Re: Is there an efficient byte buffer queue?
On Monday, 8 October 2018 at 10:31:33 UTC, Nicholas Wilson wrote: Try searching for "circular buffer". I'm sure http://code.dlang.org/packages/iopipe has them in some form but I can't find them with a cursory search. https://github.com/dlang-community/containers/blob/master/src/containers/cyclicbuffer.d
Re: Why are 2-D arrays reversed?
On Wednesday, October 10, 2018 4:26:40 PM MDT Chris Katko via Digitalmars-d-
learn wrote:
> On Wednesday, 10 October 2018 at 16:00:42 UTC, Steven
>
> Schveighoffer wrote:
> > On 10/10/18 9:22 AM, Chris Katko wrote:
> >> int[][] data =
> >>
> >> [
> >> [1, 0, 1, 0, 0],
> >> [1, 0, 1, 0, 0],
> >> [1, 0, 1, 1, 1],
> >> [1, 0, 0, 1, 0],
> >> [5, 1, 1, 1, 0]
> >> ];
> >>
> >> when drawn with data[i][j], prints the transpose of "data":
> >>
> >> [1, 1, 1, 1, 5]
> >> [0, 0, 0, 0, 1]
> >> [1, 1, 1, 0, 1]
> >> [0, 0, 1, 1, 1]
> >> [0, 0, 1, 0, 0]
> >>
> >> So, if I flip [i][j] and print a row of "j's", it'll be
> >> correct. It's very confusing and counter-intuitive to have to
> >> remember to swap i and j every time I use an array.
> >>
> >> I guess when I load data from files, the i/j are already
> >> swapped and stay consistent, but when using an array in source
> >> code, they have to be flipped.
> >
> > I'm not sure what code you are using, but it prints out just
> > fine for me:
> >
> > https://run.dlang.io/is/hrA0tj
> >
> > -Steve
>
> Ah, here's a simple example:
>
> int[][] data3 =
> [
> [1, 0, 1, 0, 0],
> [1, 0, 1, 0, 0],
> [1, 0, 1, 1, 1],
> [1, 0, 0, 1, 0],
> [5, 1, 1, 1, 0]
> ];
>
> for(int i = 0; i < 5; i++)
> {
> for(int j = 0; j < 5; j++)
> {
> write(data4[i][j]," ");
> }
> writeln();
> }
>
>1 0 1 0 0
>1 0 1 0 0
>1 0 1 1 1
>1 0 0 1 0
>5 1 1 1 0
>
> I have to draw j's first. I have to iterate through the
> "y"/columns/j to get the the "x's" first.
>
> I mean, I guess it makes sense if the outer-most array indexer
> refers to the inner-most "element".
>
> Wait, this IS the same as C, isn't it? So maybe this is just a
> "new" problem for me since I rarely-if-ever use hardcoded
> arrays...
>
> Maybe my brain is just melting.
The situation is bascially the same as C, though trying to make the type
syntax more consistent by putting it all on the left-hand side of the
variable has made things more confusing. The types read basically the same
as in C. The primary difference is that in D, the static array sizes go with
the type and not the variable name, which means that they're on the
left-hand side rather than the right. So, you get
int[5][4] arr;
instead of
int arr[4][5];
In both cases, the type is read outward from the variable name (which is
basically how the compiler reads types in both C and D, though understanding
that is more critical in C because of C's function pointer syntax). It's
just that in the D case, this then seems backwards, because when you then
index the array, the left index has $ of 4 and the right has $ of 5, which
is the reverse of the order in the declaration, whereas in C, the order
matches, because the sizes went on the right-hand side. One sort of
consistency was traded for another. With dynamic arrays, the sizes are
always given on the right-hand side, so you don't get that reversal. So,
what D does is reasonably consistent and matches C in terms of how types are
read, but it does end up being annoyingly hard to wrap your head around,
because the result is that the sizes of multi-dimensional, static arrays are
then declared in the opposite order from the order that they're accessed in.
If it weren't for the fact that D does out-of-bounds checking for all array
accesses in @safe code or when -release is not used, it would likely to be a
huge problem with such arrays in practice. Fortunately, since the checks are
almost always in place, the inevitable mistakes are usually quickly caught.
- Jonathan M Davis
Re: static foreach
On 10/10/2018 04:03 PM, James Japherson wrote:> Says that it cannot
interpret X(the class that contains the static> opApply).
