• MarisaLovesUsAll (12/12) Mar 23 2014 Hi! I didn't find how to implement functions outside the class,
• bearophile (5/12) Mar 23 2014 It's not possible. Some people want it to happen, some other
• John Colvin (33/45) Mar 23 2014 No, it's not possible.
• John Colvin (2/22) Mar 23 2014 sorry, 2 features.
• Matej Nanut (19/19) Mar 23 2014 Hello!
• MarisaLovesUsAll (14/38) Mar 24 2014 2 all:
• Steven Schveighoffer (10/50) Mar 24 2014 Implementation outside the class is not exactly possible, but it IS
• Rikki Cattermole (22/34) Mar 24 2014 There is one way that could be made far nicer with templates and

"MarisaLovesUsAll" <marusya 2ch.hk> writes:

Hi! I didn't find how to implement functions outside the class, 
like in C++.

C++:
class MyClass
{
    void myFunc();
};
void MyClass::myFunc() { ... }

Is it possible to do this in D ?


Sorry for my bad English.
Regards,
Alexey

"bearophile" <bearophileHUGS lycos.com> writes:

MarisaLovesUsAll:

 C++:
 class MyClass
 {
    void myFunc();
 };
 void MyClass::myFunc() { ... }

 Is it possible to do this in D ?

It's not possible. Some people want it to happen, some other 
people hate it.

Bye,
bearophile

"John Colvin" <john.loughran.colvin gmail.com> writes:

On Sunday, 23 March 2014 at 21:48:33 UTC, MarisaLovesUsAll wrote:
 Hi! I didn't find how to implement functions outside the class, 
 like in C++.

 C++:
 class MyClass
 {
    void myFunc();
 };
 void MyClass::myFunc() { ... }

 Is it possible to do this in D ?


 Sorry for my bad English.
 Regards,
 Alexey

No, it's not possible.

However, Combining these 3 features:


UFCS (universal function call syntax, foo(x) can be rewritten as 
x.foo() )

private means private to the module, not private to the class

//one.d
module one;

class A
{
     private int i;
}

int getI(A c)
{
     return c.i;
}

//two.d
module two;

void main()
{
     auto a = new A;
     auto i = A.getI();
     assert(i == int.init);
}


Note that:

getI is just a normal function. It can still be called like 
getI(a);. This means they by definition aren't virtual and cannot 
override inherited methods.

the same syntax works for anything, not just classes. E.g. 
core.time.msecs can be called like this:
auto t = 42.msecs();
instead of this:
auto t = msecs(42);

"John Colvin" <john.loughran.colvin gmail.com> writes:

On Sunday, 23 March 2014 at 22:20:39 UTC, John Colvin wrote:
 On Sunday, 23 March 2014 at 21:48:33 UTC, MarisaLovesUsAll 
 wrote:
 Hi! I didn't find how to implement functions outside the 
 class, like in C++.

 C++:
 class MyClass
 {
   void myFunc();
 };
 void MyClass::myFunc() { ... }

 Is it possible to do this in D ?


 Sorry for my bad English.
 Regards,
 Alexey

 No, it's not possible.

 However, Combining these 3 features:

sorry, 2 features.

Matej Nanut <matejnanut gmail.com> writes:

Hello!

You can implement static functions that act like members, like so:

---
void myFunc(MyClass c) { ... }
---

Which you will be able to call like:

---
auto c = new MyClass();
c.myFunc();
---

because of uniform function call syntax (UFCS).

But they won't be real methods (virtual member functions), which means they
can't be overridden.

Note that you can use the class's private members in such functions,
because private things in D are private to the file (module) instead of the
containing class or struct.

I don't think it's possible to do the same thing as in C++ though; but I
might be wrong.

Why would you like to do that?

"MarisaLovesUsAll" <marusya 2ch.hk> writes:

On Monday, 24 March 2014 at 01:34:22 UTC, Matej Nanut wrote:
 Hello!

 You can implement static functions that act like members, like 
 so:

 ---
 void myFunc(MyClass c) { ... }
 ---

 Which you will be able to call like:

 ---
 auto c = new MyClass();
 c.myFunc();
 ---

 because of uniform function call syntax (UFCS).

 But they won't be real methods (virtual member functions), 
 which means they
 can't be overridden.

 Note that you can use the class's private members in such 
 functions,
 because private things in D are private to the file (module) 
 instead of the
 containing class or struct.

 I don't think it's possible to do the same thing as in C++ 
 though; but I
 might be wrong.

2 all:
Thanks for replies!

 Why would you like to do that?

I planned to use it to take event handling out from class (and 
put it in another file), but now I see that isn't a good idea.
class App
{
     void updateEvents(SDL_Event event) { ... }
}


By the way, it would be useful if it was written somewhere that 
implementation outside the class is impossible.

Sorry for bad English.
Regards,
Alexey

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Mon, 24 Mar 2014 16:02:25 -0400, MarisaLovesUsAll <marusya 2ch.hk>  
wrote:

 On Monday, 24 March 2014 at 01:34:22 UTC, Matej Nanut wrote:
 Hello!

 You can implement static functions that act like members, like so:

 ---
 void myFunc(MyClass c) { ... }
 ---

 Which you will be able to call like:

 ---
 auto c = new MyClass();
 c.myFunc();
 ---

 because of uniform function call syntax (UFCS).

 But they won't be real methods (virtual member functions), which means  
 they
 can't be overridden.

 Note that you can use the class's private members in such functions,
 because private things in D are private to the file (module) instead of  
 the
 containing class or struct.

 I don't think it's possible to do the same thing as in C++ though; but I
 might be wrong.

 2 all:
 Thanks for replies!

 Why would you like to do that?

 I planned to use it to take event handling out from class (and put it in  
 another file), but now I see that isn't a good idea.
 class App
 {
      void updateEvents(SDL_Event event) { ... }
 }


 By the way, it would be useful if it was written somewhere that  
 implementation outside the class is impossible.

Implementation outside the class is not exactly possible, but it IS  
possible to separate declaration from implementation, see D interface  
(.di) files. You can't split an implementation into two files, however.

Note, there are serious drawbacks for using an interface file, most  
importantly eliminating the ability to inline. It should only be used,  
IMO, when you need to hide the implementation, as in a closed-source  
project.

-Steve

"Rikki Cattermole" <alphaglosined gmail.com> writes:

On Sunday, 23 March 2014 at 21:48:33 UTC, MarisaLovesUsAll wrote:
 Hi! I didn't find how to implement functions outside the class, 
 like in C++.

 C++:
 class MyClass
 {
    void myFunc();
 };
 void MyClass::myFunc() { ... }

 Is it possible to do this in D ?


 Sorry for my bad English.
 Regards,
 Alexey

There is one way that could be made far nicer with templates and 
traits but..

import std.stdio;

alias void delegate() testfunc;

class T {
	this() {
		test = () { test_(this); };	
	}
	
	
	testfunc test;
}

void test_(T t) {
	writeln("hi from test");
}

void main() {
	T t = new T();
	t.test();
}

There will be other ways to make this nicer. If you feel you 
really really want this sort of thing (advised not to).