C++ constructors, destructors and operator access
nazriel
spam at dzfl.pl
Mon May 20 13:11:25 PDT 2013
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.
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