RE: [boost] filesystem/directory example [was: ... header redux]

From: Beman Dawes (bdawes_at_[hidden])
Date: 2002-04-11 07:38:37

At 02:13 PM 4/9/2002, Stewart, Robert wrote:

 >From: Beman Dawes [mailto:bdawes_at_[hidden]]
 >>
 >> Notice the find_file function:
 >>
 >> //  find_file  ------------------------------------------//
 >> //  given a directory to recursively search
 >>
 >>    bool find_file( const string & dir_path, const string & name,
 >>      string & path_found, const string & ignore_dir_named="" )
 >
 >In my experience, output parameters such as path_found, are better put
 >first
 >in the argument list, so they are grouped -- should there be more than 
one
 >-- and so they are always in an expected position.  I tried putting them
 >last, but that interfered with default arguments.  Putting them first 
also
 >associates them with the return value of the function (in a manner of
 >speaking, anyway).

I also used to put the output parameters first, but then the STL got me 
doing it the other way around. I think on balance I like output first, for 
the reasons you mention.

 >(I'm mentioning this so that you consider it for find_file() but also any
 >other functions you may write for the library.)

I really tried to write the example program as if it was just another 
script I needed, and thus did not agonize of style.

For example, should some of the other functions return a bool, rather than 
a string which gets set to "" on failure?  I didn't worry about it.  The 
point being to get a feel for usage in a real program, not a demonstration 
piece.

So, to get back to your point, we should definitely look at that sort of 
issue if we decide to add such a function to Boost.

 >Looking at this code, I find myself a bit confused by the terminology you
 >have selected.  I was troubled when I read your list (on the filesystem
 >design page you posted), but didn't quite know what was wrong.

I'm not entirely happy with terminology either.

I spent some time reading the POSIX definitions at 
http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap03.html

I really don't see them as any less confusing, although it might be better 
to just go with a standardized terminology. So for now, exact terminology 
remains an open issue.

Thanks,

--Beman