It's a bit hard to diagnose the problem you're getting using that
function when we don't have the code that uses it. Or the context that's
referenced with the foreach loop there. You might want to post a larger
segment of code and the entire error message.
The error I'm seeing that might be related is: opApply is a static
member of the type. So part of the function (after mixins) reads:
dg(X.opApply);
This attempts to call X.opApply with no arguments and pass the result to
dg. But X.opApply requires an argument.
You probably want to add a `is(typeof(mixin("X." ~ m)) == cPiece)` in there.
static foreach
I have a static opApply in a class and I need to iterate over all
the members statically using foreach
// Iterates over all members
static int opApply(int delegate(cPiece) dg)
{
alias T = typeof(this);
foreach (m; __traits(derivedMembers, T))
{
import std.traits : hasStaticMember;
static if (hasStaticMember!(T, m))
{
mixin("dg(X."~m~");");
}
}
return 0;
}
This is not a problem using foreach.
But when I use static foreach it fails!!!
Says that it cannot interpret X(the class that contains the
static opApply).
the opApply is static, it does everything at compile time, so why
can't the foreach be statically used?
The whole point of using opApply was so that I wouldn't have to
write all that code each time and I could just iterate over class
members when I need to.
Using . notation abstractly
struct Dispatcher(Base...)
{
static auto opDispatch(string name, T...)(T vals)
{
pragma(msg, " - ", name);
return Dispatcher!(Base, name).init;
}
}
struct Dispatch
{
alias X = Dispatcher!void;
alias X this;
}
pragma(msg, Dispatch.A.B.C, " - ", typeof(Dispatch.A.B.C));
CT Output:
- A
- B
- C
Dispatcher() - Dispatcher!(void, "A", "B", "C")
The idea is one can do
Dispatch.Left.Right.A.B.C;
and it will sequentially handle all the indirections regardless
of how many and return an object that encodes the path. (which
then can be collapsed down to a single string).
Ultimately some action can then be taken on the path.
The point of all this is because D does not allow nesting of enums
which allows for nice use of . to separate hiearchies:
enum A
{
enum B
{
X,
}
}
A.B.X, rather than having to have one large flat enum and do
things like A_B_X.
I know one can use structs but it is messy and not general enough.
Dispatch.A.B.X
can be used such as
struct A
{
alias Dispatch this;
}
A.B.X
but it requires more machinery to setup.
The purpose is mainly to be able to hijack the `.` notation to
create nice separations visually like we do for indirection but
allow it to mean many different things.
One of the problems is connecting it with actual code that does
something depending on the path in a way that is general enough
to be used for a wide variety of problems.
Any ideas on how this could be done?
Re: Why are 2-D arrays reversed?
On Wednesday, 10 October 2018 at 16:00:42 UTC, Steven
Schveighoffer wrote:
On 10/10/18 9:22 AM, Chris Katko wrote:
int[][] data =
[
[1, 0, 1, 0, 0],
[1, 0, 1, 0, 0],
[1, 0, 1, 1, 1],
[1, 0, 0, 1, 0],
[5, 1, 1, 1, 0]
];
when drawn with data[i][j], prints the transpose of "data":
[1, 1, 1, 1, 5]
[0, 0, 0, 0, 1]
[1, 1, 1, 0, 1]
[0, 0, 1, 1, 1]
[0, 0, 1, 0, 0]
So, if I flip [i][j] and print a row of "j's", it'll be
correct. It's very confusing and counter-intuitive to have to
remember to swap i and j every time I use an array.
I guess when I load data from files, the i/j are already
swapped and stay consistent, but when using an array in source
code, they have to be flipped.
I'm not sure what code you are using, but it prints out just
fine for me:
https://run.dlang.io/is/hrA0tj
-Steve
Ah, here's a simple example:
int[][] data3 =
[
[1, 0, 1, 0, 0],
[1, 0, 1, 0, 0],
[1, 0, 1, 1, 1],
[1, 0, 0, 1, 0],
[5, 1, 1, 1, 0]
];
for(int i = 0; i < 5; i++)
{
for(int j = 0; j < 5; j++)
{
write(data4[i][j]," ");
}
writeln();
}
1 0 1 0 0
1 0 1 0 0
1 0 1 1 1
1 0 0 1 0
5 1 1 1 0
I have to draw j's first. I have to iterate through the
"y"/columns/j to get the the "x's" first.
I mean, I guess it makes sense if the outer-most array indexer
refers to the inner-most "element".
