Re: Reading a structured binary file?
On Tue, Aug 06, 2013 at 06:48:12AM +0200, Jesse Phillips wrote: [...] The only way I'm seeing to advance through the file is to keep an index on where you're currently reading from. This actually works perfect for the FileRange I mentioned in the previous post. Though I'm not familiar with how mmfile manages its memory, but hopefully there isn't buffer reuse or storing the slice could be overridden (not an issue for value data, but string data). I don't know about D's Mmfile, but AFAIK, it maps directly to the OS mmap(), which basically maps a portion of your program's address space to the data on the disk. Meaning that the memory is managed by the OS, and addresses will not change from under you. In the underlying physical memory, pages may get swapped out and reused, but this is invisible to your program, since referencing them will cause the OS to swap the pages back in, so you'll never end up with invalid pointers. The worst that could happen is the I/O performance hit associated with swapping. Such is the utility of virtual memory. T -- Error: Keyboard not attached. Press F1 to continue. -- Yoon Ha Lee, CONLANG
Re: Getting number of messages in MessageBox
Ali Çehreli wrote: On 08/05/2013 04:18 PM, Marek Janukowicz wrote: I'm using std.concurrency message passing and I'd like to check which thread might be a bottleneck. The easiest would be check number of messages piled up for each of them, but I could not find a way to do that. Is it possible? Every detail about MessageBox seems to be hidden... Would setMaxMailboxSize() be helpful? void setMaxMailboxSize(Tid tid, size_t messages, bool function(Tid) onCrowdingDoThis); You can set a limit (perhaps that is lower than normal operation) and report whenever a particular Tid's MessageBox gets full. Well, while this could help a little, it's not really what I'm looking for. I'd like to dump message counts for various threads periodically and see how it fluctuates over time. With the solution you propose I could only check how often a certain limit is hit. -- Marek Janukowicz
Re: Reading a structured binary file?
On Monday, August 05, 2013 23:04:58 H. S. Teoh wrote: On Tue, Aug 06, 2013 at 06:48:12AM +0200, Jesse Phillips wrote: [...] The only way I'm seeing to advance through the file is to keep an index on where you're currently reading from. This actually works perfect for the FileRange I mentioned in the previous post. Though I'm not familiar with how mmfile manages its memory, but hopefully there isn't buffer reuse or storing the slice could be overridden (not an issue for value data, but string data). I don't know about D's Mmfile, but AFAIK, it maps directly to the OS mmap(), which basically maps a portion of your program's address space to the data on the disk. Meaning that the memory is managed by the OS, and addresses will not change from under you. In the underlying physical memory, pages may get swapped out and reused, but this is invisible to your program, since referencing them will cause the OS to swap the pages back in, so you'll never end up with invalid pointers. The worst that could happen is the I/O performance hit associated with swapping. Such is the utility of virtual memory. mmap is awesome. It makes handling large files _way_ easier, especially when you have to worry about performance. It was a huge performance boost for one of our video recorder programs where I work when we switched to using mmap on it (this device is recording multiple video streams from cameras 24/7, and performance is critical). Trying to do what mmap does on your own is incredibly bug-prone and bound to be worse for performance (since you're doing it instead of the kernel). One of our older products tries to do it on its own (probably because the developers didn't know about mmap), and it's a royal mess. - Jonathan M Davis
Re: tuple parameter fwd
On Tuesday, 6 August 2013 at 05:07:51 UTC, Ali Çehreli wrote:
On 08/05/2013 09:51 PM, kdmult wrote:
On Monday, 5 August 2013 at 18:45:49 UTC, kdmult wrote:
class A(P...) {}
class B(R = A!P, P...) {}
P... should be rightmost, so how can I use it in the
preceding parameter?
The default parameter value doesn't make sense as it's shown
above.
Actually I want to port C++ code which looks like below.
template typename P1
class A1 {};
template typename P1, typename R=A1P1
class B1 {}
template typename P1, typename P2
class A2 {};
template typename P1, typename P2, typename R=A2P1,P2
class B2 {}
and so on.
I would use the variadic template parameters. However, I have
no idea
how it can be done. Please advise.
Thanks.
Direct translation seems to work:
class A1(P1) {}
class B1(P1, R = A1!P1) {}
class A2(P1, P2) {}
class B2(P1, P2, R = A2!(P1, P2)) {}
void main()
{
auto a1 = new A1!int;
auto b1d = new B1!int;
auto b1 = new B1!(int, A1!double);
auto a2 = new A2!(int, double);
auto b2d = new B2!(int, double);
auto b2 = new B2!(int, double, A2!(char, short));
}
Ali
Is there a way to use variadic template/class parameter instead
of P1, P2, ..., PN ? If it is I could create 2 templated classes
instead of all that copy/pasted classes with P1, P2, etc
parameters.
Thanks.
Re: Which option is faster...
On Monday, August 05, 2013 15:59:23 jicman wrote:
Greetings!
