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digitalmars.D.learn - Function definition in multiple modules

reply Martin Drasar <drasar ics.muni.cz> writes:
Hi,

I have a class that implements a lot of interfaces and I would like to
separate the definition into different files, i.e. implementation of one
interface in one file. Something akin to this C++ code:

a.cpp:

class A
{
  void b();
  void c();
};

b.cpp:

void A::b() {}

c.cpp:

void A::c() {}

Is there a way to do it in D easily? Do I have to use UFCS?

Thanks,
Martin
Mar 29 2012
parent reply simendsjo <simendsjo gmail.com> writes:
On Thu, 29 Mar 2012 10:33:03 +0200, Martin Drasar <drasar ics.muni.cz>  
wrote:


 Hi,

 I have a class that implements a lot of interfaces and I would like to
 separate the definition into different files, i.e. implementation of one
 interface in one file. Something akin to this C++ code:

 a.cpp:

 class A
 {
   void b();
   void c();
 };

 b.cpp:

 void A::b() {}

 c.cpp:

 void A::c() {}

 Is there a way to do it in D easily? Do I have to use UFCS?

 Thanks,
 Martin


D has interface files, .di. These can be automatically generated by the  
compiler using the -H switch.

So you code your class normally:
a.d:
class A
{
     void a() {}
     void b() {}
}

$ dmd -H a.d
$ cat a.di
// D import file generated from 'a.d'
class A
{
     void a()
{
}
     void b()
{
}
}
Mar 29 2012
parent reply Martin Drasar <drasar ics.muni.cz> writes:
On 29.3.2012 11:16, simendsjo wrote:

 
 D has interface files, .di. These can be automatically generated by the
 compiler using the -H switch.
 
 So you code your class normally:
 a.d:
 class A
 {
     void a() {}
     void b() {}
 }
 
 $ dmd -H a.d
 $ cat a.di
 // D import file generated from 'a.d'
 class A
 {
     void a()
 {
 }
     void b()
 {
 }
 }


Hi,

I have probably not made myslef clear.

Let's say I have this D code:

interfaces.d:
interface IA
{
  void a();
}

interface IB
{
  void b();
}

myfunkyclass.d:
import interfaces;
class X : IA, IB
{
  void a()
  {
  }

  void b()
  {
  }
}

I would like to split the X class definition into two files. One file
would implement methods of interface IA and another of interface IB. So
it would be like this:

myfunkyclassIA.d:
class X : IA, IB
{
  void a()
  {
  }
}

myfunkyclassIB.d:
void b(X x)
{
}

Except using UFCS in this case does not work...

Martin
Mar 29 2012
parent reply simendsjo <simendsjo gmail.com> writes:
On Thu, 29 Mar 2012 11:31:57 +0200, Martin Drasar <drasar ics.muni.cz>  
wrote:


 On 29.3.2012 11:16, simendsjo wrote:

 D has interface files, .di. These can be automatically generated by the
 compiler using the -H switch.




(snip)

 I would like to split the X class definition into two files. One file
 would implement methods of interface IA and another of interface IB. So
 it would be like this:

 myfunkyclassIA.d:
 class X : IA, IB
 {
   void a()
   {
   }
 }

 myfunkyclassIB.d:
 void b(X x)
 {
 }

 Except using UFCS in this case does not work...

 Martin


Your looking for partial classes? D doesn't have this as far as I know.

"alias this" should work for more than one value in the future, and then  
(I think) you should be able to do something like this:

class XIB : IB {}
class XIA : IA {}
class X : IA, IB {
   XIA xia;
   XIB xib;
   alias xia this;
   alias xib this;
}

But you can also solve it with mixin templates:
mixin template XIA {
   // all IA methods
}
mixin template XIB {
   // all IB methods
}

class X : IA, IB {
   mixin XIA!();
   mixin XIB!();
}
Mar 29 2012
parent reply Martin Drasar <drasar ics.muni.cz> writes:
On 29.3.2012 12:02, simendsjo wrote:

 Your looking for partial classes? D doesn't have this as far as I know.
 
 "alias this" should work for more than one value in the future, and then
 (I think) you should be able to do something like this:
 
 class XIB : IB {}
 class XIA : IA {}
 class X : IA, IB {
   XIA xia;
   XIB xib;
   alias xia this;
   alias xib this;
 }


I was thinking about similar idea. But instead of alias this I intended
to write something like this:

class X : IA, IB {
  XIA xia;

  void iamethod()
  {
    xia.iamethod();
  }
  ...
}

It is not very pretty though...


 But you can also solve it with mixin templates:
 mixin template XIA {
   // all IA methods
 }
 mixin template XIB {
   // all IB methods
 }
 
 class X : IA, IB {
   mixin XIA!();
   mixin XIB!();
 }


This would make the code separation easy to manage, but I am concerned
about debugging. How is e.g. gdb able to debug mixins? I think I have
read somewhere in the D or D-learn, that the dmd can produce the file
with mixed-in code for the debugger, but I am not sure how to find it.

Martin
Mar 29 2012
parent reply simendsjo <simendsjo gmail.com> writes:
On Thu, 29 Mar 2012 12:58:56 +0200, Martin Drasar <drasar ics.muni.cz>  
wrote:


 On 29.3.2012 12:02, simendsjo wrote:

 Your looking for partial classes? D doesn't have this as far as I know.

 "alias this" should work for more than one value in the future, and then
 (I think) you should be able to do something like this:

 class XIB : IB {}
 class XIA : IA {}
 class X : IA, IB {
   XIA xia;
   XIB xib;
   alias xia this;
   alias xib this;
 }


 I was thinking about similar idea. But instead of alias this I intended
 to write something like this:

 class X : IA, IB {
   XIA xia;

   void iamethod()
   {
     xia.iamethod();
   }
   ...
 }


You can also use opDispatch and __traits(getMember, ..). Don't know if it  
works when implementing interfaces though.


 It is not very pretty though...


 But you can also solve it with mixin templates:
 mixin template XIA {
   // all IA methods
 }
 mixin template XIB {
   // all IB methods
 }

 class X : IA, IB {
   mixin XIA!();
   mixin XIB!();
 }


 This would make the code separation easy to manage, but I am concerned
 about debugging. How is e.g. gdb able to debug mixins? I think I have
 read somewhere in the D or D-learn, that the dmd can produce the file
 with mixed-in code for the debugger, but I am not sure how to find it.

 Martin


It's not string mixins:
mixin template XIA() {
   void a() { ... } // regular function
}
class X : IA {
   mixin XIA!()
}

XIA is injected into X, so X now looks like
class X : IA {
   void a() { ... }
}
Mar 29 2012
parent Martin Drasar <drasar ics.muni.cz> writes:
On 29.3.2012 13:05, simendsjo wrote:

 It's not string mixins:
 mixin template XIA() {
   void a() { ... } // regular function
 }
 class X : IA {
   mixin XIA!()
 }
 
 XIA is injected into X, so X now looks like
 class X : IA {
   void a() { ... }
 }


I should have thought and experiment more before writing. Did a quick
test and the gdb jumps nicely into the mixin template. So the debugging
is a breeze.

Thanks simendsjo for your help. I think that I know now everything I needed.

Regards
Martin
Mar 29 2012