Sergey Gromov wrote:
Mon, 27 Jul 2009 07:59:40 -0500, Andrei Alexandrescu wrote:
Is it appropriate to define multiple classes, structs, templates, etc
within a single module? What considerations should inform the decision
regarding the placement of module boundaries?
I think it's appropriate because many pieces of functionality come as a
bundle. The rule of thumb is, module provides the functionality, and
it's up to the designer to decide what that entails.
That's the problem. On one hand, it's desirable to see a module as a
functionality bundle. On the other hand, module is the smallest
available unit of encapsulation. That is, if you have a class and
change its private implementation, this may affect *anything* in the
same module. Hence Tango's hundreds of modules in dozens of packages, I
think.
I guess that's meant to encourage you to keep your modules small enough
that you know what you're doing.
At the smallest level, it would be a matter of: If in C++ you would
declare Qwert to be a friend of Yuiop, then in D you put Qwert and Yuiop
in the same module. You could implement the converse as well, but for a
bunch of small classes it usually isn't worth it.
It also adds to the problem that most people familiar with OO paradigm
consider classes to be such encapsulation units. Surprizes are
inevitable.
I once came up with the idea a 'veryprivate' protection attribute that
would do this, but I can't seem to find the post now.
Stewart.
