From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-05-08 16:53:16
Beman Dawes wrote:
>> A hypothetical OS that allows directories to be opened with an
>> ifstream may reasonably answer true to both is_stream(p) and
>> is_directory(p). Or maybe not. :-)
> I think not. Dividing the world into non-overlapping categories is
> much easier:-)
It's only easier until an example comes up that doesn't fit the scheme, so
you are forced to invent meta-categories (also known as "hacks" in some
category theory circles) such as "other". :-)
"Capability bits" are cleaner. Is it openable with ifstream? file_bit. Is it
iteratable with directory_iterator? directory_bit. Does it exist?
!not_found_bit. When a socket is thrown your way, you just run it by the
list and conclude that no bit needs to be set.
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