Re: Abstractioning away main/winMain
On Saturday 05 September 2015 07:52, anonymous wrote:
> This doesn't work because delegates and static initialization don't go
> together. You can use a static constructor:
>
>
> const Application MyApp;
> static this()
> {
> Application.New({import std.stdio; std.stdio.writeln("MY APP IS
> COOL");
Should be: MyApp = Application.New({...});
> });
> }
>
Re: spawn X different workers & wait for results from all of them
On 2015-09-04 17:32:48 +, Justin Whear said: How would receive know? Well, it could be pretty simple. At the moment: receive( int ..., long ..., myStruct ... ) Will wait for one out of the three. So it's an OR. reveive_all( int ..., long ..., myStruct ... ) would finish if every type was returned once (maybe at least once). With this I would have an AND combination. If you're using std.concurrency, the receiving function needs to encode doneness, e.g. const numJobs = 4; foreach (_; 0 .. numJobs) receive(...); That's what you can do if the type is the same. Or just put four receives sequentially in the code. The not so nice side effect is, that you define an order for processing but the tasks might finish in an other order. So, possible work is blocked. Or you could use std.parallelism: foreach (pieceOfWork; parallel(listOfWork)) doIt(pieceOfWork); My "pieceOfWork" is not the same. So I don't have the case: Do 4 time this 1thing. Instead, do 1 time these 4 things. -- Robert M. Münch http://www.saphirion.com smarter | better | faster
Interfacing Chromium & SQLite
On a Mac (Yosemite version), how would I create a window in D, embed Chromium, use D to show a local SQLite test database (id, firstname, lastname) inside Chromium, and let someone have a small search form to do like a "full name" search that goes back to D to query the database again?
Re: Superfluous code in switch statement
On Friday, 4 September 2015 at 21:20:11 UTC, Timon Gehr wrote:
On 09/04/2015 11:12 PM, anonymous wrote:
On Friday 04 September 2015 23:04, Timon Gehr wrote:
DMD never warns about dead code.
It warns here:
import std.stdio;
void main()
{
return;
writeln("hi"); /* Warning: statement is not reachable */
}
You are right, it does. Then I suppose there is no reason why
it shouldn't warn in the switch case.
I see, thanks.
static array is no range?
```
import std.algorithm;
char[1024] buffer;
buffer.find("LOCATION: "); // get error about how all the
different versions of find don't match
```
```
import std.algorithm;
char[1024] buffer;
buffer[0..$].find("LOCATION: "); // works as expected
```
Before trying the slice I manually pragma(msg) all the template
constraints to see why it was failing. Apparently a static array
is not a ForwardRange. Now, there is probably a good reason for
that, that is not what I want to discuss.
The point is that it is rather hard to find out what went wrong.
What I would like the compiler to emit is this: `Error: buffer is
not a ForwardRange`. But I know that wouldn't be so easy.
At least the compiler shouldn't show me candidates with
non-matching arguments length (e.g.
`std.algorithm.searching.find(alias pred, InputRange)(InputRange
haystack) if (isInputRange!InputRange)`)
Re: reading file byLine
On Saturday, 5 September 2015 at 18:57:52 UTC, deed wrote:
On Saturday, 5 September 2015 at 17:31:39 UTC, Namal wrote:
Yeah, I have have been trying this example from wiki books
https://en.wikibooks.org/wiki/Learning_D_With_Project_Euler
It is not even compiling.
What exactly is not compiling?
the last codesample on the bottom. I think because of the old D?
Index for the last array.length-1 is now $-1. But also I get
Error: undefined identifier 'file'
for the read line. But even when I fixed those errors the strings
I got were with those quotation marks and backslashes. However,
with your help I could solve it now.
I moved to the next problem and wrote the program for it
import std.stdio, std.algorithm, std.array;
bool abundant(int n){
int[] a;
foreach(i;1..n)
if(!(n%i))
a~=i;
auto sum = reduce!((a,b)=>a+b)(0,a);
return sum>n;
}
void main(){
long sum;
int[] arr;
int[28123] mark;
foreach(i;1..28124)
if(abundant(i))
arr~=i;
foreach(i;arr)
foreach(j;arr){
if(i+j>28123)
break;
mark[i+j-1] = 1;
}
for(auto i = 0;i
Re: reading file byLine
On Saturday, 5 September 2015 at 17:31:39 UTC, Namal wrote: Yeah, I have have been trying this example from wiki books https://en.wikibooks.org/wiki/Learning_D_With_Project_Euler It is not even compiling. What exactly is not compiling?