Wait, this IS the same as C, isn't it? So maybe this is just a
"new" problem for me since I rarely-if-ever use hardcoded
arrays...
Maybe my brain is just melting.
Re: Copy parameters from function passed as an alias
On Wednesday, 10 October 2018 at 12:10:06 UTC, bauss wrote: On Wednesday, 10 October 2018 at 08:16:11 UTC, Kagamin wrote: How do you want to use parameter names of an arbitrary function? What I want to do is pass a function to a template and that template creates a function with the same parameters as the function passed to it, if it wasn't clear. I can already do that if you see my examples, BUT it's not pretty. I suppose the question is, why is your first example inadequate? In other words, why is it important that the parameters of the generated function have the same names as the original parameters?
Re: typo mapNode[6]* exits; instead of mapNode*[6] exits; but whats it mean ?
On Wednesday, 10 October 2018 at 13:36:20 UTC, Simen Kjærås wrote: mapNode[6]* can be read right-to-left as 'a pointer to an array right... hence the failed attempt at an array copy... now I understand...
Re: Why are 2-D arrays reversed?
On 10/10/18 9:22 AM, Chris Katko wrote: int[][] data = [ [1, 0, 1, 0, 0], [1, 0, 1, 0, 0], [1, 0, 1, 1, 1], [1, 0, 0, 1, 0], [5, 1, 1, 1, 0] ]; when drawn with data[i][j], prints the transpose of "data": [1, 1, 1, 1, 5] [0, 0, 0, 0, 1] [1, 1, 1, 0, 1] [0, 0, 1, 1, 1] [0, 0, 1, 0, 0] So, if I flip [i][j] and print a row of "j's", it'll be correct. It's very confusing and counter-intuitive to have to remember to swap i and j every time I use an array. I guess when I load data from files, the i/j are already swapped and stay consistent, but when using an array in source code, they have to be flipped. I'm not sure what code you are using, but it prints out just fine for me: https://run.dlang.io/is/hrA0tj -Steve
Re: Home Brew dmd update 2.082
On Sunday, 7 October 2018 at 13:24:39 UTC, Joel wrote: It's been a over a month, and there still isn't an update for dmd 2.082 on macOS using Home Brew?! I get this (with 'brew upgrade dmd'): Error: dmd 2.081.2 already installed Yeah... :( https://github.com/Homebrew/homebrew-core/blob/master/Formula/dmd.rb
Re: typo mapNode[6]* exits; instead of mapNode*[6] exits; but whats it mean ?
On Wednesday, 10 October 2018 at 13:24:42 UTC, Codifies wrote:
I'm not sure I understand what mapNode[6]* means! (the second
version is what I wanted an array of 6 pointers)
oddly when assigning a null to one element of the array it
cause an error as it was trying to do an array copy... so
what's going on and what does that definition actually mean ?
mapNode[6]* can be read right-to-left as 'a pointer to an array
of 6 mapNodes'.
For simplicity, let's use int instead of mapNode:
unittest {
int[6]* p;
int[6] arr;
p =
(*p)[0] = 1;
(*p)[1] = 2;
(*p)[2] = 3;
(*p)[3] = 4;
(*p)[4] = 5;
(*p)[5] = 6;
assert(arr == [1,2,3,4,5,6]);
}
--
Simen
Re: Why are 2-D arrays reversed?
On Wednesday, 10 October 2018 at 13:22:41 UTC, Chris Katko wrote: int[][] data = [ [1, 0, 1, 0, 0], [1, 0, 1, 0, 0], [1, 0, 1, 1, 1], [1, 0, 0, 1, 0], [5, 1, 1, 1, 0] ]; when drawn with data[i][j], prints the transpose of "data": [1, 1, 1, 1, 5] [0, 0, 0, 0, 1] [1, 1, 1, 0, 1] [0, 0, 1, 1, 1] [0, 0, 1, 0, 0] So, if I flip [i][j] and print a row of "j's", it'll be correct. It's very confusing and counter-intuitive to have to remember to swap i and j every time I use an array. I guess when I load data from files, the i/j are already swapped and stay consistent, but when using an array in source code, they have to be flipped. What you actually have there is an array of arrays, or a jagged array, and not a 2D, or multidimensional, array. If you dig into it, it's consistent with how array syntax works with all types. Consider the basics: int i; int[] intArray; The type of `i` is `int`. If I want an array of ints, I put the brackets next to the type. The type of `intArray` is `int[]`, but it contains elements of type `int`. We can visualize it with parens: (int)[]; This indicates that `int` is the element type. We can apply the same rules to int[][]: int[] singleArr;// type is int[], element type int int[][] doubleArr; // type is int[][], element type ? Again, using parens we cans the element type of `doubleArr`: (int[])[]; So singleArr[0] returns the first `int`, and doubleArr[][0] returns the first int[]. Consistent. So the syntax you are used to in C or C++ is /backwards/ in D.
typo mapNode[6]* exits; instead of mapNode*[6] exits; but whats it mean ?
