No header files?

[AJ]

"Steven Schveighoffer" <schveiguy at yahoo.com> wrote in message 
news:op.u15929x0eav7ka at localhost.localdomain...
> On Wed, 21 Oct 2009 18:16:48 -0400, AJ <aj at nospam.net> wrote:
>
>>
>> "Steven Schveighoffer" <schveiguy at yahoo.com> wrote in message
>> news:op.u157hfkveav7ka at localhost.localdomain...
>>> On Wed, 21 Oct 2009 17:59:52 -0400, AJ <aj at nospam.net> wrote:
>>>
>>>> Since D has no header files, how does one create "a library" that 
>>>> another
>>>> developer can use without exposing the implementation?
>>>
>>> try dmd -H.
>>>
>>> .di files are D header files, basically used for the reason you specify.
>>
>> OK, so header files can be generated. The thing is though, when I am
>> designing at the code level, I start with the declarations (such as class
>> data members and methods) and do the implementation (or one can hand it 
>> off
>> to someone else) afterwards. That serves as the "blue print" for further
>> development and remains as first level of documentation as well. Working
>> with just "implementation files" seems to be putting the cart before the
>> horse. While eliminating something unnecessary is something to strive 
>> for, I
>> don't think header files are unnecessary in the development process 
>> (i.e., I
>> don't think that relegating them to just the situation given with my OP 
>> is
>> good, exactly for the reasons of usefullness I gave).
>
> Separating interface from implementation is good -- but not if you have to 
> repeat the interface (as you do with C++ or C).

I wouldn't use the term "interface" in this context for it has other meaning 
in OO.

> What happens (and being a  long-time C++ developer, I've had my fair share 
> of experience with it) is  that the interface gets out of sync with the 
> implementation, so weird shit  happens.
>
> I even think d's "editable" interface files are suspect.  They can be out 
> of sync with the object files, and then you have the same problem.  The 
> best model by far is Java and C# where the object files *are* the 
> interface files.  Then you only have to worry about documentation being 
> out of sync.  But at least your programs don't crash randomly for no 
> reason because the docs are invalid.
>
> What I would suggest is creating stub functions via {} and then when you 
> go back to fill in the interface, fill in the {} area.  You get the same 
> effect.

You lose the ability to use, say a class declaration, as the specification 
(at least without a sophisitcated, code-folding/code-formatting IDE).