write multiple lines without \n with writeln
In dco source code I have found:
void ShowUsage()
{
writeln(
dco build tool ~ strVersion ~
written by FrankLIKE.
Usage:
dco [switches...] files...
for example: dco
or: dco app.d
build for dfl2: dco
}
I do not see here any \n. Why this code is output all one by
line, and not in single line?
Why my code:
writeln(App name: ~ appName ~
App version: ~ appVersion ~
To see help please use -h\\-help option);
writeln(args);
output:
App name:CoolAppApp version:0.0.1To see help please use -h\-help
option[.\\app1
.exe]
Compiler error with slices, .dup and ref Parameter
module a;
void init (ref string[] argv) { }
void main(string[] args) {
init(args); //ok
auto y = args[1..$];
init(y); //ok
auto x = args.dup;
init(x); //ok
init(args[1..$]); // Error: function a.init (ref string[]
argv) is not callable using argument types (string[])
init(args.dup); // Error: function a.init (ref string[] argv)
is not callable using argument types (string[])
}
tested with
dmd 2.066.0
ldc 0.15 beta (Frontend 2.066.1)
Similar Errors occure with int[].
Is this a bug that should be reported or is there some reason for
the errors?
I searched for an issue the bugtracker and did not find a
matching one.
The error messages are strange anyway.
Re: Compiler error with slices, .dup and ref Parameter
On 11/20/2014 12:37 AM, anynomous wrote:
module a;
void init (ref string[] argv) { }
void main(string[] args) {
init(args); //ok
auto y = args[1..$];
init(y); //ok
auto x = args.dup;
init(x); //ok
init(args[1..$]); // Error: function a.init (ref string[]
argv) is not callable using argument types (string[])
init(args.dup); // Error: function a.init (ref string[] argv)
is not callable using argument types (string[])
}
Both of the error cases are trying to pass rvalues as arguments to ref
parameters. Not possible in D even for reference to const.
Judging from the name init(), I don't think you need ref anyway.
If you really want to write a function that should take both lvalues and
rvalues, then a convenient solution is to use 'auto ref', which is
available only to templates. For that reason, you have to stick an empty
template parentheses just to make it a template:
void init()(auto ref string[] argv) { }
'auto ref' takes lvalues by reference and rvalues by copy. So, the code
will work but then if you make modifications to the parameter and it was
an rvalue to begin with, your changes will not be visible outside of the
function anyway.
So, it is more natural to use 'auto ref' in cases where you don't want
to modify the parameter. Then you use 'auto ref const':
void init()(auto ref const string[] argv) { }
Again though, you probably don't want 'ref' anyway. (?)
The error messages are strange anyway.
Agreed. In the case of assignment to rvalue, dmd is better:
a + b = 42; // Error: a + b is not an lvalue
Ali
P.S. Your question is incredibly timely. I've started writing a new
chapter titled Lvalues and Rvalues just yesterday. :)
Re: write multiple lines without \n with writeln
On Thursday, 20 November 2014 at 08:28:11 UTC, Suliman wrote:
In dco source code I have found:
void ShowUsage()
{
writeln(
dco build tool ~ strVersion ~
written by FrankLIKE.
Usage:
dco [switches...] files...
for example: dco
or: dco app.d
build for dfl2: dco
}
I do not see here any \n. Why this code is output all one by
line, and not in single line?
Why my code:
writeln(App name: ~ appName ~
App version: ~ appVersion ~
To see help please use -h\\-help option);
writeln(args);
output:
App name:CoolAppApp version:0.0.1To see help please use
-h\-help option[.\\app1
.exe]
In all string literal forms, an EndOfLine is regarded as a
single \n character.
http://dlang.org/lex.html
It's by design but is *really* annoying and should be limited to
WysiwygString literals IMO.
Auto-formatting with clang-format or astyle can mess up writeln
formatting completely.
Cheers,
uri
Re: write multiple lines without \n with writeln
uri: It's by design And it's a nice handy design. Bye, bearophile
dco how to specify Jpath?
