Re: Using replaceInPlace, string and char[]
Must create a ticket for it ? I think so. Unless others object in 10 minutes... :) :-) Done : https://issues.dlang.org/show_bug.cgi?id=14925 Thanks for your help
Using replaceInPlace, string and char[]
Hi,
A newbie question :
I wrote this simple code :
import std.array;
import std.stdio;
void main()
{
char[] a = mon texte 1.dup;
char[] b = abc.dup;
size_t x = 4;
size_t y = 9;
replaceInPlace( a, x , y, b );
writeln( a );
}
But compilation fails :
/usr/include/dmd/phobos/std/array.d(2052): Error: template
std.algorithm.remove cannot deduce function from argument types
!()(char[], Tuple!(immutable(uint), uint)), candidates are:
/usr/include/dmd/phobos/std/algorithm.d(8542):
std.algorithm.remove(SwapStrategy s = SwapStrategy.stable, Range,
Offset...)(Range range, Offset offset) if (s !=
SwapStrategy.stable isBidirectionalRange!Range
hasLvalueElements!Range hasLength!Range Offset.length = 1)
/usr/include/dmd/phobos/std/algorithm.d(8623):
std.algorithm.remove(SwapStrategy s = SwapStrategy.stable, Range,
Offset...)(Range range, Offset offset) if (s ==
SwapStrategy.stable isBidirectionalRange!Range
hasLvalueElements!Range Offset.length = 1)
/usr/include/dmd/phobos/std/algorithm.d(8757):
std.algorithm.remove(alias pred, SwapStrategy s =
SwapStrategy.stable, Range)(Range range) if
(isBidirectionalRange!Range hasLvalueElements!Range)
inout.d(13): Error: template instance
std.array.replaceInPlace!(char, char[]) error instantiating
Don't understand why this doesn't work: it compiles fine and runs
perfectly if I change char[] by string ... don't understand
why since the documentation says :
String literals are immutable (read only).
How this function can change a type that is immutable ?
Thanks for your help.
TSalm
Re: Using replaceInPlace, string and char[]
On Saturday, 15 August 2015 at 08:07:43 UTC, Ali Çehreli wrote:
This looks like a bug to me. The template constraints of the
two overloads are pretty complicated. This case should match
only one of them.
Yes I understand. I've used ldc2. With DMD (v0.067.1) the error
is more clear :
inout.d(11): Error: std.array.replaceInPlace called with argument
types (char[], uint, uint, char[]) matches both:
/usr/include/dmd/phobos/std/array.d(2214):
std.array.replaceInPlace!(char, char[]).replaceInPlace(ref char[]
array, uint from, uint to, char[] stuff)
and:
/usr/include/dmd/phobos/std/array.d(2247):
std.array.replaceInPlace!(char, char[]).replaceInPlace(ref char[]
array, uint from, uint to, char[] stuff)
Must create a ticket for it ?
Don't understand why this doesn't work: it compiles fine and
runs
perfectly if I change char[] by string
You mean, this:
import std.array;
import std.stdio;
void main()
{
string a = mon texte 1;// -- now string
writeln(a.ptr); // added
char[] b = abc.dup;
size_t x = 4;
size_t y = 9;
replaceInPlace( a, x , y, b );
writeln( a );
writeln(a.ptr); // added
}
The output:
4BC480
mon abc 1
7FC2AB867210-- different
... don't understand why
since the documentation says :
String literals are immutable (read only).
How this function can change a type that is immutable ?
It cannot change the characters of the original string.
replaceInPlace takes its first parameter by reference. What
changes is 'a' itself. As evidenced by the output of the
program, 'a' is now a slice to a new set of immutable
characters.
If there were other slices to mon texte 1, they wouldn't see
a change.
Yes I understand, thanks. In the other hand using string is not
efficient since this certainly make a copy of the original
string. Right ?