I have this code,
foreach (...)
{
if (std.string.tolower(fext[0]) == doc ||
std.string.tolower(fext[0]) == docx ||
std.string.tolower(fext[0]) == xls ||
std.string.tolower(fext[0]) == xlsx ||
std.string.tolower(fext[0]) == ppt ||
std.string.tolower(fext[0]) == pptx)
continue;
}
foreach (...)
{
if (std.string.tolower(fext[0]) == doc)
continue;
if (std.string.tolower(fext[0]) == docx)
continue;
if (std.string.tolower(fext[0]) == xls)
continue;
if (std.string.tolower(fext[0]) == xlsx)
continue;
if (std.string.tolower(fext[0]) == ppt)
continue;
if (std.string.tolower(fext[0]) == pptx)
continue;
...
...
}
As others have pointed out, the two code snippets are semantically identical,
and there's a decent chance that the compiler will generate identical code for
both. It wouldn't surprise me if the first snippet resulted in more concise
assembly code, but there shouldn't be any performance difference between the
two. But the first snippet is cleaner, so between those two, you should use
that.
Of course, as others have pointed out, it would be far more efficient to simply
calculate std.string.tolower(fext[0]) once and re-use the result, which should
be a very large performance gain here (assuming that the code around it
doesn't dwarf it in cost). However, another possibility that I don't think
anyone has pointed out is std.string.icmp, which will do case-insensitive
comparison, meaning that you could do
if(fext[0].icmp(doc) == 0 || fext[0].icmp(docx) == 0 || ...)
and that might be more efficient as it avoids having to allocate a new string
when fext[0] isn't all lowercase already. However, you would have to benchmark
the code to be sure, since depending on the typical input, the code around
this code, and how many times this code gets called, calling toLower once
could be more efficient or using icmp could be more efficient, since toLower
allocates whereas icmp doesn't, but icmp does more comparisons that a simple
==. But if you really care about efficiency, you should try both ways and see
which is faster for your use case.
- Jonathan M Davis
Re: Getting number of messages in MessageBox
On Tuesday, 6 August 2013 at 06:15:20 UTC, Marek Janukowicz wrote: Ali Çehreli wrote: On 08/05/2013 04:18 PM, Marek Janukowicz wrote: I'm using std.concurrency message passing and I'd like to check which thread might be a bottleneck. The easiest would be check number of messages piled up for each of them, but I could not find a way to do that. Is it possible? Every detail about MessageBox seems to be hidden... Would setMaxMailboxSize() be helpful? void setMaxMailboxSize(Tid tid, size_t messages, bool function(Tid) onCrowdingDoThis); You can set a limit (perhaps that is lower than normal operation) and report whenever a particular Tid's MessageBox gets full. Well, while this could help a little, it's not really what I'm looking for. I'd like to dump message counts for various threads periodically and see how it fluctuates over time. With the solution you propose I could only check how often a certain limit is hit. Why not go for the trivial solution - just increase/decrease a counter for each push/pop message?
Re: Getting number of messages in MessageBox
Gabi wrote: Why not go for the trivial solution - just increase/decrease a counter for each push/pop message? Yeah, that's most likely what I'll end up with, but it's a pity such information exists and I only can't access it because someone decided to make it private... or should I file a bug (or rather feature request) about it? -- Marek Janukowicz
Re: Getting number of messages in MessageBox
Am 06.08.2013 09:30, schrieb Marek Janukowicz: Gabi wrote: Why not go for the trivial solution - just increase/decrease a counter for each push/pop message? Yeah, that's most likely what I'll end up with, but it's a pity such information exists and I only can't access it because someone decided to make it private... or should I file a bug (or rather feature request) about it? the question is do the published counter then needs locking - and make it slow for all - just for beeing getable?
Re: Getting number of messages in MessageBox
dennis luehring wrote: the question is do the published counter then needs locking - and make it slow for all - just for beeing getable? Good point - but I believe the code operating on the counter is synchronized already, so synchronized getter would not really slow things down. -- Marek Janukowicz
X11 XSynchronize() definition in D
Hi, I'm working with the X11 library available from https://github.com/D-Programming-Deimos/libX11 If I try to call XSynchronize(display, True) the compilation fails with Error: function deimos.X11.Xlib.XSynchronize (_XDisplay*) is not callable using argument types (_XDisplay*, int) I am sure the arguments are correct (see http://goo.gl/8Hzn8s for example) so I think there is a conversion problem between the C and D definition of the function: --- Xlib.h extern int (*XSynchronize( Display*/* display */, Bool/* onoff */ ))( Display*/* display */ ); --- Xlib.d extern int function( Display*/* display */, Bool/* onoff */ )XSynchronize( Display*/* display */ ); Also I can't understand why the C version is not extern int XSynchronize(Display*, Bool); which would be the simplest definition.