I am playing with dco. And it's look very helpful for tiny projects. I can't understand is it's possible to add to dco.ini Jpath? I am talking about something like: dflags=-JD:\code\d\App1\source\ but when I am trying to compile code with dco it's can't find import. I looked at source code and it's look like it's do not support dflags... https://github.com/FrankLIKE/dco/tree/master/source
Re: Compiler error with slices, .dup and ref Parameter
Ali Çehreli: The error messages are strange anyway. Agreed. In the case of assignment to rvalue, dmd is better: a + b = 42; // Error: a + b is not an lvalue The error messages in the OP case can and should be improved. I suggest to take a look in Bugzilla to see if there's already an ER for it, and otherwise to add the little diagnostic ER it to Bugzilla. Bye, bearophile
Re: write multiple lines without \n with writeln
I understand it. I expect what concatenation symbol will stay new line in new line and not append it's to current: writeln( first string second ~ string ); I expect: first string second string but not: first stringsecondstring
Re: help
On 11/20/2014 3:38 PM, michael via Digitalmars-d-learn wrote:
Hello All:
when i am using std.net.curl to download a file that dosent exist on ftp
sever,my code
will get an execption like this
std.net.curl.CurlException@std\net\curl.d(3605
mailto:std.net.curl.CurlException@std\net\curl.d(3605): Remote file
not found on handle
1A8E038
0x0042EC05
0x004027F6
and then it exits,however what i want when it occers is that my
code shows an error message like
please check the url you typed blablabla not the one above,can anyone
give a hand on me ?
thanks a lot.
Michael.
try {
// call curl
} catch( CurlException ) {
// print error message
}
Re: write multiple lines without \n with writeln
Suliman:
I understand it.
I expect what concatenation symbol will stay new line in new
line and not append it's to current:
writeln(
first string
second ~
string
);
I expect:
first string
second
string
but not:
first stringsecondstring
If I compile and run this program:
void main() {
import std.stdio;
writeln(
first string
second ~
string
);
}
I see this output (and it's correct, as expected):
first stringsecondstring
Bye,
bearophile
Re: write multiple lines without \n with writeln
On Thursday, 20 November 2014 at 10:41:24 UTC, bearophile wrote: uri: It's by design And it's a nice handy design. Bye, bearophile For Wysiwyg strings I agree that it's great but I prefer C/C++/Python like behaviour for double quoted strings. I guess it's what I'm used to :) Cheers, uri
Re: Compiler error with slices, .dup and ref Parameter
On Thursday, 20 November 2014 at 09:20:34 UTC, Ali Çehreli wrote: Judging from the name init(), I don't think you need ref anyway. thanks for the explanation. I can't remove the ref because it is Main.init in gtkd. A simple solution is init(args) I just tried to remove a non-GTK argument (a filename) via slicing. This is not necessary at all...
Re: write multiple lines without \n with writeln
On Thursday, 20 November 2014 at 11:08:24 UTC, Suliman wrote: writeln( first string second ~ string ); I expect: first string second string There's no quoted newline there. You could do: writeln( first string second string); with the newlines enclosed in the quotes, then you'd get what you want. (There's no extra indenting in my example because the indent would show up too when inside quotes) But if it isn't in the quotes, newlines are basically ignored by the compiler like any other whitespace in the code.
print yyyy-mm-dd
I can't understand how to get date in format -MM-dd from Clock.currTime auto time = Clock.currTime; And what next? Could anybody give any examples?
Re: Compiler error with slices, .dup and ref Parameter
On 11/20/14 7:28 AM, anonymous wrote:
On Thursday, 20 November 2014 at 09:20:34 UTC, Ali Çehreli wrote:
Judging from the name init(), I don't think you need ref anyway.
thanks for the explanation. I can't remove the ref because it is
Main.init in gtkd.
A simple solution is init(args)
I just tried to remove a non-GTK argument (a filename) via slicing. This
is not necessary at all...