Re: Windows Resources
On Saturday, 5 September 2015 at 19:06:15 UTC, Prudence wrote: [...] Check this file https://github.com/D-Programming-Language/dmd/blob/master/samples/winsamp.d ,it's distributed with your D setup.
Create a delegate function
I have code setup in such a way that I call a user defined
function, e.g.,
void myFunc(Data d)
{
}
myFunc has to be passed to the main code using something like
void SetFunc(void function(Data) func) { ... func(myData); }
What I would like to do is, instead of having to pass data to
myFunc(and use the type Data in all the function types), is to
sort of create a delegate:
what I want to do:
void myFunc()
{
this.d; // Ok, because somehow this = Data;
}
then, of course,
void SetFunc(void delegate() func) { func.context = myData;
func(); }
void delegate() dg =
{
auto t = this;
return;
};
doesn't even work because this is not defined.
My guess this is impossible without compiler support.
effectively though, I don't see why we can't use this(because
myFunc is being executed in a context, I simply want to set it to
the right one so that the user can take advantage of it...
instead of having to pass an argument instead.
Any ideas how to do this? It seems we can't actually create
"delegate objects" but only delegate pointers? (simply because of
the restrictions the compiler places on *this*. (can't be used
outside of a context, even though we can always guarantee it is
in a context)
How bout a new syntax for such concepts?
void delegate!T(...) dg
{
}
// identical to
void dg(T this, ...)
{
}
Hence, to call dg, we have to pass it a "this" object... hence it
has a context. They can be called just like functions. dg(myData,
...);
Windows Resources
I'm trying to create a win32 window. I coped the code pretty much
directly from msdn:
MSG msg;
BOOL bRet;
WNDCLASS wc;
// Register the window class for the main window.
if (!hPrevInstance)
{
wc.style = 0;
wc.lpfnWndProc = cast(WNDPROC)
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
//wc.hIcon = LoadIcon(cast(HINSTANCE) NULL,
IDI_APPLICATION);
//wc.hCursor = LoadCursor(cast(HINSTANCE) NULL,
IDC_ARROW);
wc.hIcon = NULL;
wc.hCursor = NULL;
wc.hbrBackground = GetStockObject(WHITE_BRUSH);
wc.lpszMenuName = "MainMenu";
wc.lpszClassName = "MainWndClass";
if (!RegisterClass())
return FALSE;
}
// Create the main window.
hwndMain = CreateWindow("MainWndClass", "Sample",
WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT, cast(HWND) NULL,
cast(HMENU)
NULL, hInstance, cast(LPVOID) NULL);
if (!hwndMain)
{
auto x = GetLastError();
return FALSE;
}
x is 1812 = ERROR_RESOURCE_DATA_NOT_FOUND
That's about as far as I can get. (what resource data? Where I do
put it? How, who, when?)
Re: reading file byLine
On Saturday, 5 September 2015 at 14:49:13 UTC, deed wrote: On Saturday, 5 September 2015 at 14:44:19 UTC, deed wrote: .map!(s => chomp(s, "\"") .map!(s => chompPrefix(s, "\"") should be .map!(s => chomp(s, "\"")) .map!(s => chompPrefix(s, "\"")) Yeah, I have have been trying this example from wiki books https://en.wikibooks.org/wiki/Learning_D_With_Project_Euler It is not even compiling.
Re: Interfacing Chromium & SQLite
On Saturday, 5 September 2015 at 13:32:04 UTC, Mike McKee wrote: Note: I'm not asking for source code examples, just wondering what technologies I would have to use to connect these pieces together? I would basically look up how you'd do it in C and follow the same steps in D. I haven't used Chrominum though so I don't know more than that...