Re: Getting number of messages in MessageBox
On Tuesday, 6 August 2013 at 07:47:10 UTC, Marek Janukowicz wrote: dennis luehring wrote: the question is do the published counter then needs locking - and make it slow for all - just for beeing getable? Good point - but I believe the code operating on the counter is synchronized already, so synchronized getter would not really slow things down. I agree that this is much needed feature. In python for example, the threaded Queue class has qsize() method that returns the APPROX size of the queue. Without it my life would be much harder-I use it frequently.
Re: X11 XSynchronize() definition in D
andrea9940: extern int function( Display*/* display */, Bool/* onoff */ )XSynchronize( Display*/* display */ ); Try extern(C)? Bye, bearophile
Re: Getting number of messages in MessageBox
On Aug 5, 2013, at 4:18 PM, Marek Janukowicz ma...@janukowicz.net wrote: I'm using std.concurrency message passing and I'd like to check which thread might be a bottleneck. The easiest would be check number of messages piled up for each of them, but I could not find a way to do that. Is it possible? Every detail about MessageBox seems to be hidden... Not currently. It wouldn't be hard to add a function to get the count used by setMaxMailboxSize though. I'll make a note to add it.
Re: X11 XSynchronize() definition in D
On Tuesday, 6 August 2013 at 08:21:26 UTC, bearophile wrote: Try extern(C)? It's not a linkage error, it's a syntax one
Re: tuple parameter fwd
On 08/05/2013 11:45 AM, kdmult wrote:
Hi,
I would like to use a tuple template parameter in the default value of
another template parameter in the same class declaration as follows.
class A(P...) {}
class B(R = A!P, P...) {}
P... should be rightmost, so how can I use it in the preceding parameter?
Thanks.
Do you mean that when P[0] is already an instance of A, then R should be
P[0]. Otherwise, R should be A!P? If so, the following works:
class A(P...)
{
pragma(msg, \nA: ~ P.stringof);
}
class BImpl(R, P...)
{
pragma(msg, R: ~ R.stringof ~ , P: ~ P.stringof);
}
template B(P...)
{
static if (is (P[0] == A!U, U)) {
/* The first type is already an A instance. Accept the types as
is. */
alias B = BImpl!P;
} else {
/* The first type is not an A instance. Inject one. */
alias B = BImpl!(A!P, P);
}
}
void main()
{
auto b0 = new B!(int, double, char);
auto b1 = new B!(A!long, int, double);
}
Ali
Re: X11 XSynchronize() definition in D
On 08/06/2013 01:01 AM, andrea9940 wrote:
Hi, I'm working with the X11 library available from
https://github.com/D-Programming-Deimos/libX11
If I try to call XSynchronize(display, True) the compilation fails with
Error: function deimos.X11.Xlib.XSynchronize (_XDisplay*) is not
callable using argument types (_XDisplay*, int)
I am sure the arguments are correct (see http://goo.gl/8Hzn8s for
example) so I think there is a conversion problem between the C and D
definition of the function:
--- Xlib.h
extern int (*XSynchronize(
Display*/* display */,
Bool/* onoff */
))(
Display*/* display */
);
I have written the following stubs for C:
typedef void Display;
typedef int Bool;
extern int (*XSynchronize(
Display*/* display */,
Bool/* onoff */
))(
Display*/* display */
);
typedef int(*PreviousAfterFunction)(Display*);
int previous_after_foo(Display* display)
{
return 0;
}
PreviousAfterFunction XSynchronize(Display* display, Bool onoff)
{
return previous_after_foo;
}
int main()
{
int (*paf)(Display*) = XSynchronize(0, 1);
paf(0);
}
And then I have written the direct translation in D, which works as well:
struct Display
{}
alias PreviousAfterFunction = int function(Display*);
int previousAfterFoo(Display *)
{
return 0;
}
PreviousAfterFunction XSynchronize(Display*, bool)
{
return previousAfterFoo;
}
void main()
{
PreviousAfterFunction paf = XSynchronize(null, 1);
paf(null);
}
--- Xlib.d
extern int function(
Display*/* display */,
Bool/* onoff */
)XSynchronize(
Display*/* display */
);
It looks like Xlib.d got it backwards: XSynchronize takes two parameters
and returns a function pointer that takes a single parameter. It should
be the following:
int function(Display*) XSynchronize(Display*, bool);
Also I can't understand why the C version is not extern int
XSynchronize(Display*,
Bool); which would be the simplest definition.
That's different. That would be a function taking two parameters and
returning int. However, XSynchronize takes two parameters and return a
function pointer (that takes one parameter and returns an int).
Ali
Re: X11 XSynchronize() definition in D
struct Display
{}
D supports opaque structs/pointers
struct Display;
Now Display has to be used as pointer only or the compiler complains
e.g. about
Display display;
Re: X11 XSynchronize() definition in D
@Ali Çehreli Thank you for the explanation. I'll send a pull request to fix Xlib.d
Re: Get attributes of type by string name
On 2013-08-02 03:02, JS wrote:
how can I get the UDA's of a type that I only know by name and only in a
CTFE.