To further explain:
The only reason you would need to pass a string[] by ref is if you
wanted to modify the order/size of the array. A string[]'s data is
already passed by reference, so there is no need to ref it otherwise.
What I am guessing gtkd does, is that it processes GTK-specific
parameters from the argument string array, then *removes* those from the
arguments.
If you did *not* pass by reference, these modifications would be corrupt
when you looked at the original.
This is best illustrated by an example:
void foo()(auto ref string[] x)
{
// remove all blanks
size_t i, j;
for(i = 0, j = 0; i x.length; ++i)
{
if(x[i].length)
x[j++] = x[i];
}
x.length = j;
}
void main()
{
auto arr = [a, b, null, c, d];
foo(arr[0..$]); // pass by value
assert(arr == [a, b, c, d, d]); // oops, extra d
arr = [a, b, null, c, d];
foo(arr); // now by reference
assert(arr == [a, b, c, d]);
}
So the compiler is saving you from a mistake :)
-Steve
Re: TKd handling of custom events
On Wednesday, 19 November 2014 at 23:44:00 UTC, univacc wrote: Hello, I am using TKd to dray my linux/windows app which works very good! I would like to add a global Hotkey to my program via the Win32 API function RegisterGlobalHotkey. Is there a possibility to access Tk's event loop so that you can Handle the WM_HOTKEY message, the WinAPI sends you? Regards, univacc Nevermind. If someone has the same issue: Just create another Win32 API Window, that is hidden and let that one receive your hotkey message! Regards
Clock.currTime
I am reading the book 《D Cookbook》 In Page 36，this code can't be complied: auto filtered = filter!((a) = Clock.currTime() - a.timeLastModified 14.days)(sorted); sorted's type is DirEntry[]. The errors : Error 1 Error: 'currTime(cast(immutable(TimeZone))opCall()).opBinary(a.timeLastModified())' is not of integral type, it is a Duration I don't know what's the problem?
Re: Clock.currTime
Kent: I am reading the book 《D Cookbook》 In Page 36，this code can't be complied: auto filtered = filter!((a) = Clock.currTime() - a.timeLastModified 14.days)(sorted); Perhaps: mySorted.filter!(a = Clock.currTime - a.timeLastModified 14.days); Bye, bearophile
Re: Clock.currTime
On Thursday, 20 November 2014 at 15:33:37 UTC, Kent wrote: mySorted.filter!(a = Clock.currTime - a.timeLastModified 14.days); Thank you for your reply. But it still doesn't work. Are you sure you saw the important difference? There was a in the first post and it should be . There's a few times throughout chapter one and two of the book where some symbols got messed up in the editing process and not fixed by the final draft. This looks like one of them.
Re: Clock.currTime
On Thursday, 20 November 2014 at 15:31:28 UTC, bearophile wrote: Kent: I am reading the book 《D Cookbook》 In Page 36，this code can't be complied: auto filtered = filter!((a) = Clock.currTime() - a.timeLastModified 14.days)(sorted); Perhaps: mySorted.filter!(a = Clock.currTime - a.timeLastModified 14.days); Bye, bearophile Thank you for your reply. But it still doesn't work.
Re: Clock.currTime
On Thursday, 20 November 2014 at 15:38:10 UTC, Adam D. Ruppe
wrote:
On Thursday, 20 November 2014 at 15:33:37 UTC, Kent wrote:
mySorted.filter!(a = Clock.currTime - a.timeLastModified
14.days);
Thank you for your reply.
But it still doesn't work.
Are you sure you saw the important difference? There was a
in the first post and it should be .
There's a few times throughout chapter one and two of the book
where some symbols got messed up in the editing process and not
fixed by the final draft. This looks like one of them.