Re: reading file byLine
On Saturday, 5 September 2015 at 12:41:37 UTC, Namal wrote:
Thx guys. Now I try out the split function. I read the file as
a single string?
auto arr = split(cast(string)read(filename),",");
where the file has "A", "B", "C"
and I get the output ["\"A\"", " \"B\"", " \"C\"\n"]
I can understand that read functions reads the endl but what
does it with the quotation marks? how can I modify read so I
get just ["A", "B", "C"]
'\' is the escape character and is used to disambiguate start or
end of string (") and a quotation mark within the string (\"),
the same way as "\n" means newline and not '\' 'n', which would
have been "\\n".
So what you have is [`"A"`, ` "B"`, ` "C"\n`], if you use ` for
start\stop of string. You say you want ["A", "B", "C"], so you
need to remove whitespace. You can do that with std.string.strip.
Assuming you also want to remove the quotation marks present in
the file, one solution is to use std.string.chomp and
std.string.chompPrefix, for example:
string s = cast(string) read(filename);
s.split(",")
.map!strip
.map!(s => chomp(s, "\"")
.map!(s => chompPrefix(s, "\"")
.writeln
;
Re: spawn X different workers & wait for results from all of them
On Thursday, 3 September 2015 at 16:50:21 UTC, Robert M. Münch wrote: Hi, I'm not sure how to best implement the following: 1. I have 4 different tasks to do. 2. All can run in parallel 3. Every task will return some result that I need Now how to best do it? I think the Task and taskPool from std.parallelism are a good fit. Something like: auto task1 = task!fun1(params1); auto task2 = task!fun2(params2); auto task3 = task!fun3(params3); auto task4 = task!fun4(params4); taskPool.put(task1); taskPool.put(task2); taskPool.put(task3); taskPool.put(task4); auto res1 = task1.workForce(); auto res2 = task2.workForce(); auto res3 = task3.workForce(); auto res4 = task4.workForce(); //here we have all the results, they were calculated in parallel
Re: spawn X different workers & wait for results from all of them
On 2015-09-05 15:44:02 +, thedeemon said: I think the Task and taskPool from std.parallelism are a good fit. Something like: auto task1 = task!fun1(params1); auto task2 = task!fun2(params2); auto task3 = task!fun3(params3); auto task4 = task!fun4(params4); taskPool.put(task1); taskPool.put(task2); taskPool.put(task3); taskPool.put(task4); auto res1 = task1.workForce(); auto res2 = task2.workForce(); auto res3 = task3.workForce(); auto res4 = task4.workForce(); //here we have all the results, they were calculated in parallel Thanks, that looks pretty good. Going to x-check how this could be used. -- Robert M. Münch http://www.saphirion.com smarter | better | faster
Re: reading file byLine
On Friday, 4 September 2015 at 12:09:19 UTC, Edwin van Leeuwen
wrote:
On Friday, 4 September 2015 at 12:06:08 UTC, Edwin van Leeuwen
wrote:
On Friday, 4 September 2015 at 11:50:23 UTC, deed wrote:
import std.algorithm, std.range, std.array, std.string,
std.stdio,
std.conv;
int[] arr1 = [1, 2, 30];
//arr1.max.writeln; // Doesn't work, as you say
arr1.reduce!max.writeln;// This does. Prints 30.
Again using reduce is the functional way to do it. The above
basically boils down to:
int[] arr1 = [1, 2, 30];
int maxElement = arr1[1];
foreach( element; arr1[2..$] ) //2..$ is short hand for second
till last ($) element
{
maxElement = max( maxElement, element );
}
writeln( maxElement );
Sorry been using too much R, so my indexes are off by 1:
int[] arr1 = [1, 2, 30];
int maxElement = arr1[0];
foreach( element; arr1[1..$] ) //1..$ is short hand for second
till last ($) element
{
maxElement = max( maxElement, element );
}
writeln( maxElement );
Thx guys. Now I try out the split function. I read the file as a
single string?
auto arr = split(cast(string)read(filename),",");
where the file has "A", "B", "C"
and I get the output ["\"A\"", " \"B\"", " \"C\"\n"]
I can understand that read functions reads the endl but what does
it with the quotation marks? how can I modify read so I get just
["A", "B", "C"]
Re: reading file byLine
On Saturday, 5 September 2015 at 14:44:19 UTC, deed wrote: .map!(s => chomp(s, "\"") .map!(s => chompPrefix(s, "\"") should be .map!(s => chomp(s, "\"")) .map!(s => chompPrefix(s, "\""))
Re: Windows Resources
On Saturday, 5 September 2015 at 19:06:15 UTC, Prudence wrote: That's about as far as I can get. (what resource data? Where I do put it? How, who, when?) Resource data in Windows is data compiled into your exe. It is stuff like icons, menus, or other arbitrary stuff you attach. However, the code you posted doesn't access any of that so it shouldn't be an issue here... what import did you use to access the windows api? `import core.sys.windows.windows;` or something else? Also, are you building 32 bit (the default) or 64 bit?
