On 2009-11-29 18:03:40 -0500, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> said:
Walter and I just discussed the matter of inheriting constructors. Our
thought on the issue:
a) If a class doesn't define any constructors and adds no fields,
inherit constructors. Example:
class MyException : Exception {}
b) If a class defines at least one constructor, do not inherit constructors.
c) If a class doesn't define any constructors but does add at least a
non-static field -> undecided.
What do you think?
Objective-C has 'a' and 'c' acting like 'a'. There's no 'b' though, and
this is a small annoyance, as "constructors" in Objective-C are just
normal methods with a name that starts with "init".
Personally, I'd say adding a field to a class shouldn't affect its
constructor. If you need to initialize the field at object's
construction, then you add a constructor. But otherwise, if you don't
need to initialize it at construction (which happens fairly often when
fields are zeroed anyway), then you can certainly inherit super's
constructors.
In fact, I find it hard to see a justification for making adding a
field break constructor inheritance. My experience with Objective-C
tells me that 'c' acting like 'a' wouldn't be a problem at all because
D, just like Objective-C, initializes all fields to a default value
anyway. You only need a constructor when you want a non-default value
in a field.
--
Michel Fortin
michel.for...@michelf.com
http://michelf.com/