This is better to use replaceInPlace with char[], but this
doesn't actually work :-(
Searching for a tool to use D for web development with Apache
Hello, Does it exist a project to use D in web development with Apache; not for CGI scripts, but rather like what PHP does ? Thanks in advance for your help. I hope this is the correct forum to post my question on. Sorry if not. Regards. -TSalm
C equivalent for the D float type
Hello, What is the C equivalent for the D float type ? Thanks in advance, TSalm
Re: C equivalent for the D float type
What is the C equivalent for the D float type ? float and double is double. in c, real support is compiler dependant, it may or may not be available. Thanks !
Re: const argument
Le Sat, 28 Mar 2009 12:21:52 +0100, Jarrett Billingsley
jarrett.billings...@gmail.com a écrit:
On Sat, Mar 28, 2009 at 6:12 AM, TSalm ts...@free.fr wrote:
Hello,
Is there a way to specifie a constant argument ( I would say an
argument for
which his value is evaluate at compile time )
For example, something like this :
/* CODE - */
import tango.io.Stdout;
void func(const bool constArg)
{
static if (constArg)
Stdout(Yes).newline;
else
Stdout(No).newline;
}
void main()
{
func( true );
func( false );
}
/* END CODE - */
You have to do it with templates:
void func(bool constArg)()
{
static if(constArg) ... else ...
}
func!(true)();
func!(false)();
Thanks.
Walter suggested, in the D2 presentation at the conference in 2007,
that there should be static parameters which would work the way your
code should work.
good idea IMO.
Re: Generic functions to convert to void* and from void*
Le Wed, 25 Feb 2009 01:03:32 +0100, Daniel Keep daniel.keep.li...@gmail.com a écrit: TSalm wrote: In my case, there's also no possibility to get the wrong type, because it is managed by the type of the ColumnMem. You still have to get the code right. There's a surprising number of corner cases trying to store arbitrary types. And about Object, if I want to store base type like int,double,etc..., if I do something like : Object o; int a = 30 ; o = cast(Object) a ; is this syntax is GC safe ? It's not safe, period. If the compiler lets you do that, I'd be tremendously surprised; even more surprised if it doesn't cause major problems later. This is what I'm worried about; you're doing dangerous things with a type system you don't understand. Don't do this. Here's the problem: void* isn't going to work for everything. It'll work for Object references, other pointers, and that's it. You can't store arrays, and you can't store value types like structs or primitive types. For that, you need to allocate heap storage, copy the value and then store the pointer to that. Oh, and don't forget that fixed-length arrays have value semantics whereas dynamic arrays and slices have reference semantics; although you generally solve that issue by having a special template for your type which rewrites T[n] as T[]. Also, delegates won't fit, but function pointers will. This is why I was pointing you at Variant because I already went through the trouble to solve all this once. :P If you still want to do this with void*, build that code in isolation and test the heck out of it. You are right. I will first use Variant to implements all functionnalities, and insolating the storage type. And in the future, I will be able to use void* as an improvement.
Re: Generic functions to convert to void* and from void*
TSalm wrote: I'm trying to build function which have the hability to convert a type to void* and from void*. First of all, I have to ask: have you looked at std.variant / tango.core.Variant? Yes, but it seems that Variant class uses more memory than void* . The Phobos Variant will use however much space you reserve as the maximum, plus 4 bytes for a function pointer, but it can only store types as big as you allow for. The Tango version will use max(real.sizeof,void[].sizeof) + 4 bytes for the typeid and can store anything you throw at it. For that extra space, both of these will give you runtime type safety, meaning you can't accidentally get the types wrong. They're MUCH safer than void*. In my case, there's also no possibility to get the wrong type, because it is managed by the type of the ColumnMem. [...] I get the distinct impression that you're seriously over-thinking this. Both of these functions could be rewritten as casts. Aside from that, you've given no context for me to have any idea what you're trying to accomplish here. I'm really a newbie concerning the use of void* ( I think you have notice this ;-) ) Thanks for your usefull remarks. void* is just a pointer like any other. It doesn't have any special properties except that you cannot dereference it; that's it. If you're not sure how to use pointers, then don't. For example, you could store objects instead; this takes the same amount of storage in the DBMS, and allows for safe casting back to the original type. Plus, you don't have to stuff about with casting things to void* and back. I'm simply trying to make a little and lightweight DBMS in memory. Simply made by classes like TableMem, RowMem and ColumnMem(T). There's also a private class which aims to store datas, using void*[][]. Unless you really need to store small value types like integers, etc. in that private data, objects might be the best bet for now. Thanks. And about Object, if I want to store base type like int,double,etc..., if I do something like : Object o; int a = 30 ; o = cast(Object) a ; is this syntax is GC safe ?