Re: static array is no range?
On Saturday, 5 September 2015 at 11:12:17 UTC, Sebastiaan Koppe
wrote:
```
import std.algorithm;
char[1024] buffer;
buffer.find("LOCATION: "); // get error about how all the
different versions of find don't match
```
```
import std.algorithm;
char[1024] buffer;
buffer[0..$].find("LOCATION: "); // works as expected
```
You can do instead:
buffer[].find("LOCATION: ");
Before trying the slice I manually pragma(msg) all the template
constraints to see why it was failing. Apparently a static
array is not a ForwardRange. Now, there is probably a good
reason for that, that is not what I want to discuss.
The point is that it is rather hard to find out what went wrong.
What I would like the compiler to emit is this: `Error: buffer
is not a ForwardRange`. But I know that wouldn't be so easy.
At least the compiler shouldn't show me candidates with
non-matching arguments length (e.g.
`std.algorithm.searching.find(alias pred,
InputRange)(InputRange haystack) if (isInputRange!InputRange)`)
Yes, static arrays aren't ranges. The main reason is that static
arrays are value type (ie: you copy them arround when passing
them to functions which usually has a huge cost) where ranges are
reference type (no copy, lighter, not always better as it makes
optimisation more complicated).
The standard library is designed arround ranges to make sure that
you are not copying 1024-bytes long structures arround by
accident: you'd have to do that explicitely. As a consequence,
you must generally slice arrays when passing them to phobos
functions (not always true but a good rule of thumb).
That said, if you want to benefit from array-specific
optimisations such as loop-unrolling you are generally better of
using a good old foreach and implementing the logic yourself.
Yes, it is sad, I agree.
Re: Windows Resources
This may interest you: https://github.com/Devisualization/window/blob/master/platforms/win32/devisualization/window/window.d
Re: Windows Resources
On Sunday, 6 September 2015 at 00:29:13 UTC, Adam D. Ruppe wrote: On Saturday, 5 September 2015 at 19:06:15 UTC, Prudence wrote: That's about as far as I can get. (what resource data? Where I do put it? How, who, when?) Resource data in Windows is data compiled into your exe. It is stuff like icons, menus, or other arbitrary stuff you attach. However, the code you posted doesn't access any of that so it shouldn't be an issue here... what import did you use to access the windows api? `import core.sys.windows.windows;` or something else? Also, are you building 32 bit (the default) or 64 bit? 32-bit and I'm using the latest win32 wrappers distributed on github from someone. (suppose to be more complete than core.sys.windows) Obviously the issue is that I'm not using any resources yet it is giving me such an error. (again, I pretty much copied the code directly from MSDN)
Re: static array is no range?
On Sunday, 6 September 2015 at 00:25:10 UTC, cym13 wrote:
Yes, static arrays aren't ranges. The main reason is that
static arrays are value type (ie: you copy them arround when
passing them to functions which usually has a huge cost) where
ranges are reference type (no copy, lighter, not always better
as it makes optimisation more complicated).
The standard library is designed arround ranges to make sure
that you are not copying 1024-bytes long structures arround by
accident: you'd have to do that explicitely. As a consequence,
you must generally slice arrays when passing them to phobos
functions (not always true but a good rule of thumb).
That actually makes a lot of sense.
That said, if you want to benefit from array-specific
optimisations such as loop-unrolling you are generally better
of using a good old foreach and implementing the logic
yourself. Yes, it is sad, I agree.
While I like speed, 95% of my applications can be 4x as slow, and
no-one would give a damn. Plus, I have only limited time so I try
to be efficient by writing as little code as possible (while
still getting work done.)
What I was trying to say is that endorsed idiomatic D code (UFCS
combined with function overloading+constraints), produces
terrible error messages. Which means every newcomer sees that
awful stuff and decides to implement said algorithm himself. That
is not productivity.
