Re: ImportC std support
On Sunday, 12 December 2021 at 07:40:10 UTC, ManKey wrote: On Saturday, 11 December 2021 at 22:28:16 UTC, forkit wrote: On Saturday, 11 December 2021 at 21:42:49 UTC, ManKey wrote: umm... the site has search function you know ;-) Dude, you see, it doesn't say anything about it. It says a little about the extension, but there is no direct answer. This is important because C Std is very dependent on the compiler and its extensions, for example msvc std c does not work with importC. So my question is, are there any implementations of the standard C library that importC supports? ImportC is not ready for general use yet. I’ve been reporting bugs that crop up when trying to use standard c headers, but I mostly use Linux and Macs so I haven’t reported any constructs it doesn’t understand on Windows. It’s supposed to be able to compile standard C11 code. If you run into one, report it at https://issues.dlang.org and use the ImportC keyword!
Re: How to loop through characters of a string in D language?
On Saturday, 11 December 2021 at 19:50:55 UTC, russhy wrote:
you need to import a 8k lines of code module that itself
imports other modules, and then the code is hard to read
I agree.
```
@safe:
auto deatheater(char stripchar)(string str) {
struct voldemort {
immutable(char)* begin, end;
bool empty(){ return begin == end; }
char front(){ return *begin; }
char back()@trusted{ return *(end-1); }
void popFront()@trusted{
while(begin != end){begin++; if (*begin != stripchar)
break; }
}
void popBack()@trusted{
while(begin != end){end--; if (*(end-1) != stripchar)
break; }
}
this(string s)@trusted{
begin = s.ptr;
end = s.ptr + s.length;
}
}
return voldemort(str);
}
void main() {
import std.stdio;
string str = "abc;def;ab";
foreach(c; deatheater!';'(str)) write(c);
writeln();
foreach_reverse(c; deatheater!';'(str)) write(c);
}
```
Re: How to loop through characters of a string in D language?
On Sunday, 12 December 2021 at 08:58:29 UTC, Ola Fosheim Grøstad
wrote:
this(string s)@trusted{
begin = s.ptr;
end = s.ptr + s.length;
}
}
Bug, it fails if the string ends or starts with ';'.
Fix:
```
this(string s)@trusted{
begin = s.ptr;
end = s.ptr + s.length;
while(begin!=end && *begin==stripchar) begin++;
while(begin!=end && *(end-1)==stripchar) end--;
}
```
Re: How to loop through characters of a string in D language?
Of course, since it is easy to mess up and use ranges in the
wrong way, you might want to add ```assert```s. That is most
likely *helpful* to newbies that might want to use your kickass
library function:
```
auto helpfuldeatheater(char stripchar)(string str) {
struct voldemort {
immutable(char)* begin, end;
bool empty(){ return begin == end; }
char front(){ assert(!empty); return *begin; }
char back()@trusted{ assert(!empty); return *(end-1); }
void popFront()@trusted{
assert(!empty);
while(begin != end){begin++; if (*begin != stripchar)
break; }
}
void popBack()@trusted{
assert(!empty);
while(begin != end){end--; if (*(end-1) != stripchar)
break; }
}
this(string s)@trusted{
begin = s.ptr;
end = s.ptr + s.length;
while(begin!=end && *begin==stripchar) begin++;
while(begin!=end && *(end-1)==stripchar) end--;
}
}
return voldemort(str);
}
```
template ctor overload Segmentation fault
Hello, why does this code fail to compile?
```d
struct Foo(T){
this(Rhs, this This)(scope Rhs rhs){
}
this(ref scope typeof(this) rhs){
}
}
struct Bar{
Foo!int foo;
}
void main(){
}
```
error: Segmentation fault (core dumped)
Restrict type of function parameter to a defined list of types?
Hi everyone,
lets say that required is a setter method:
```
Nullable!string str(Nullable!string setter) {
return this._str = setter;
}
```
The user should be able to:
```
auto a = new A();
a.str = "abc";
```
As the setters parameter is defined to be of type
`Nullable!string`, the compiler complains. So the user need to
do `a.str = nullable("abc");`
I guess a solution could be to define the setter as:
```
Nullable!string str(T)(T setter) {
return this._str = setter;
}
```
^stupid question: Is this the correct way to restrict the
parameter type to be `string` or `Nullable!string` or is there a
more precise way to restrict?
BTW: here is a more complete simple example of what i am talking
about: https://run.dlang.io/is/zP4vkb
Re: Restrict type of function parameter to a defined list of types?
On Sunday, 12 December 2021 at 13:11:58 UTC, Martin B wrote:
Hi everyone,
lets say that required is a setter method:
```
Nullable!string str(Nullable!string setter) {
return this._str = setter;
}
```
Just add a forwarding overload:
auto str(string s) { return this.str(nullable(s)); }
Then the user can pass either Nullable or string but not other
things.
Re: Restrict type of function parameter to a defined list of types?
On Sunday, 12 December 2021 at 13:21:06 UTC, Adam D Ruppe wrote:
On Sunday, 12 December 2021 at 13:11:58 UTC, Martin B wrote:
Just add a forwarding overload:
Hi Adam,
i am wondering if there is another possibility without having to
create overloads for each parameter type - something like this
pseudocode:
```
Nullable!string str(T : {string, Nullable!string}) (T setter) {
return this._str = setter;
}
```
Re: Restrict type of function parameter to a defined list of types?