I'm not sure I understand what mapNode[6]* means! (the second version is what I wanted an array of 6 pointers) oddly when assigning a null to one element of the array it cause an error as it was trying to do an array copy... so what's going on and what does that definition actually mean ?
Why are 2-D arrays reversed?
int[][] data = [ [1, 0, 1, 0, 0], [1, 0, 1, 0, 0], [1, 0, 1, 1, 1], [1, 0, 0, 1, 0], [5, 1, 1, 1, 0] ]; when drawn with data[i][j], prints the transpose of "data": [1, 1, 1, 1, 5] [0, 0, 0, 0, 1] [1, 1, 1, 0, 1] [0, 0, 1, 1, 1] [0, 0, 1, 0, 0] So, if I flip [i][j] and print a row of "j's", it'll be correct. It's very confusing and counter-intuitive to have to remember to swap i and j every time I use an array. I guess when I load data from files, the i/j are already swapped and stay consistent, but when using an array in source code, they have to be flipped.
Re: Copy parameters from function passed as an alias
On Wednesday, 10 October 2018 at 08:16:11 UTC, Kagamin wrote: How do you want to use parameter names of an arbitrary function? What I want to do is pass a function to a template and that template creates a function with the same parameters as the function passed to it, if it wasn't clear. I can already do that if you see my examples, BUT it's not pretty.
Re: Process Pipes
On Tuesday, 9 October 2018 at 09:15:09 UTC, Gorker wrote: Hi all, I'm on macOS 10.11.6 with dmd 2.081.2 and I've a problem with std.process. --- gork ():foo gorker$ gcc -c -Iinclude -o foo.cpp.o src/foo.cpp In file included from src/foo.cpp:2: include/foo/foo.hpp:22:10: warning: scoped enumerations are a C++11 extension [-Wc++11-extensions] enum class foo_event_type_t ^ 56 warnings and 9 errors generated. --- No output, (zero bytes) in stdout. If I use standard process to collect both stream with: --- auto processPipes = pipeProcess(args, Redirect.all, null, Config.none, workDir); foreach (c; pipes.stdout.byChunk(100)) writeln(cast(string) c); // <<< it halts here: stdout file is empty, but not EOF foreach (c; pipes.stderr.byChunk(100)) writeln(cast(string) c); --- Everything is fine if I don't redirect the stderr to a pipe. Suggestions? If you want to use asynch io - you'll have to fork and use NONBLOCK output on the file descriptor. I wrote this years ago (not sure if it still compiles tbh, but it should) https://github.com/grogancolin/dexpect Specifically this block should help you: https://github.com/grogancolin/dexpect/blob/master/source/dexpect.d#L343-L352
Re: Process Pipes
On Wednesday, 10 October 2018 at 09:16:43 UTC, Gorker wrote:
On Wednesday, 10 October 2018 at 08:31:36 UTC, Kagamin wrote:
Maybe read them with parallelism?
http://dpldocs.info/experimental-docs/std.parallelism.parallel.2.html
thanks, but I'd rather avoid having to use threads just for
this reason.
some other suggestion?