I have notice the difference.Changed the to .
void main(string[] argv)
{
import std.file, std.algorithm, std.datetime,
std.range,std.stdio;
DirEntry[] allFiles;
foreach(DirEntry entry; dirEntries(E:/TDDOWNLOAD,
SpanMode.depth))
allFiles ~= entry;
auto sorted = sort!((a,b) = a.size b.size)(allFiles);
auto filtered = filter!(a = Clock.currTime() -
a.timeLastModified 14.days)(sorted);
foreach(file; filtered.take!(10))
writeln(fiel.name);
}
Re: Clock.currTime
On Thursday, 20 November 2014 at 15:45:55 UTC, Kent wrote: foreach(file; filtered.take!(10)) Oh, there shouldn't be a ! there either. Should be take(10), not take!(10). That's my mistake too... writeln(fiel.name); also file is misspelled.
Re: Clock.currTime
On Thursday, 20 November 2014 at 15:56:34 UTC, Adam D. Ruppe
wrote:
On Thursday, 20 November 2014 at 15:45:55 UTC, Kent wrote:
foreach(file; filtered.take!(10))
Oh, there shouldn't be a ! there either. Should be take(10),
not take!(10).
That's my mistake too...
writeln(fiel.name);
also file is misspelled.
Thank you very much for help me.
I notice another problem:
foreach(file; filtered.take!(10)){...}
This line has errors.I read the stdlib reference, and change the
line to:
foreach(file; take(filtered, 10)){...}
It becomes right.
Thank you again.
Re: help
On Thursday, 20 November 2014 at 07:25:45 UTC, Suliman wrote: You need to check if remote file exist of server and only after it download шею is this software name written in russian language?
Re: write multiple lines without \n with writeln
On 11/20/14, 9:05 AM, uri wrote: On Thursday, 20 November 2014 at 10:41:24 UTC, bearophile wrote: uri: It's by design And it's a nice handy design. Bye, bearophile For Wysiwyg strings I agree that it's great but I prefer C/C++/Python like behaviour for double quoted strings. I guess it's what I'm used to :) Cheers, uri In Crystal we chose the following: you can have two consecutive string literals but only if they are separated by a `\` at the end of the line. So this is a syntax error: foo(bar baz) But this is ok: foo(bar \ baz) Likewise, this is an error: [foo, bar baz, qux] # most probably we forgot to add a comma But this is ok: [foo, bar \ baz, qux] This way you avoid silly typing mistakes while at the same time you allow splitting a string across several lines without having to concatenate them at runtime.
Re: TKd handling of custom events
On Wednesday, 19 November 2014 at 23:44:00 UTC, univacc wrote: Hello, I am using TKd to dray my linux/windows app which works very good! I would like to add a global Hotkey to my program via the Win32 API function RegisterGlobalHotkey. Is there a possibility to access Tk's event loop so that you can Handle the WM_HOTKEY message, the WinAPI sends you? Regards, univacc I don't think this is possible in Tcl/Tk without installing an extension as discussed here: http://computer-programming-forum.com/57-tcl/c9af2b9def3914c2.htm Tkd doesn't rely on any extensions and is just using vanilla Tcl/Tk.
Re: Compiler error with slices, .dup and ref Parameter
On 11/20/2014 02:49 AM, bearophile wrote: in Bugzilla to see if there's already an ER Yep, existing ER: https://issues.dlang.org/show_bug.cgi?id=11529 Ali
Question about Vectors
So I was reading the documentation page:
http://dlang.org/simd.html and noticed what appears to be a typo:
int4 v;
(cast(int*)v)[3] = 2; // set 3rd element of the 4 int vector
(cast(int[4])v)[3] = 2; // set 3rd element of the 4 int vector
v.array[3] = 2; // set 3rd element of the 4 int vector
v.ptr[3] = 2;// set 3rd element of the 4 int vector
v.array[3] = 2; and v.ptr[3] = 2; set the fourth element, and not
the third.
As I was verifying this, I realized I had to compile it in 64 bit
code. The 32 bit code produced the error SIMD vector types not
supported on this platform.
My test code is:
void main() {
import std.stdio;
import core.simd;
int4 v = 7;
v.ptr[3] = 2;
writeln(v.array[]);
}
Is that related to me compiling while using a 64 bit OS, or is
that true of any 32 bit OS, and thus, vectors can't be used in
programs intended to be run on 32 bit OSs?