On Sunday, 12 December 2021 at 13:42:08 UTC, Martin B wrote:
On Sunday, 12 December 2021 at 13:21:06 UTC, Adam D Ruppe wrote:
On Sunday, 12 December 2021 at 13:11:58 UTC, Martin B wrote:
Just add a forwarding overload:
Hi Adam,
i am wondering if there is another possibility without having
to create overloads for each parameter type - something like
this pseudocode:
```
Nullable!string str(T : {string, Nullable!string}) (T setter) {
return this._str = setter;
}
```
You can use a [template constraint][1]:
```d
Nullable!string str(T)(T setter)
if (is(T == string) || is(T == Nullable!string))
{
return this._str = setter;
}
```
[1]: https://dlang.org/spec/template.html#template_constraints
Re: unit test broken [DUB bug?]
You are running the beta version of the compiler, and an older version of LDC2 I'd first try to update them to make sure you aren't missing any bug fixes
Re: Restrict type of function parameter to a defined list of types?
On Sunday, 12 December 2021 at 14:11:48 UTC, Paul Backus wrote: You can use a [template constraint][1]: Hi Paul, yes! thats it, Thanks. I am facepalming me right now because have been on that webpage and missed that point.
Re: template ctor overload Segmentation fault
On Sunday, 12 December 2021 at 11:57:43 UTC, vit wrote:
Hello, why does this code fail to compile?
```d
struct Foo(T){
this(Rhs, this This)(scope Rhs rhs){
}
this(ref scope typeof(this) rhs){
}
}
struct Bar{
Foo!int foo;
}
void main(){
}
```
error: Segmentation fault (core dumped)
What are you trying to accomplish?
Re: Restrict type of function parameter to a defined list of types?
On Sunday, 12 December 2021 at 14:26:54 UTC, Martin B wrote: On Sunday, 12 December 2021 at 14:11:48 UTC, Paul Backus wrote: You can use a [template constraint][1]: Hi Paul, yes! thats it, Thanks. I am facepalming me right now because have been on that webpage and missed that point. Happens to everyone at some time 🌅
Re: template ctor overload Segmentation fault
On Sunday, 12 December 2021 at 18:32:28 UTC, Imperatorn wrote:
On Sunday, 12 December 2021 at 11:57:43 UTC, vit wrote:
Hello, why does this code fail to compile?
```d
struct Foo(T){
this(Rhs, this This)(scope Rhs rhs){
}
this(ref scope typeof(this) rhs){
}
}
struct Bar{
Foo!int foo;
}
void main(){
}
```
error: Segmentation fault (core dumped)
What are you trying to accomplish?
Something like this:
```d
import std.traits : CopyConstness;
struct UniquePtr(T){
alias Type = T;
this(Rhs, this This)(scope Rhs rhs)
if(is(CopyConstness!(Rhs, Rhs.Type*) : CopyConstness!(This,
This.Type*))){
//...
}
//one of copy ctors:
this(ref scope typeof(this) rhs){
//...
}
static UniquePtr make(Args...)(Args args){
return UniquePtr.init;
}
}
void main(){
const UniquePtr!(int) cui = UniquePtr!(const int).make(1);
const UniquePtr!(const int) cuci = UniquePtr!(const
int).make(1);
UniquePtr!(const int) uci = UniquePtr!(int).make(1);
UniquePtr!(int) ui = UniquePtr!(int).make(1);
const UniquePtr!(int) xcui = UniquePtr!(immutable
int).make(1);
const UniquePtr!(const int) xcuci = UniquePtr!(immutable
int).make(1);
}
```
This work but UniquePtr canno't be inside struct because
Segmentation fault.
How to pass a class by (const) reference to C++
In D I have an extern(C++) class:
```cpp
extern(C++) class A
{
~this();
// other stuff
}
```
An a function that takes A by const reference:
```cpp
void CppFunc(const A& arg);
```
But how do I bind this in D ?
```cpp
extern(C++) void CppFunc(A arg); // tries to pass as 'A*'
extern(C++) void CppFunc(ref const(A) arg); // tries to pass as
'A const * const &'
```
I have solved similar problems with other classes by declaring
them as struct in D, but that only works for classes that have no
virtual functions. I now have a class where I do need to use a
class on the D side, and now I have problems passing these
objects to C++.
Re: How to loop through characters of a string in D language?
On Saturday, 11 December 2021 at 09:25:37 UTC, Ola Fosheim Grøstad wrote: ```putchar(…)``` is too slow! On planet Mars maybe, but here on earth, my computer can do about 4 billion ticks per second, and my entire program (using putchar) takes only 3084 ticks.
Re: How to loop through characters of a string in D language?
On Monday, 13 December 2021 at 05:46:06 UTC, forkit wrote: On Saturday, 11 December 2021 at 09:25:37 UTC, Ola Fosheim Grøstad wrote: ```putchar(…)``` is too slow! On planet Mars maybe, but here on earth, my computer can do about 4 billion ticks per second, and my entire program (using putchar) takes only 3084 ticks. Can I borrow a couple of your ticks?
Re: How to pass a class by (const) reference to C++
On Sunday, 12 December 2021 at 21:24:39 UTC, Jan wrote:
In D I have an extern(C++) class:
```cpp
extern(C++) class A
{
~this();
// other stuff
}
```
An a function that takes A by const reference:
```cpp
void CppFunc(const A& arg);
```
But how do I bind this in D ?
```cpp
extern(C++) void CppFunc(A arg); // tries to pass as 'A*'
extern(C++) void CppFunc(ref const(A) arg); // tries to pass as
'A const * const &'
```
I have solved similar problems with other classes by declaring
them as struct in D, but that only works for classes that have
no virtual functions. I now have a class where I do need to use
a class on the D side, and now I have problems passing these
objects to C++.
You can tell compiler to mangle it as struct/class using
extern(C++, struct).
```d
extern (C++, struct) // will use struct mangling even though it's
a class
class SomeDClass
{
...
}
```