I would like to loop over an array of names passed to a me(I don't know
their contents beforehand) and get the attributes.
I've tried to use a mixin but I can't get the mixin to work on the
string name...
e.g., mixin(alias a = __traits(getAttributes, ~type~););
You need to use a typetuple as well:
import std.typetuple;
enum attribute;
@attribute struct Foo {}
void main ()
{
alias a = TypeTuple!(__traits(getAttributes, mixin(Foo)));
pragma(msg, a);
}
--
/Jacob Carlborg
Re: Which option is faster...
On Tuesday, 6 August 2013 at 04:10:57 UTC, Andre Artus wrote:
On Monday, 5 August 2013 at 13:59:24 UTC, jicman wrote:
Greetings!
I have this code,
foreach (...)
{
if (std.string.tolower(fext[0]) == doc ||
std.string.tolower(fext[0]) == docx ||
std.string.tolower(fext[0]) == xls ||
std.string.tolower(fext[0]) == xlsx ||
std.string.tolower(fext[0]) == ppt ||
std.string.tolower(fext[0]) == pptx)
continue;
}
foreach (...)
{
if (std.string.tolower(fext[0]) == doc)
continue;
if (std.string.tolower(fext[0]) == docx)
continue;
if (std.string.tolower(fext[0]) == xls)
continue;
if (std.string.tolower(fext[0]) == xlsx)
continue;
if (std.string.tolower(fext[0]) == ppt)
continue;
if (std.string.tolower(fext[0]) == pptx)
continue;
...
...
}
thanks.
josé
What exactly are you trying to do with this? I get the
impression that there is an attempt at local optimization
when broader approach could lead to better results.
For instance. Using the OS's facilities to filter (six
requests, one each for *.doc, *.docx) could actually end up
being a lot faster.
If you could give more detail about what you are trying to
achieve then it could be possible to get better results.
The files are in a network drive and doing a list foreach *.doc,
*.docx, etc. will be more expensive than getting the list of all
the files at once and then processing them accordingly.
Re: tuple parameter fwd
On Tuesday, 6 August 2013 at 09:53:33 UTC, Ali Çehreli wrote:
Do you mean that when P[0] is already an instance of A, then R
should be P[0]. Otherwise, R should be A!P? If so, the
following works:
class A(P...)
{
pragma(msg, \nA: ~ P.stringof);
}
class BImpl(R, P...)
{
pragma(msg, R: ~ R.stringof ~ , P: ~ P.stringof);
}
template B(P...)
{
static if (is (P[0] == A!U, U)) {
/* The first type is already an A instance. Accept the
types as is. */
alias B = BImpl!P;
} else {
/* The first type is not an A instance. Inject one. */
alias B = BImpl!(A!P, P);
}
}
void main()
{
auto b0 = new B!(int, double, char);
auto b1 = new B!(A!long, int, double);
}
Ali
Great! Thanks Ali.
Re: Which option is faster...
On 8/5/13, H. S. Teoh hst...@quickfur.ath.cx wrote: If you really want optimal performance, use std.regex: Yes and if you also want to bloat your executable to the point that other parts of the system start slowing down.
Re: Which option is faster...
On Tue, Aug 06, 2013 at 02:32:11PM +0200, jicman wrote: On Tuesday, 6 August 2013 at 04:10:57 UTC, Andre Artus wrote: [...] What exactly are you trying to do with this? I get the impression that there is an attempt at local optimization when broader approach could lead to better results. For instance. Using the OS's facilities to filter (six requests, one each for *.doc, *.docx) could actually end up being a lot faster. If you could give more detail about what you are trying to achieve then it could be possible to get better results. The files are in a network drive and doing a list foreach *.doc, *.docx, etc. will be more expensive than getting the list of all the files at once and then processing them accordingly. In this case, the bottleneck most likely is in the network latency, so optimizing string comparisons won't get you very far. You should instead be focusing on how to improve the performance of network accesses. What kind of processing are you doing with the filtered list of files? If it's a complicated operation, you might want to consider having a separate thread for fetching the list of files while work is being done on them in the main thread. T -- Computers shouldn't beep through the keyhole.
apply function to parameters
In C++11 we can write:
templateclass... Args
void somefunc(Args... args {
...
}
templateclass T
T process(T p) {
...
}
template class... Args
void foo(Args... args) {
somefunc(process(args)...);
}
Is there a simple way to do this in D?
Re: apply function to parameters
In other words, I need something like this: foo(magicTemplate!(f, a1, a2, a3...)) === foo(f(a1), f(a2), f(a3)...)
Re: apply function to parameters
Jack Applegame: Is there a simple way to do this in D? somefunc(process(args)); Bye, bearophile
Re: apply function to parameters
Jack Applegame: In other words, I need something like this: foo(magicTemplate!(f, a1, a2, a3...)) === foo(f(a1), f(a2), f(a3)...) Sorry, your second post was not yet present and I misunderstood your question. Take a look at std.typetuple.staticMap Bye, bearophile
Re: Which option is faster...