Thanks,
Charles
Re: help
On Thursday, 20 November 2014 at 16:48:29 UTC, MachineCode wrote: On Thursday, 20 November 2014 at 07:25:45 UTC, Suliman wrote: You need to check if remote file exist of server and only after it download шею is this software name written in russian language? шею means it. on russian keyboard layout
Re: print yyyy-mm-dd
On Thursday, 20 November 2014 at 13:50:49 UTC, Suliman wrote: I can't understand how to get date in format -MM-dd from Clock.currTime auto time = Clock.currTime; And what next? Could anybody give any examples? http://dpaste.dzfl.pl/73c0438f9d1e currTime returns SysTime; You can then cast is to Date. And Date has toISOExtString which converts Date to a string with the format -MM-DD.
Re: Dub / Derelict confusion
On Wednesday, 19 November 2014 at 10:07:56 UTC, Mike Parker wrote:
On 11/19/2014 6:12 PM, Paul wrote:
I would like to create a simple program using SDL. I've read
this page
http://dblog.aldacron.net/derelict-help/using-derelict/ and
this one
http://code.dlang.org/about and decided that using 'dub' would
be the
sensible option for a beginner so I downloaded the dub
executable and
put it in the same directory as my source file 'test.d'.
It doesn't need to be in the same directory as the source. Put
it somewhere on the global path.
As per the example at the above url, I created a dub.json file
in the
same directory with contents as so:
dependencies: {
derelict-sdl2:~1.0.0,
derelict-gl3:~master,
}
You shouldn't be depending on ~master for anything anymore. The
newest version of dub will complain about dependencies on git
branches. For derelict-gl3, you can use =1.0.0.
If I have the relevant import statements in test.d, am I right
in
thinking I can use dub to build my program (not just download
and build
the derelict libraries)?
Yes, assuming that your dub.json is properly configured.
The command dub build test.d gives me a 'failed
to load package' error.
That's the right command, but the wrong parameters. If you are
going to pass a parameter to the build command, it should be
the name of a dub package, not the name of a file. Typically,
you don't need to pass it a package name if all is properly
configured.
Try this:
1 -- make sure dub is on the global path.
2 --
mkdir dubtest
cd dubtest
dub init
You should see the following output in side the dubtest dir
-dub.json
---source
-app.d
3 --
Edit dub.json and add the following dependencies:
derelict-sdl2:~1.0.0,
derelict-gl3:=1.0.0
4 --
Edit app.d to look like this:
import derelict.opengl3.gl3,
derelict.sdl2.sdl;
void main()
{
DerelictGL3.load();
DerelictSDL2.load();
import std.stdio : writeln;
writeln( Success!);
}
5--
Execute the following command:
dub
You'll see some messages about fetching and building the
Derelict packages and then, assuming you have SDL2 and OpenGL
on your system library search path, you should see it print
Success!. Otherwise, you'll get a DerelictException of one
kind or another.
Note that I didn't give dub a command option. Executing 'dub'
with no options will cause it to build and run whatever package
is in the current directory. By default, dub will look for
source/app.d if you don't configure something differently in
dub.json.
Executing 'dub build' will build the executable, but will not
run it.
This is a tad off topic now but I'm struggling to get a window on
screen as SDL_CreateWindow is failing, here's what I've got:
try{
DerelictSDL2.load();
}catch(Exception e){
writeln(Failed to load DerelictSDL2 :( %s, e.msg);
return;
}
try{
SDL_Init(SDL_INIT_EVERYTHING);
}catch(Exception e){
writeln(Can't init SDL :( %s, e.msg);
return;
}
SDL_Window *testWindow;
//temporary magic numbers ahoy
testWindow = SDL_CreateWindow( Test Window,
SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600,
SDL_WINDOW_RESIZABLE );
if( testWindow == null ) {
writeln(Window could not be created!);
return;
} else {
SDL_Surface* testSurface;
testSurface = SDL_GetWindowSurface(testWindow);
}
Everything seems to initialise ok but SDL_CreateWindow always
returns null. For some reason I can't use DerelictException which
I guess might help me dig deeper. AFAIK there are no issues with
this machine's hardware - I can certainly run other SDL-based
apps on it.
