by yourself. That function uses writeln internally.
writeln is not @nogc, so it may be that that call to log in the
destructor is actually allocating memory.
Re: Inexplicable invalid memory operation when program terminates
On Mon, Sep 05, 2016 at 05:33:17PM +, pineapple via Digitalmars-d-learn
wrote:
> I have a program which I have stripped down to a single offending line
> which, when present in my program, causes an invalid memory operation
> to occur after main has evaluated:
>
> import mach.sdl.window;
> void main(){
> auto win = new Window(300, 300);
> }
>
> The program is a bit larger than that, but I do not get the error when
> I comment out that instantiation and the things dependent on it.
>
> I commented out the body of the constructor that is being called, and
> I still get the error.
>
> Am I missing something or is this an obnoxious bug with the GC?
[...]
What does the destructor do?
T
--
"The whole problem with the world is that fools and fanatics are always so
certain of themselves, but wiser people so full of doubts." -- Bertrand
Russell. "How come he didn't put 'I think' at the end of it?" -- Anonymous
Re: Inexplicable invalid memory operation when program terminates
On Monday, 5 September 2016 at 17:33:17 UTC, pineapple wrote: Am I missing something or is this an obnoxious bug with the GC? Oh, I've been trying to figure this out on and off for days and of course five minutes after I post I fix the problem. I'm not really sure why, but it did fix it. In the example the window class destructor was being called. I found that if I did `delete win;` at the end there it worked fine, but otherwise the GC was tripping up? I removed a console output statement and rewrote a thing using a foreach loop instead of a filter range and it stopped complaining. I'm realizing now, too, that the reason I was getting the same error in commits long before I added that particular thing the GC disliked was an entirely different one. That was not fun to debug. On Monday, 5 September 2016 at 17:42:18 UTC, Lodovico Giaretta wrote: InvalidMemoryOperationError is raised when you try to allocate memory inside a destructor called by the GC. I see from your repository that the destructor of Window uses a function called log defined by yourself. That function uses writeln internally. writeln is not @nogc, so it may be that that call to log in the destructor is actually allocating memory. That was in fact part of the problem
Re: Inexplicable invalid memory operation when program terminates
On Mon, Sep 05, 2016 at 05:48:11PM +, pineapple via Digitalmars-d-learn wrote: [...] > In the example the window class destructor was being called. I found > that if I did `delete win;` at the end there it worked fine, but > otherwise the GC was tripping up? I removed a console output statement > and rewrote a thing using a foreach loop instead of a filter range and > it stopped complaining. [...] The problem is caused by trying to allocate memory inside the dtor when the dtor is invoked by the GC. The delete operator is being deprecated, but IIRC it doesn't involve a GC collection run, so the problem is hidden. Basically, class dtors should never do anything involving the GC, and should not depend on any reference member variables still being valid. T -- Never wrestle a pig. You both get covered in mud, and the pig likes it.
Re: dub generate visuald
On Monday, 5 September 2016 at 17:25:45 UTC, Tofu Ninja wrote: I can build directly from dub with no problem, but building from VS gives that error. Building with dub uses the dmd settings in sc.ini Building with VisualD can override those settings.
Re: dependency analysis for makefile construction
On 09/04/2016 12:07 AM, dan wrote:
Are there any FOSS tools for doing dependency analysis of (e.g.) all the
d files in a directory, to let you know when a .o file needs to be
regenerated?
This presumably would depend mostly on the import statements (including
import of any file to be used in string construction, as in 'auto
my_string = import("my_file");').
dmd itself has two related switches:
* -deps prints out imports and such.
* -v prints out the same information in different format, and also a lot
more other stuff, including which dmd binary is being used and the
config file.
rdmd uses -v to figure out the dependencies of the root module. Here's
how it parses the output:
https://github.com/dlang/tools/blob/master/rdmd.d#L643-L691
I'm not aware of a standalone tool that does something like this. If you
want to write one, you could do like rdmd and use `dmd -deps`/`dmd -v`,
or you could use a standalone D parser like libdparse.
http://code.dlang.org/packages/libdparse
[...]
(I'm using gdc, and building with gnumake.)
I'm not sure how similar or different gdc is to dmd with regards to the
-deps/-v switches. A quick test suggests that gdc has a --deps switch
that behaves like dmd's -deps. It seems to be undocumented. The output
of gdc's -v does apparently not include the imports, though.
Re: dub generate visuald
On Monday, 5 September 2016 at 18:22:02 UTC, Guillaume Piolat wrote: On Monday, 5 September 2016 at 17:25:45 UTC, Tofu Ninja wrote: I can build directly from dub with no problem, but building from VS gives that error. Building with dub uses the dmd settings in sc.ini Building with VisualD can override those settings. There is an option to disable that in the visuald settings, but that does not seem to change anything.