This is arguably the poorest and most neglected aspect of D.
Without messing up internals the best I can think of is this:
```
auto forwardRange(alias R)()
{
import std.traits;
import std.range;
static if(!isForwardRange!(typeof(R))) static
assert(0,"Nonono... "~__traits(identifier,R)~" not a
ForwardRange");
return R;
}
unittest
{
char[1024] buffer;
import std.algorithm;
forwardRange!buffer.find("LOCATION: ");
}
```
Which is ugly as hell, and probably even worse than the current
state.
Re: Create a delegate function
On Saturday, 5 September 2015 at 18:00:53 UTC, Prudence wrote:
I have code setup in such a way that I call a user defined
function, e.g.,
void myFunc(Data d)
{
}
myFunc has to be passed to the main code using something like
You can do that if and only if the this is the last argument to
the function and is a pointer.
Even then, you're kinda hacking it, but with casts you can make
it work:
struct Test {
int a;
}
void foo(Test* _this) {
_this.a = 10;
}
void main() {
auto _this = new Test();
void delegate() dg;
dg.funcptr = cast(typeof(dg.funcptr))
dg.ptr = _this;
dg();
import std.stdio;
writeln(_this.a);
}
You could probably put that in a template that does better type
checking.
But the idea is that a delegate is simply a pair of function
pointer and context pointer. When you call it, it automatically
adds the context pointer as the last hidden argument to the
function.
Knowing how it works at the low level, we can use some casts to
get the compiler to trust us and make it work.
Similarly with arguments:
struct Test {
int a;
}
void foo(int a, Test* _this) {
_this.a = 10 + a;
}
void main() {
auto _this = new Test();
void delegate(int) dg;
dg.funcptr = cast(typeof(dg.funcptr))
dg.ptr = _this;
dg(10);
import std.stdio;
writeln(_this.a);
}
To type check this, you could probably use
ParameterTypeTuple!foo[0 .. $-1] and check for match there on the
typeof(dg.funcptr). And check return value and that the last
argument is indeed a pointer of the type you are giving.
Re: Create a delegate function
On Saturday, 5 September 2015 at 18:00:53 UTC, Prudence wrote:
I have code setup in such a way that I call a user defined
function, e.g.,
void myFunc(Data d)
{
}
myFunc has to be passed to the main code using something like
void SetFunc(void function(Data) func) { ... func(myData); }
What I would like to do is, instead of having to pass data to
myFunc(and use the type Data in all the function types), is to
sort of create a delegate:
what I want to do:
void myFunc()
{
this.d; // Ok, because somehow this = Data;
}
then, of course,
void SetFunc(void delegate() func) { func.context = myData;
func(); }
void delegate() dg =
{
auto t = this;
return;
};
doesn't even work because this is not defined.
My guess this is impossible without compiler support.
effectively though, I don't see why we can't use this(because
myFunc is being executed in a context, I simply want to set it
to the right one so that the user can take advantage of it...
instead of having to pass an argument instead.
Any ideas how to do this? It seems we can't actually create
"delegate objects" but only delegate pointers? (simply because
of the restrictions the compiler places on *this*. (can't be
used outside of a context, even though we can always guarantee
it is in a context)
How bout a new syntax for such concepts?
void delegate!T(...) dg
{
}
// identical to
void dg(T this, ...)
{
}
Hence, to call dg, we have to pass it a "this" object... hence
it has a context. They can be called just like functions.
dg(myData, ...);
Wow, it's hard to get what you mean. It's a bit confuse.
But, IIUC you want to link the parameter value to the delegate
type ?
If so then it's time for you to lean 'std.typecons.Tuple' and
'std.typecons.tuple'.
For example, is this what you meant ?
---
module runnable;
import std.stdio;
import std.typecons;
import std.traits;
alias Fun = void function(int);
alias FunAndData = Tuple!(Fun, ParameterTypeTuple!Fun);
struct MainCode
{
int myData;
void setFunc(FunAndData funAndData)
{
funAndData[0](funAndData[1..$]);
}
}
void test(int param)
{
writeln(param);
}
void main(string[] args)
{
MainCode mainCode;
mainCode.setFunc(tuple(,46));
}
---