Operator Overloading in an Abstract Base Class
In my module symbolic.d at https://github.com/nordlow/justd/blob/master/symbolic.d is it somehow possible to overload binary operator ~ on pairs of instances SPatt? I'm asking because my current try at https://github.com/nordlow/justd/blob/master/symbolic.d#L332 is not called in the unittest at https://github.com/nordlow/justd/blob/master/symbolic.d#L347 Isn't it possible to do operator overloading in an abstract base-class?
Re: Operator Overloading in an Abstract Base Class
On Thursday, 20 November 2014 at 22:10:28 UTC, Nordlöw wrote: In my module symbolic.d at https://github.com/nordlow/justd/blob/master/symbolic.d is it somehow possible to overload binary operator ~ on pairs of instances SPatt? As usual I had done a couple of mistakes...which are solved know at https://github.com/nordlow/justd/blob/master/symbolic.d#L63 Why can't I find these bugs before I do my posts? :)
Re: print yyyy-mm-dd
On Thursday, 20 November 2014 at 20:38:08 UTC, MrSmith wrote: On Thursday, 20 November 2014 at 13:50:49 UTC, Suliman wrote: I can't understand how to get date in format -MM-dd from Clock.currTime auto time = Clock.currTime; And what next? Could anybody give any examples? http://dpaste.dzfl.pl/73c0438f9d1e currTime returns SysTime; You can then cast is to Date. And Date has toISOExtString which converts Date to a string with the format -MM-DD. There's no need to cast, SysTime supports conversion to string http://dlang.org/library/std/datetime/SysTime.toISOExtString.html http://dlang.org/library/std/datetime/SysTime.toISOString.html If you want just the -MM-DD slice it Clock.currTime.toISOExtString[0..10].writeln; Clock.currTime.toISOString[0..8].writeln; Cheers, uri
Re: Operator Overloading in an Abstract Base Class
On 11/20/2014 02:18 PM, Nordlöw wrote:
On Thursday, 20 November 2014 at 22:10:28 UTC, Nordlöw wrote:
In my module symbolic.d at
https://github.com/nordlow/justd/blob/master/symbolic.d
is it somehow possible to overload binary operator ~ on pairs of
instances SPatt?
As usual I had done a couple of mistakes...which are solved know at
https://github.com/nordlow/justd/blob/master/symbolic.d#L63
Why can't I find these bugs before I do my posts? :)
Glad that it works. :)
Not directly related to your post but just because your post reminded
me, there is the following feature that simplifies matters when one
needs virtual operators:
template opOpAssign(string op) if (op == ~)
{ alias concatAssign opOpAssign; }
Here is the enhancement request:
https://issues.dlang.org/show_bug.cgi?id=5893
And here is the implementation including the tests:
https://github.com/D-Programming-Language/dmd/pull/989/files#diff-51d0a1ca6214e6a916212fcbf93d7e40R246
Ali
Re: Operator Overloading in an Abstract Base Class
On Thursday, 20 November 2014 at 22:10:28 UTC, Nordlöw wrote:
In my module symbolic.d at
https://github.com/nordlow/justd/blob/master/symbolic.d
is it somehow possible to overload binary operator ~ on pairs
of instances SPatt?
I'm asking because my current try at
https://github.com/nordlow/justd/blob/master/symbolic.d#L332
is not called in the unittest at
https://github.com/nordlow/justd/blob/master/symbolic.d#L347
Isn't it possible to do operator overloading in an abstract
base-class?
Seq opBinary(string op)(Patt rhs)
{
static if (op == ~)
{
return seq(this, rhs);
}
else
{
static assert(false, Unsupported binary operator ~ op);
}
}
As far I understood your question, you want to override opBinary
in a derived class?
You can't do it directly, because opBinary is template and
template can not be overriten. However, you may declare virtual
non-template method for ~ and call it from opBinary.