This might be a way to do it under Linux / Posix systems (it
reads byte by byte), adapted from my web server which uses it to
read the output from php/perl/cgi scripts:
https://github.com/DannyArends/DaNode/blob/master/danode/process.d
It uses fcntl to make sure the pipe is non-blocking
you can read 1 byte from the stdout pipe, then 1 byte from stderr
pipe
bool nonblocking(ref File file) {
version(Posix) {
return(fcntl(fileno(file.getFP()), F_SETFL, O_NONBLOCK) !=
-1);
}else{
return(false);
}
}
int readpipe(ref Pipe pipe, int verbose = NORMAL){
File fp = pipe.readEnd;
try{
if(fp.isOpen()){
if(!nonblocking(fp) && verbose >= DEBUG) writeln("[WARN]
unable to create nonblocking pipe for command");
return(fgetc(fp.getFP()));
}
}catch(Exception e){
writefln("[WARN] Exception during readpipe command: %s",
e.msg);
fp.close();
}
return(EOF);
}
pStdIn = File(inputfile, "r");
pStdOut = pipe();
pStdErr = pipe();
auto cpid = spawnShell(command, pStdIn, pStdOut.writeEnd,
pStdErr.writeEnd, null);
while(true){
ch = readpipe(pStdOut);
outbuffer.put(cast(char)ch);
ch = readpipe(pStdErr);
errbuffer.put(cast(char)ch);
}
Hope this works for your usecase
Re: Process Pipes
On Wednesday, 10 October 2018 at 08:31:36 UTC, Kagamin wrote: Maybe read them with parallelism? http://dpldocs.info/experimental-docs/std.parallelism.parallel.2.html thanks, but I'd rather avoid having to use threads just for this reason. some other suggestion?
Re: Process Pipes
Maybe read them with parallelism? http://dpldocs.info/experimental-docs/std.parallelism.parallel.2.html
Re: Can i watch folders/files for changes with D language?
On 2018-10-09 19:20, Ephrahim wrote: I intend to make this a command line tool for a start, but i'll need a GUI sooner or later. So i also need help pointing me to the best available GUI library D has. It's difficult to specifying a single best GUI library. But I'll mention DWT [1] [2]. It has a native look and feel and works on Windows and Linux (GTK). [1] http://code.dlang.org/packages/dwt [2] https://github.com/d-widget-toolkit/dwt -- /Jacob Carlborg
Re: Copy parameters from function passed as an alias
How do you want to use parameter names of an arbitrary function?
Re: Process Pipes
On Wednesday, 10 October 2018 at 08:02:29 UTC, Kagamin wrote: stderr buffer is full (it's about 8kb or so) and gcc waits when you read from it. Thank you for your kind reply, How to just try to read from stdout (not blocking), and then try to read from stderr (not blocking)? I mean, how to check both pipes for data? As an alternative, how to raise the 8kb limit?
Re: Process Pipes
stderr buffer is full (it's about 8kb or so) and gcc waits when you read from it.
Re: Can i watch folders/files for changes with D language?
On Tue, 2018-10-09 at 17:20 +, Ephrahim via Digitalmars-d-learn wrote: > Hi Everyone, i'm planning on developing a software for > synchronizing folder contents across multiple computers. The > software will evolve very quickly into virtual Remote Desktop > Access system. > So i've been considering C++ for this, its the best in the market > of all things fast at the moment (Considering the availability of > tools and docs). But i hate just two things in the language, > (.cpp + .h files) and no "easy" centralized package manager. > So i'm definitely considering D and Python now, but D seems to > satisfy my needs as per this software. I've developed very good > custom server for hardware before, and it performed very well. > So i need your help guys, can you point me to any documentation > or libraries i can use to watch files/folders for changes > (delete, edit, new content)? Conan is the up and coming centralised package management system for C++. C++ may, or may not, get modules (and so remove the .cpp/.h split) sometime before the heat death of the universe. You should add Rust to the list of options I believe. Not sure whether Go should be added as well, probably Yes. Python, D, Rust, and Go, all have bindings the the various file watching facilities in the various operating systems. > I intend to make this a command line tool for a start, but i'll > need a GUI sooner or later. So i also need help pointing me to > the best available GUI library D has. It is really a question of which GUI framework you want to use. This is a situation where a bit of forward planning will help avoid having to reimplement or hack in silly ways. The two obvious candidates are Qt and GTK if you want to be cross- platform. This then leads to the question which programming languages have good bindings to the frameworks. I am more or less in the GTK camp now having more or less given up on Qt, however Qt remains a very good choice. D, Python, and Rust have excellent bindings to GTK. Go has a good binding. C++ binding to GTK is not bad, but I prefer the D and Rust ones. Python has an excellent binding to Qt (use PySide2). Obviously C++ has an excellent binding to Qt since Qt is a C++ library. I have not properly investigated D and Rust bindings to Qt. The Big Question™ is whether to use QML or not. I get the feeling the answer is yes you probably should. The Python and Go binding for using QML are good, I haven't tried D, Rust, or C++. […] -- Russel. === Dr Russel Winder t: +44 20 7585 2200 41 Buckmaster Roadm: +44 7770 465 077 London SW11 1EN, UK w: www.russel.org.uk signature.asc Description: This is a digitally signed message part
