On Saturday, 18 May 2013 at 22:23:51 UTC, Igor Stepanov wrote:
At the current time D have powerful mechanism of access to C++
classes.
For access to methods of C++ classes (virtual and not) we can
use extern(C++) interface.
//С++
class CPPTest1
{
int a;
int b;
public:
virtual int boom();
int fun();
static int gun();
CPPTest1(int);
virtual ~CPPTest1();
int& operator[](size_t);
};
class CPPTest2: public CPPTest1
{
int boom();
};
//D
extern(C++)interface CPPTest1
{
int boom();
static int gun();
final int fun();
}
extern(C++)interface CPPTest2: CPPTest1
{
//int boom();
}
As a rule, non-static fields are not public in C++ classes and
is not part of interface. Thus the most of C++ classes can be
bound without any glue c++ code.
However D dont support C++ overloaded operators and
constructors. Yes, we cannot make mapping C++ operators to D
operators and C++ constructors to D constructors). Nonetheless
С++ operators and constructors are the simple C++ functions or
methods with special mangling. Thus I've suggest next mechanism:
Allow special pragma(cppSymbol, string_arg), when string_arg is
the name of c++ thing.
Example:
extern(C++)interface CPPTest1
{
int boom();
static int gun();
final int fun();
///!!!!
pragma(cppSymbol, "constructor") final void ctor(int);
//linked with CPPTest1(int);
pragma(cppSymbol, "destructor") void dtor(); //linked with
virtual ~CPPTest1();
pragma(cppSymbol, "[]") ref int indexOf(size_t); //linked
with int& operator[](size_t);
}
This pragma must apply to the function (or method), use natural
C++ mangle, but set operatror or constructor or destructor
mangled name instead of function name.
Is it useful idea?
Isn't it possible already with something like:
extern(C++) interface Foo
{
pragma(mangle, typeof(this).mangleof ~
generateCPPMangle!"myOwnFunctionMangling") void foo();
}
AFAIK, mangle pragma was merged recently.