Re: dependency analysis for makefile construction
On Monday, 5 September 2016 at 18:22:08 UTC, ag0aep6g wrote: On 09/04/2016 12:07 AM, dan wrote: Are there any FOSS tools for doing dependency analysis of [...] [...] I'm not aware of a standalone tool that does something like this. If you want to write one, you could do like rdmd and use `dmd -deps`/`dmd -v`, or you could use a standalone D parser like libdparse. http://code.dlang.org/packages/libdparse I have one in dastworx, based on dparse: https://github.com/BBasile/Coedit/blob/master/dastworx/src/imports.d#L64 It would be very easy to make it a standalone tool (dastworx is a standalone tool but its main() is specific to Coedit) or to add such an anlayzer to Dscanner. about 200 SLOCs not more.
Re: dub generate visuald
On Monday, 5 September 2016 at 17:25:45 UTC, Tofu Ninja wrote: I am not sure what changed but I can no longer build using visuald after generating from dub. When I try to build from visual studio I get the following error LINK : warning LNK4001: no object files specified; libraries used LINK : warning LNK4068: /MACHINE not specified; defaulting to X86 LINK : fatal error LNK1561: entry point must be defined I did update visuald recently so I suppose that's what caused it. Updated dub to 1.0 trying to fix this. Anyone else get this, any solution. I can build directly from dub with no problem, but building from VS gives that error. I moved my project to a folder that has no spaces in the path, which has changed the error. Now I get: core.exception.RangeError@pipedmd(286): Range violation
Re: dub generate visuald
On Monday, 5 September 2016 at 19:03:00 UTC, Tofu Ninja wrote: On Monday, 5 September 2016 at 17:25:45 UTC, Tofu Ninja wrote: I am not sure what changed but I can no longer build using visuald after generating from dub. When I try to build from visual studio I get the following error LINK : warning LNK4001: no object files specified; libraries used LINK : warning LNK4068: /MACHINE not specified; defaulting to X86 LINK : fatal error LNK1561: entry point must be defined I did update visuald recently so I suppose that's what caused it. Updated dub to 1.0 trying to fix this. Anyone else get this, any solution. I can build directly from dub with no problem, but building from VS gives that error. I moved my project to a folder that has no spaces in the path, which has changed the error. Now I get: core.exception.RangeError@pipedmd(286): Range violation https://issues.dlang.org/show_bug.cgi?id=15606 U it seems that bug has been in visuald for months now... and people wonder why D isn't popular... shit ain't useable.
Re: Removing array element in foreach, safe?
On Monday, 5 September 2016 at 17:38:10 UTC, Daniel Kozak wrote:
On Monday, 5 September 2016 at 15:53:39 UTC, dom wrote:
is this code safe? if not how do i do it correctly?
static AsyncHttpGet[] openRequests;
static void updateRequests()
{
foreach(idx, req; openRequests)
{
if(req.state != Fiber.State.TERM)
req.call();
else
openRequests.remove(idx);
}
}
thx :)
openRequests = openRequests.filter!(a=>a.state !=
Fiber.State.TERM).array;
openRequests.each!((a){ a.call(); });
thx mate!
Re: dependency analysis for makefile construction
On Monday, 5 September 2016 at 18:49:25 UTC, Basile B. wrote: On Monday, 5 September 2016 at 18:22:08 UTC, ag0aep6g wrote: On 09/04/2016 12:07 AM, dan wrote: Are there any FOSS tools for doing dependency analysis of [...] [...] I'm not aware of a standalone tool that does something like this. If you want to write one, you could do like rdmd and use `dmd -deps`/`dmd -v`, or you could use a standalone D parser like libdparse. http://code.dlang.org/packages/libdparse I have one in dastworx, based on dparse: https://github.com/BBasile/Coedit/blob/master/dastworx/src/imports.d#L64 Thanks Basile and also ag0aep6g for your replies, which give me several things to try. dan
Re: Unicode function name? ∩
On Monday, 29 August 2016 at 12:53:26 UTC, Jesper Tholstrup wrote:
On Sunday, 28 August 2016 at 05:21:03 UTC, Tofu Ninja wrote:
Are unicode function names not supported in dmd?
bool ∩(A, B)(A a, B b){
return intersect(a, b);
}
Error: character 0x2229 is not a valid token
Personally, I would prefer 'intersect' as a function name over
'∩' anytime.
Which benifits does the symbols add?
It's concise and has a very specific meaning. If one is working
with mathematical objects and set up correctly then it can be
more easily interpreted because it is `inline` with standard
mathematical syntax.
It's the same reason mathematicians prefer ∩ over intersect. You
would prefer it too if you got used to it. The whole point of
symbols is to simplify, ∩ is more simple than intersect as the
first requires 1 symbol and the second requires 8 symbols.
VisualD core.exception.RangeError@pipedmd(286): Range violation
I get "core.exception.RangeError@pipedmd(286): Range violation" whenever I try to build from visual D. Is there any workaround for this? It was reported[1] almost 9 months ago, does not seem like it's going to be fixed anytime soon. Visual D is completely broken for me right now because of it. Only reason I use Visual D is because it's the only useable debugger on windows, now I can't even do that... Lost a day of work trying to fix this, starting to get really annoyed... [1] https://issues.dlang.org/show_bug.cgi?id=15606
