PEP on path module for standard library

[Ron Adam]

Bengt Richter wrote:


> <indulging what="my penchant for seeking the general behind the specific ;-)" >

<fold>

> 
> Say, how about
> 
>     if Pathobject('gui://message_box/yn/continue processing?').open().read().lower()!='y':
>         raise SystemExit, "Ok, really not continuing ;-)"
> 
> An appropriate registered subclass for the given platform, returned when the
> Pathobject base class instantiates and looks at the first element on open() and delegates
> would make that possible, and spelled platform-independently as in the code above.

I like it.  ;-)

No reason why a path can't be associated to any tree based object.

> </indulging>
> 
> Regards,
> Bengt Richter

<more indulging>

I wasn't sure what to comment on, but it does point out some interesting 
possibilities I think.

A path could be associated to any file-like object in an external (or 
internal) tree structure.  I don't see any reason why not.

In the case of an internal file-like object, it could be a series of 
keys in nested dictionaries.  Why not use a path as a dictionary 
interface?

So it sort of raises the question of how tightly a path object should be 
associated to a data structure?  When and where should the path object 
determine what the final path form should be?  And how smart should it 
be as a potential file-like object?

Currently the device name is considered part of the path, but if instead 
you treat the device as an object, it could open up more options.

(Which would extend the pattern of your example above. I think.)

(also a sketch..  so something like...)

    # Initiate a device path object.
    apath = device('C:').path(initial_path)

    # Use it to get and put data
    afile = apath.open(mode,position,units)  # defaults ('r','line',next)
    aline = afile.read().next()    # read next unit, or as an iterator.
    afile.write(line)
    afile.close()

    # Manually manipulate the path
    apath.append('something')	  # add to end of path
    apath.remove()		  # remove end of path
    alist = apath.split()          # convert to a list
    apath.join(alist)		  # convert list to a path
    astring = str(apath())         # get string from path
    apath('astring')		  # set path to string
    apath.validate()               # make sure it's valid

    # Iterate and navigate the path
    apath.next()			# iterate path objects
    apath.next(search_string)    # iterate with search string
    apath.previous()		# go back
    apath.enter()		# enter directory
    apath.exit()			# exit directory

    # Close it when done.
    apath.close()

    etc...


With this you can iterate a file system as well as it's files.  ;-) 

     (Add more or less methods as needed of course.)


    apath = device(dev_obj).path(some_path_sting)
    apath.open().write(data).close()


or if you like...

    device(dev_obj).append(path_sting).open().write(data).close()



Just a few thoughts,

Cheers,
Ron