On Tuesday, 6 August 2013 at 12:32:13 UTC, jicman wrote:
On Tuesday, 6 August 2013 at 04:10:57 UTC, Andre Artus wrote:
On Monday, 5 August 2013 at 13:59:24 UTC, jicman wrote:
Greetings!
I have this code,
foreach (...)
{
if (std.string.tolower(fext[0]) == doc ||
std.string.tolower(fext[0]) == docx ||
std.string.tolower(fext[0]) == xls ||
std.string.tolower(fext[0]) == xlsx ||
std.string.tolower(fext[0]) == ppt ||
std.string.tolower(fext[0]) == pptx)
continue;
}
foreach (...)
{
if (std.string.tolower(fext[0]) == doc)
continue;
if (std.string.tolower(fext[0]) == docx)
continue;
if (std.string.tolower(fext[0]) == xls)
continue;
if (std.string.tolower(fext[0]) == xlsx)
continue;
if (std.string.tolower(fext[0]) == ppt)
continue;
if (std.string.tolower(fext[0]) == pptx)
continue;
...
...
}
thanks.
josé
What exactly are you trying to do with this? I get the
impression that there is an attempt at local optimization
when broader approach could lead to better results.
For instance. Using the OS's facilities to filter (six
requests, one each for *.doc, *.docx) could actually end
up being a lot faster.
If you could give more detail about what you are trying to
achieve then it could be possible to get better results.
The files are in a network drive and doing a list foreach
*.doc, *.docx, etc. will be more expensive than getting the
list of all the files at once and then processing them
accordingly.
Again, what are you trying to achieve?
Your statement is not necessarily true, for a myriad of reasons,
but it entirely depends on what you want to do.
I would reiterate Dennis Luehring's reply, why are you not
benching? It seems like you are guessing at what the problems
are, that's hardly ever useful.
One of the first rules of network optimization is to reduce the
amount od data, that normally means filtering.at the server, the
next thing is coarse grained is better than fine (BOCTAOE/L).
Re: X11 XSynchronize() definition in D
On 08/06/2013 03:22 AM, David wrote: struct Display
{}
D supports opaque structs/pointers
struct Display;
Now Display has to be used as pointer only or the compiler complains
e.g. about
Display display;
Yes and I am sure that is how Xlib.d has it.
However, remembering a limitation that we have discovered a couple of
weeks ago, I intentionally did not make it opaque, in case somebody
would try toString() on it:
http://forum.dlang.org/post/ksc2ln$f1i$1...@digitalmars.com
I have been to lazy to bring this topic up on the main newsgroup before
opening an enhancement request.
Ali
Re: apply function to parameters
On Tuesday, 6 August 2013 at 14:44:18 UTC, bearophile wrote: Take a look at std.typetuple.staticMap staticMap works with types, and I don't know how it can help.
Re: apply function to parameters
On Tuesday, 6 August 2013 at 15:51:28 UTC, Jack Applegame wrote: On Tuesday, 6 August 2013 at 14:44:18 UTC, bearophile wrote: Take a look at std.typetuple.staticMap staticMap works with types, and I don't know how it can help. Not really. Anything that can be provided to template argument list can be stored in TypeTuple and thus processed by staticMap. Name is very confusing here.
Re: X11 XSynchronize() definition in D
On 08/06/2013 08:46 AM, Ali Çehreli wrote:
On 08/06/2013 03:22 AM, David wrote: struct Display
{}
D supports opaque structs/pointers
struct Display;
Now Display has to be used as pointer only or the compiler complains
e.g. about
Display display;
Yes and I am sure that is how Xlib.d has it.
However, remembering a limitation that we have discovered a couple of
weeks ago, I intentionally did not make it opaque, in case somebody
would try toString() on it:
I am confused and being confusing... I think nobody should apply
toString() on an opaque type as it is supposed to dereference the actual
object.
http://forum.dlang.org/post/ksc2ln$f1i$1...@digitalmars.com
I will continue on that thread.
Ali
Re: apply function to parameters
On Tuesday, 6 August 2013 at 16:03:07 UTC, Dicebot wrote:
On Tuesday, 6 August 2013 at 15:51:28 UTC, Jack Applegame wrote:
On Tuesday, 6 August 2013 at 14:44:18 UTC, bearophile wrote:
Take a look at std.typetuple.staticMap
staticMap works with types, and I don't know how it can help.
Not really. Anything that can be provided to template argument
list can be stored in TypeTuple and thus processed by
staticMap. Name is very confusing here.
Yes. Types, literals and aliases. But this doesn't help.
