On Thursday, 16 August 2012 at 14:58:23 UTC, R Grocott wrote:
C++'s fragile ABI makes it very difficult to write class
libraries without some sort of workaround. For example,
RapidXML and AGG are distributed as source code; GDI+ is a
header-only wrapper over an underlying C interface; and Qt
makes heavy use of the Pimpl idiom, which makes its source code
much more complex than it needs to be. This is also a major
problem for any program which wants to expose a plugin API.
Since pimpl is useful but messy, given D's metaprogramming
capabilities, maybe what we need is a Pimpl template in Phobos:
// The implementation struct.
struct SImpl {
int a, b, c;
void fun() {}
}
// Automatically generate code for the Pimpl wrapper.
alias Pimpl!SImpl S;
auto s = new S;
On the other hand, IIUC Pimpl doesn't solve the vtable part of
the problem, only the data members part. (Correct me if I'm
wrong here, since I admit to knowing very little about the
fragile ABI problem or its workarounds.)
