Re: the first version of abstract path manipulation c lass (interface)

From: ilv2fly2001 (mcr_at_[hidden])
Date: 2002-01-30 11:05:11

--- In boost_at_y..., "Stewart, Robert" <stewart_at_s...> wrote:
> From:	ilv2fly2001 [SMTP:mcr_at_y...]
> > 
> > > Perhaps that means we need a simpler, lower level class that
> > > manipulates a pathname or some portion of one, using a single
> > > case sensitivity/filesystem policy, and another, higher level
> > > class, that aggregates the simpler objects to create a logical
> > > pathname object that spans filesystems.
> 
> [snipped description of facet-based I/O of a path components
> collection]
> 
> That's the sort of thing I was alluding to, but there's still the
> need for the lower-level, somewhat more platform specific pathname
> manipulations.
>
> IOW, I'd still want to be able to write code that starts with a
> pathname-in-a-string like "some relative path/subdir/another
> subdir/filename.suffix" on the systems I use, even if that is
> parsed into some internal format and managed by cross-platform
> code thereafter.
> 

Absolutely, you should be able to do that, but it would be handled by 
a facet not by the container. 

What I was trying to suggest was that the container delagated all of 
its input/output through a facet. So, you could still make use of 
your pathname-in-a-string but as you pass it to the container it runs 
off to the assigned facet to parse, validate, normalize, and break it 
into the individual components.

Going in reverse and taking path components from the container would 
involve an output facet that would give you a component like 'foo/' 
or '/' or 'textfile.txt' depending on what component you where asking 
for.

IOW, all the smarts needed to work on a platform specific basis are 
in facets (probably some policy based design) not the container. The 
container itself enables you to access the individual parts 
positionally and hides all the gory details of using the facets from 
the library user.

I'm probably not being as clear as I could be, I'm typing this up 
inbetween meetings and nonstop office interruptions.