Re: Generic functions to convert to void* and from void*
I'm trying to build function which have the hability to convert a type to void* and from void*. First of all, I have to ask: have you looked at std.variant / tango.core.Variant? Yes, but it seems that Variant class uses more memory than void* . [...] I get the distinct impression that you're seriously over-thinking this. Both of these functions could be rewritten as casts. Aside from that, you've given no context for me to have any idea what you're trying to accomplish here. I'm really a newbie concerning the use of void* ( I think you have notice this ;-) ) Thanks for your usefull remarks. I'm simply trying to make a little and lightweight DBMS in memory. Simply made by classes like TableMem, RowMem and ColumnMem(T). There's also a private class which aims to store datas, using void*[][].
Generic functions to convert to void* and from void*
Hello,
I'm trying to build function which have the hability to convert a type to
void* and from void*.
I must use ref in the toPtr function because of this :
http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.comgroup=digitalmars.D.learnartnum=15600
Do you think that what I done is correct ?
/* - CODE - */
/***
* Convert a value to a void*
* Params:
* val =
* Returns:
*/
void* toPtr(T)(ref T val)
{
void* p ;
static if ( is( T b : Type ) )
{
p = new T ;
p = val ;
}
else
{
p = val ;
}
return p ;
}
/***
* Convert a void* to his value
* Params:
* ptr =
* Returns:
*/
T fromPtr(T)(void* ptr)
{
return *(cast(T*)ptr) ;
}
/* --- END CODE */
Thanks in advance,
TSalm
Re: Generic functions to convert to void* and from void*
I'm trying to build function which have the hability to convert a type
to void* and from void*.
I must use ref in the toPtr function because of this :
http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.comgroup=digitalmars.D.learnartnum=15600
Do you think that what I done is correct ?
/* - CODE - */
/***
* Convert a value to a void*
* Params:
* val =
* Returns:
*/
void* toPtr(T)(ref T val)
{
void* p ;
static if ( is( T b : Type ) )
{
p = new T ;
p = val ;
}
else
{
p = val ;
}
return p ;
}
/***
* Convert a void* to his value
* Params:
* ptr =
* Returns:
*/
T fromPtr(T)(void* ptr)
{
return *(cast(T*)ptr) ;
}
/* --- END CODE */
I've forget to say that toPtr can't be call with constants.
Re: Symbol undefined on interface with public getter and package setter
Le Sat, 21 Feb 2009 04:00:42 +0100, Daniel Keep daniel.keep.li...@gmail.com a écrit: TSalm wrote: I'm not sure but I think package is not virtual. :-( So there's really no way to have a method declared package in an interface ? You also can't have a private function in an interface. This once lost me four days trying to figure out why my program wouldn't link despite the function very obviously being there. Stick to public functions only. What a pity :( Thanks.
Symbol undefined on interface with public getter and package setter
Hello,
When I compile the code below, I've got the following error :
OPTLINK (R) for Win32 Release 8.00.1
Copyright (C) Digital Mars 1989-2004 All rights reserved.
private_method_in_interface_file3.obj(private_method_in_interface_file3)
Error 42: Symbol Undefined
_D33private_method_in_interface_file31I4funcMFiZv
--- errorlevel 1
/* - CODE -- */
interface I
{
int func() ;
package void func(int);
}
class A:I
{
int i;
package void func(int i)
{ this.i = i; }
int func()
{ return i; }
}
void main()
{
I a = new A ;
a.func = 10 ;
Stdout(a.func).newline ;
}
/* --- END CODE */
Thanks in advance for your help,
TSalm
Re: Symbol undefined on interface with public getter and package setter
It seems this comes only from the package method.
