[boost] Re: [filesystem] status() if neither file nor directory?

From: Beman Dawes (bdawes_at_[hidden])
Date: 2005-05-08 12:31:07

"Peter Dimov" <pdimov_at_[hidden]> wrote in message 
news:012701c553ea$c2707610$6401a8c0_at_pdimov2...
> Beman Dawes wrote:
>
>> 1) Add an other_flag and a matching is_other() function. Change
>> definition of exists() to status() & 
>> (directory_flag|file_flag|other_flag)
>
> An entity that is not file or directory should just return false from 
> is_file and is_directory. There are no operations defined on "other", so 
> the category and the corresponding predicate are useless.
>
> It seems to me that the correct definition of exists() in terms of 
> status() is just !(status() & not_found_flag).

The expectation with not_found_flag is that, assuming the branch() if any is 
found, it should be possible to create a file or directory with that path. 
Consider:

   if (!exists("foo"))
      create_directory("foo");  // surprise! This may fail: "exists but not 
a directory"

That seems pretty strange to me.

--Beman