And `static if (op == ~)` is not good. Use template constraint
instead:
class Patt
{
// It is better then your static if.
// Compiler will raise better error message for incorrect
operator.
Seq opBinary(string op)(Patt rhs) if (op == ~)
{
return opCatImpl(rhs);
}
protected Seq opCatImpl(Patt rhs) //you may override it in
derived class
{
return seq(this, rhs);
}
}
Re: Dub / Derelict confusion
On 11/21/2014 5:57 AM, Paul wrote:
This is a tad off topic now but I'm struggling to get a window on screen
as SDL_CreateWindow is failing, here's what I've got:
try{
DerelictSDL2.load();
}catch(Exception e){
writeln(Failed to load DerelictSDL2 :( %s, e.msg);
return;
}
Before getting to your issue, I'd like to point out that this is a
needless redundancy. You are adding anything by catching an exception
here and printing to the console that the library didn't load. The
exception message will tell you that already. I suggest you just remove
the try..catch and let the exception propagate. The only reason to catch
a DerelictException here is if you want to do something other than print
the message to the console, like display a message box or write to a log
file.
try{
SDL_Init(SDL_INIT_EVERYTHING);
}catch(Exception e){
writeln(Can't init SDL :( %s, e.msg);
return;
}
SDL_Init isn't goint to throw an exception. It can't. It's a function in
a C library and C doesn't know anything about D exceptions. If you look
at the documentation for SDL_Init[1], you will find that it returns a
negative number on failure and 0 on success.
if( SDL_Init( SDL_INIT_EVERYTHING ) 0 ) {
// See below for how to handle this
}
SDL_Window *testWindow;
//temporary magic numbers ahoy
testWindow = SDL_CreateWindow( Test Window, SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_RESIZABLE );
if( testWindow == null ) {
writeln(Window could not be created!);
return;
} else {
SDL_Surface* testSurface;
testSurface = SDL_GetWindowSurface(testWindow);
}
Everything seems to initialise ok but SDL_CreateWindow always returns
null. For some reason I can't use DerelictException which I guess might
help me dig deeper. AFAIK there are no issues with this machine's
hardware - I can certainly run other SDL-based apps on it.
Again, DerelictExceptions aren't going to help you here. They are only
thrown when the load function fails (to manipulate a DerelictException
directly, import derelict.util.exception.) To get an error message out
of SDL, you need to call SDL_GetError, which returns a const( char )*.
void printSDLError( string msg ) {
import std.conv : to;
import std.stdio : writefln;
writefln(%s: %s, msg, to!string( SDL_GetError() ));
}
...
if( testWindow == null )
{
printSDLError( Failed to create window. );
return;
}
I prefer to wrap it up in a subclass of Error. Others may prefer
Exception, but when I throw an SDLError I don't intend to catch it. I
really want the app to exit.
class SDLError : Error
{
public static string errStr() @property
{
import std.conv : to;
import derelict.sdl2.sdl : SDL_GetError;
return to!string( SDL_GetError() );
}
public this( string msg, string file = __FILE__, size_t line =
__LINE__ )
{
import std.string : format;
auto fmsg = format( %s: %s, msg, errStr );
super( fmsg, file, line );
}
}
Now it becomes:
DerelictSDL2.load();
if( SDL_Init( SDL_INIT_EVERYTHING ) 0 )
{
throw new SDLError( Failed to initialize SDL );
}
testWindow = SDL_CreateWindow( ... );
if( !testWindow )
{
throw new SDLError( Failed to create window );
}
Whichever approach you choose, SDL_GetError will shed light on why any
SDL call failed as long as you call it immediately upon failure.
[1]
https://wiki.libsdl.org/SDL_Init?highlight=%28%5CbCategoryInit%5Cb%29%7C%28CategoryEnum%29%7C%28CategoryStruct%29
Re: Dub / Derelict confusion
On 11/21/2014 10:22 AM, Mike Parker wrote: You are adding anything You /aren't/