The error is the same with this code :
/* --- CODE --- */
interface I
{
package void setFunc(int);
}
class A:I
{
int i;
package void setFunc(int i)
{ this.i = i ; }
}
void main()
{
I a = new A;
a.setFunc = 10;
}
/* --- END CODE --- */
Hello,
When I compile the code below, I've got the following error :
OPTLINK (R) for Win32 Release 8.00.1
Copyright (C) Digital Mars 1989-2004 All rights reserved.
private_method_in_interface_file3.obj(private_method_in_interface_file3)
Error 42: Symbol Undefined
_D33private_method_in_interface_file31I4funcMFiZv
--- errorlevel 1
/* - CODE -- */
interface I
{
int func() ;
package void func(int);
}
class A:I
{
int i;
package void func(int i)
{ this.i = i; }
int func()
{ return i; }
}
void main()
{
I a = new A ;
a.func = 10 ;
Stdout(a.func).newline ;
}
/* --- END CODE */
Thanks in advance for your help,
TSalm
Re: Symbol undefined on interface with public getter and package setter
I'm not sure but I think package is not virtual. :-( So there's really no way to have a method declared package in an interface ?
Re: Template function : use the array's one !
TSalm Wrote: int compare(T:T[])(T[] o1,T[] o2) Change this line to: int compare(T:T[])(T o1, T o2) You are right. But despite this function, at compile time, an error is return : .\src\tsalm\tools\Generic.d(20): Error: cannot implicitly convert expression (o2 - o1) of type int[3u] to int .\src\tsalm\tools\Generic.d(33): template instance tsalm.tools.generic.compare!(int[3u]) error instantiating Command C:\DMD\dsss\bin\rebuild.exe returned with code 1, aborting. Error: Command failed, aborting.
Re: Template function : use the array's one !
take a look at static if and is http://www.digitalmars.com/d/1.0/version.html#staticif http://www.digitalmars.com/d/1.0/expression.html#IsExpression Thanks for this links. But I don't see anything about how to test if it's an array or not... Is it not possible ?
Re: Template function : use the array's one !
Le Tue, 17 Feb 2009 23:03:04 +0100, BCS n...@anon.com a écrit:
Hello TSalm,
take a look at static if and is
http://www.digitalmars.com/d/1.0/version.html#staticif
http://www.digitalmars.com/d/1.0/expression.html#IsExpression
Thanks for this links.
But I don't see anything about how to test if it's an array or not...
Is it not possible ?
look at point 5
IIRC:
static if(is(T B : B[]))
{
// if T is an array, this is used and B is the element type
}
Incredible !
Thanks a lot BCS.
Re: return *(cast(T*)vPtr) and OutOfMemoryException
Excellent explication !
Thank you Frits
Le Sat, 14 Feb 2009 17:58:35 +0100, Frits van Bommel
fvbom...@remwovexcapss.nl a écrit:
TSalm wrote:
Hello,
In the code below, why the first Stdout throws a Exception when the
second doesn't ?
/* CODE */
import tango.io.Stdout;
struct VoidPtr(T)
{
void* vPtr;
void value(T val)
{
vPtr = val;
Here you're storing a pointer to a non-ref parameter. This is the bug;
the parameter itself is implicitly deallocated on returning from this
function.
Change to 'ref T val' to fix it.
Essentially, an array is a struct { size_t length; T ptr; }. This means
'val' refers to a copy in the stack frame of this function, not to 'arr'
in main().