I wrote very ugly, but working solution. I don't like it, but I
can't invent something better. :(
auto apply(alias p, alias f, Args...)(Args args) {
auto impl(uint num, Head, Tail...)(Head head, Tail tail) {
static if(num == 0) return p(head, tail);
else return impl!(num - 1)(tail, f(head));
}
return impl!(args.length)(args);
}
apply!(fun1, fun2)(arg1, arg2, ...) === fun1(fun2(arg1),
fun2(arg2), ...)
offtop: Dicebot, do you speak russian?
Re: apply function to parameters
On 08/06/13 18:03, Dicebot wrote:
On Tuesday, 6 August 2013 at 15:51:28 UTC, Jack Applegame wrote:
On Tuesday, 6 August 2013 at 14:44:18 UTC, bearophile wrote:
Take a look at std.typetuple.staticMap
staticMap works with types, and I don't know how it can help.
Not really. Anything that can be provided to template argument list can be
stored in TypeTuple and thus processed by staticMap. Name is very confusing
here.
The problem is more that staticMap requires a *template*, not a
function. Another one is that doing it like that (ie storing the
intermediate results in a tuple or struct) creates unnecessary
copies - which isn't really an issue for small PODs, because the
compiler optimizes most of the overhead away, but can have a
significant cost when handling types w/ nontrivial cpctors etc.
Anyway, there are several ways to do this in D. One example:
void foo(Args...)(Args args) {
mixin(evalExpMap!(q{ somefunc(%...); }, q{ process(%s) }, args));
// == `somefunc(process(args[0]), process(args[1]), etc);`
}
// or
void foo(Args...)(Args args) {
auto result = mixin(evalExpMap!(q{ somefunc(%...) }, q{ process(%s) },
args));
//...
}
// and the helper:
template evalExpMap(string C, string F, A...) {
enum evalExpMap = {
import std.array, std.conv;
string s, l;
static if (is(typeof(A))) alias B = typeof(A);
else alias B = A;
foreach (I, _; B) {
auto r = replace( replace(F, %s, A[I].stringof),
%d, to!string(I));
l ~= (I?, :) ~ r;
s ~= r ~ ;\n;
}
return replace(replace(C, %...;, s), %..., l);
}();
}
Not as simple as the C++ equivalent. But not that much more
complicated and *much* more powerful.
artur
Re: Logging and tracing in D
On Tuesday, 6 August 2013 at 04:35:39 UTC, Andre Artus wrote:
What is the recommended approach for adding logging and tracing
to D apps?
Is there a library for it?
custom very simple yet powerful logging can be achieved with
templates and debug specifier, something like this:
module logger;
import std.datetime;
import std.stdio : writefln;
template log(T) {
auto timeString = Clock.currTime().toISOExtString();
writefln(log message from(%s)[+%s]: %s, __FUNCTION__,
timeString, T);
}
then in ur code just place with debug specifier:
import logger;
void main {
debug log!my stuff;
}
and you get pretty formatted message in console(add log file
writer if needed), and you get smart logging for free, in that
way it will be generated only for debug mode(in release it will
be skipped because of debug specifier).
Re: Logging and tracing in D
-- snip-- and you get pretty formatted message in console(add log file writer if needed), and you get smart logging for free, in that way it will be generated only for debug mode(in release it will be skipped because of debug specifier). Thanks, can I take it that there is no official library for this kind of thing then? I would think it generally useful. Perhaps it can be considered for inclusion into Phobos.
Re: Logging and tracing in D
On Tue, Aug 06, 2013 at 07:22:11PM +0200, Andre Artus wrote: -- snip-- and you get pretty formatted message in console(add log file writer if needed), and you get smart logging for free, in that way it will be generated only for debug mode(in release it will be skipped because of debug specifier). Thanks, can I take it that there is no official library for this kind of thing then? I would think it generally useful. Perhaps it can be considered for inclusion into Phobos. This is strange. I clearly remember some time ago that there was a logging module in the Phobos review queue. But after the initial feedback, I haven't heard anything from it since. What's going on? Has it been abandoned? T -- Those who've learned LaTeX swear by it. Those who are learning LaTeX swear at it. -- Pete Bleackley
Re: Logging and tracing in D
Am 06.08.2013 19:22, schrieb Andre Artus: -- snip-- and you get pretty formatted message in console(add log file writer if needed), and you get smart logging for free, in that way it will be generated only for debug mode(in release it will be skipped because of debug specifier). Thanks, can I take it that there is no official library for this kind of thing then? I would think it generally useful. Perhaps it can be considered for inclusion into Phobos. There is std.log (proposed), it doesn't work, I don't like its API. I wrote my own logger (consider it MIT licensed) https://github.com/Dav1dde/BraLa/blob/master/brala/utils/log.d I am not 100% happy how it turned out, but I haven't come around to change it, but it works pretty well.
