new DIP47: Outlining member functions of aggregates

[H. S. Teoh]

On Sun, Sep 08, 2013 at 02:53:10PM +0200, Dicebot wrote:
> On Sunday, 8 September 2013 at 12:46:49 UTC, Gary Willoughby wrote:
[...]
> >Seriously, this goes against everything you learn as a programmer,
> >nothing should ever be typed twice and then to say that the
> >declaration and implementation could be different just boggles my
> >mind?!?! Great more work!
> 
> It is no different from overriding `interface` methods in class.
> From the code structure point of view, declaration is interface.
> Implementation is implementation. Keeping those separate may
> sometimes/often be useful.
[...]

I agree that declaration is interface, and implementation is
implementation, and that it's good to separate them.  What I *don't*
agree with is that the interface should be *manually* maintained.  There
is absolutely no reason, in this day and age, that something so trivial
as extracting the interface *automatically* and *reliably* by the
compiler, can't be done.

Therefore, the *real* solution to this problem is to fix the compiler's
.di output to give a proper overview of the class *automatically*, and
nicely pretty-printed.  Manu has already said that the whole motivation
behind wanting this sort of interface/implementation separation was to
be able to tell what a class does at a glance. Well guess what? If we
clean up the current messy .di generation to produce something decent,
then all you have to do is to run dmd -H, and you have your at-a-glance
version of the class.  No unnecessary complication of the language, no
maintenance nightmare, no code duplication, very little implementation
effort, and 100% reliable because the .di file is generated straight
from the implementation, and therefore by definition is correct.

*This* is the correct solution to Manu's issue, IMO. DIP47 is
approaching it from a completely wrong angle. Please, let's not go back
to the C++ way. We've abandoned that a long time ago, and for good
reason. That bridge should've been burned already.


T

-- 
INTEL = Only half of "intelligence".