}
T value()
{
return *(cast(T*)vPtr);
}
}
void main()
{
VoidPtr!(char[][]) vPtr ;
char[][] arr = [ hello , you ];
vPtr.value = arr ;
Stdout( vPtr.value ).newline; // --
[tango.core.Exception.OutOfMemoryException: Memory allocation failed
Here you're calling a new function, overwriting *vPtr with something
else (probably vptr itself), resulting in a huge array when you try to
read it later.
Stdout( *(cast(char[][]*) vPtr.vPtr ) ); // -- This works good
This reads the (implicitly deallocated) 'val' parameter before it gets
overwritten, hiding the bug. It's still there: just because the code
doesn't crash doesn't mean it's correct.
}
/* -- END CODE -- */
Thanks in advance for your help,
TSalm
Re: Internal delegate and Stack Overflow
Le Sat, 29 Nov 2008 01:49:20 +0100, BCS [EMAIL PROTECTED] a écrit:
struct C(R, A...)
{
A args;
R function(A) dg;
static R delegate() opCall(R function(A) dg, A a)
{
C!(R, A) ret;
ret.dg=dg;
foreach(int i,_;A)
ret.args[i] = a[i];
return ret.fn;
}
R fn() { return dg(args); }
}
// test it
import std.stdio;
int delegate() dg(int i)
{
return C!(int,int)(function int(int j){return j;}, i); // --- used
here
}
void main()
{
auto d = dg(5);
writef(%s\n, d());
}
Interesting code. Thanks!
Re: Internal delegate and Stack Overflow
Le Sat, 29 Nov 2008 01:08:28 +0100, BCS [EMAIL PROTECTED] a écrit:
Reply to TSalm,
Hello,
I would do something like this, but this return me an execution error
: object.Exception: Stack Overflow
// CODE
class A
{
void delegate() dg;
void doIt()
{
dg();
}
}
class B
{
A a;
this()
{
a = new A;
a.dg = { doSomething(); };
}
void doSomething() { }
}
void main()
{
auto b = new B;
b.a.doIt();
}
// --END CODE--
Is this a bug or have I do something wrong ?
Thanks in advance for your help,
TSalm
If this is d1.0 the error is that you are allowing an anon delegate to
escape the enclosing function.
Yes, it's on D1.036.
a.dg = this.doSomething; // this would be ok if that helps.
if it is 2.0, I think this is correct.
Yes, you are right.
But this is an example code. The true code uses delegates with argument
which differs from called functions, so I can't point delegate directly to
them.
And this anonymous function's way is really fastest to code... I must
waiting for a D2 stable version ;-)
Thanks
Compilation error when using a extern function ?
Hello,
I'm on DMD 1.036.
When I'm compiling this code :
// -CODE---
enum ColorValues:uint
{
AliceBlue = 0xF0F8
,AntiqueWhite = 0xF8ECD8FF
,Aqua = 0x00FF
,Aquamarine = 0x80FFD0FF
,Azure = 0xF0FF
,Beige = 0xF8F4E0FF
,Bisque = 0xFFE4C8FF
[...]
Color convertToColor(uint val)
{
ubyte[4] colorVal = *cast(ubyte*)val;
return Color(colorVal[0]
,colorVal[1]
,colorVal[2]
,colorVal[3]
);
}
class DFLCalendar:Panel
{
// Graphicals objects
protected
{
// Colors default preferences :
const Color colorPanMonth =
convertToColor(cast(uint)ColorValues.MidnightBlue);
const Color colorPanDays =
convertToColor(cast(uint)ColorValues.White);
const uint heightPanMonth = 16 ;
const uint widthButChangeMonth = 10;
[...]
// -END CODE---
The compiler return me the error :
tools\gui\tools\DFLCalendar.d(29): Error: cannot evaluate
convertToColor(404254975u) at compile time
Line 29 corresponds to const Color colorPanMonth =
convertToColor(cast(uint)ColorValues.MidnightBlue);
Thanks in advance for your help,
TSalm