Re: Logging and tracing in D
David wrote: Am 06.08.2013 19:22, schrieb Andre Artus: -- snip-- and you get pretty formatted message in console(add log file writer if needed), and you get smart logging for free, in that way it will be generated only for debug mode(in release it will be skipped because of debug specifier). Thanks, can I take it that there is no official library for this kind of thing then? I would think it generally useful. Perhaps it can be considered for inclusion into Phobos. There is std.log (proposed), it doesn't work, I don't like its API. I take it that it hasn't been documented yet, at least I could not find it on dlang.org. David: I wrote my own logger (consider it MIT licensed) https://github.com/Dav1dde/BraLa/blob/master/brala/utils/log.d I am not 100% happy how it turned out, but I haven't come around to change it, but it works pretty well. Cool, thanks, I'll check it out.
Re: Logging and tracing in D
On Tue, Aug 06, 2013 at 08:54:48PM +0200, Andre Artus wrote: David wrote: Am 06.08.2013 19:22, schrieb Andre Artus: -- snip-- and you get pretty formatted message in console(add log file writer if needed), and you get smart logging for free, in that way it will be generated only for debug mode(in release it will be skipped because of debug specifier). Thanks, can I take it that there is no official library for this kind of thing then? I would think it generally useful. Perhaps it can be considered for inclusion into Phobos. There is std.log (proposed), it doesn't work, I don't like its API. I take it that it hasn't been documented yet, at least I could not find it on dlang.org. [...] Sounds like it's not merged into the official codebase yet. T -- Always remember that you are unique. Just like everybody else. -- despair.com
Re: Getting number of messages in MessageBox
06-Aug-2013 03:18, Marek Janukowicz пишет: I'm using std.concurrency message passing and I'd like to check which thread might be a bottleneck. The easiest would be check number of messages piled up for each of them, but I could not find a way to do that. Is it possible? Every detail about MessageBox seems to be hidden... This is sadly intentional. The reasons must be due to some efficient concurrent queues not being able to produce reliable item count if at all. However this seems at odds with setMaxMailboxSize ... -- Dmitry Olshansky
Re: Logging and tracing in D
Am 06.08.2013 20:54, schrieb Andre Artus: David wrote: Am 06.08.2013 19:22, schrieb Andre Artus: -- snip-- and you get pretty formatted message in console(add log file writer if needed), and you get smart logging for free, in that way it will be generated only for debug mode(in release it will be skipped because of debug specifier). Thanks, can I take it that there is no official library for this kind of thing then? I would think it generally useful. Perhaps it can be considered for inclusion into Phobos. There is std.log (proposed), it doesn't work, I don't like its API. I take it that it hasn't been documented yet, at least I could not find it on dlang.org. It's currently in the review queue: http://wiki.dlang.org/Review_Queue but marked on hold/suspended.
Re: Logging and tracing in D
-- snip -- I take it that it hasn't been documented yet, at least I could not find it on dlang.org. It's currently in the review queue: http://wiki.dlang.org/Review_Queue but marked on hold/suspended. Thanks, I'll check it out later.
Is it possible using reflection or similar to extract only public method names from classes?
Is it possible using reflection or similar to extract only public method names from classes? I'm thinking how i would go about writing a unit test/mocking framework, investigating how i can gather information about such things before i manipulate them.
Re: Getting number of messages in MessageBox
On Aug 6, 2013, at 1:27 PM, Dmitry Olshansky dmitry.o...@gmail.com wrote: 06-Aug-2013 03:18, Marek Janukowicz пишет: I'm using std.concurrency message passing and I'd like to check which thread might be a bottleneck. The easiest would be check number of messages piled up for each of them, but I could not find a way to do that. Is it possible? Every detail about MessageBox seems to be hidden... This is sadly intentional. The reasons must be due to some efficient concurrent queues not being able to produce reliable item count if at all. However this seems at odds with setMaxMailboxSize ... The lack of a function to get the current mailbox size is mostly an oversight. It would be easy to return the same message count used by setMaxMailboxSize. This isn't an exact count, since that would be inefficient as you say, but it's a reasonable approximation. So I wouldn't use the returned message count as a pivotal part of a protocol design, for example, but it would be fine for determining whether a consumer is being overwhelmed by requests. That said, with the possible exception of setMaxMailboxSize allowing one thread to affect the behavior of another thread's mailbox, I think the current functionality should all extend to interprocess messaging without alteration. I'm not sure that this could be done for a getMailboxSize call. Certainly not with any semblance of efficiency anyway. But perhaps it's reasonable to have some subset of functionality that only works on local threads so long as the core messaging API doesn't have such limitations.
Re: Logging and tracing in D
On Tuesday, 6 August 2013 at 18:54:50 UTC, Andre Artus wrote: David wrote: There is std.log (proposed), it doesn't work, I don't like its API. I take it that it hasn't been documented yet, at least I could not find it on dlang.org. http://wiki.dlang.org/Review_Queue
Re: Is it possible using reflection or similar to extract only public method names from classes?
