On Tuesday, 8 July 2014 at 10:47:26 UTC, NoUseForAName wrote:
Also side question. What are these .di files? D propaganda
radio told me that D does not need header files because it has
a real module system (like e.g. Pascal or Go) yet in the
solution Ali posted these .di files seem to be.. pretty much
like C header files.
They are optional, for those situations when you don't want to
distribute the entire source code (e.g. proprietary library
distributed in binary form). They are usually auto-generated by
the compiler (dmd -H), and I agree that it's awkward to have to
define them manually.
So I could just put..
public struct S;
private struct S
{
int i;
}
.. in the .d file and that would work? I mean I expected
something like this but then why would Ali post such a complex
solution?
I guess because it's a (the only?) way to get real incomplete
types. It is the most "literal" translation of what you
described. But of course, there are better ways to achieve what
you actually want.
Your example above doesn't work, because it would be interpreted
as a redefinition of the struct. Instead, you can use a public
alias to a private type:
// my_module.d:
private struct MyStructImpl {
int x;
}
public alias MyStructPtr = MyStructImpl*;
void doSomething(MyStructPtr foo) {
...
}
// my_main_program.d:
MyStructPtr bar; // OK
MyStructImpl foo; // Error: my_module.MyStructImpl is private