Gary Willoughby wrote: Is it possible using reflection or similar to extract only public method names from classes? I'm thinking how i would go about writing a unit test/mocking framework, investigating how i can gather information about such things before i manipulate them. See traits: http://dlang.org/traits.html Look for: getProtection, getVirtualFunctions, getVirtualMethods. -- Marek Janukowicz
Re: Is it possible using reflection or similar to extract only public method names from classes?
On Tue, Aug 06, 2013 at 11:41:35PM +0200, Gary Willoughby wrote:
Is it possible using reflection or similar to extract only public
method names from classes? I'm thinking how i would go about writing
a unit test/mocking framework, investigating how i can gather
information about such things before i manipulate them.
The following code demonstrates how you can do this:
import std.stdio;
class Base {
private int x;
public int y;
this() {}
private void privMethod() {}
public void method() {}
}
class Derived : Base {
public override void method() {}
public void derivedMethod() {}
private void privDerivedMethod() {}
}
void showAllMethods(C)(C obj) {
writeln(All members:);
foreach (field; __traits(allMembers, C)) {
static if (is(typeof(__traits(getMember, obj, field)) T
== function)) {
auto prot = __traits(getProtection,
__traits(getMember, obj, field));
writefln(\t(%s) %s, prot, field);
}
}
}
void showDerivedMethods(C)(C obj) {
writeln(\nDerived members:);
foreach (field; __traits(derivedMembers, C)) {
static if (is(typeof(__traits(getMember, obj, field)) T
== function)) {
auto prot = __traits(getProtection,
__traits(getMember, obj, field));
writefln(\t(%s) %s, prot, field);
}
}
}
string[] getPublicMethods(C)(C obj) {
string[] methods;
foreach (field; __traits(allMembers, C)) {
static if (is(typeof(__traits(getMember, obj, field))
== function)
__traits(getProtection,
__traits(getMember, obj, field)) == public)
{
methods ~= field;
}
}
return methods;
}
void main() {
auto d = new Derived();
showAllMethods(d);
showDerivedMethods(d);
writeln(All public methods:);
writeln(getPublicMethods(d));
}
The output is:
All members:
(public) method
(public) derivedMethod
(private) privDerivedMethod
(public) __ctor
(private) privMethod
(public) toString
(public) toHash
(public) opCmp
(public) opEquals
(public) factory
Derived members:
(public) method
(public) derivedMethod
(private) privDerivedMethod
(public) __ctor
All public methods:
[method, derivedMethod, __ctor, toString, toHash, opCmp,
opEquals, factory]
Hope this helps!
T
--
Designer clothes: how to cover less by paying more.
Re: Which option is faster...
On Tuesday, 6 August 2013 at 14:49:42 UTC, Andre Artus wrote:
On Tuesday, 6 August 2013 at 12:32:13 UTC, jicman wrote:
On Tuesday, 6 August 2013 at 04:10:57 UTC, Andre Artus wrote:
On Monday, 5 August 2013 at 13:59:24 UTC, jicman wrote:
Greetings!
I have this code,
foreach (...)
{
if (std.string.tolower(fext[0]) == doc ||
std.string.tolower(fext[0]) == docx ||
std.string.tolower(fext[0]) == xls ||
std.string.tolower(fext[0]) == xlsx ||
std.string.tolower(fext[0]) == ppt ||
std.string.tolower(fext[0]) == pptx)
continue;
}
foreach (...)
{
if (std.string.tolower(fext[0]) == doc)
continue;
if (std.string.tolower(fext[0]) == docx)
continue;
if (std.string.tolower(fext[0]) == xls)
continue;
if (std.string.tolower(fext[0]) == xlsx)
continue;
if (std.string.tolower(fext[0]) == ppt)
continue;
if (std.string.tolower(fext[0]) == pptx)
continue;
...
...
}
thanks.
josé
What exactly are you trying to do with this? I get the
impression that there is an attempt at local optimization
when broader approach could lead to better results.
For instance. Using the OS's facilities to filter (six
requests, one each for *.doc, *.docx) could actually end
up being a lot faster.
If you could give more detail about what you are trying to
achieve then it could be possible to get better results.
The files are in a network drive and doing a list foreach
*.doc, *.docx, etc. will be more expensive than getting the
list of all the files at once and then processing them
accordingly.
Again, what are you trying to achieve?
Your statement is not necessarily true, for a myriad of
reasons, but it entirely depends on what you want to do.
I would reiterate Dennis Luehring's reply, why are you not
benching? It seems like you are guessing at what the problems
are, that's hardly ever useful.
One of the first rules of network optimization is to reduce
the amount od data, that normally means filtering.at the
server, the next thing is coarse grained is better than fine
(BOCTAOE/L).
It's a long story and I will return in a few months and give you
the whole story, but right now, time is not on my side. I have
answers for all the questions you folks have asked, and I
appreciate all the input. I have the answer that I was looking
for, so in a few months, I will come back and explain the whole
story. Thanks for all the response and suggestions.
jic
