[path-PEP] Path inherits from basestring again

[Ron Adam]

Michael Hoffman wrote:
> Ron Adam wrote:
> 
>> In all current cases, (that I know of), of differing types, '+' raises 
>> an error.
> 
> 
> Not quite:
> 
>  >>> "hello " + u"world"
> u'hello world'
>  >>> 4.5 + 5
> 9.5
> 
>> Question:  Is a path object mutable?
> 
> 
> No.
> 
> This should answer the rest of your questions.

Yes it does, thanks.

In the case of numeric types, it's an addition and not a join.  I should 
have specified in 'all cases, (I know of), where '+' is used to join 
objects, but I thought that was clear from the context of the 
discussion.  I haven't needed to use unicode yet, so it didn't come to mind.


Although it raises other questions...  ;-)

Could a string prefix be used with paths as well?

    path = p"C://somedir//somefile"


Would that clash with the 'u' prefix?  Or would we need a 'p' and a 'up' 
prefix to differentiate the two?
	
(Just a thought. I'm +0 on this, but this seems to be a new string type, 
and file operations are frequent and common.)



You could have both behaviors with the '+'.

     path_a + path_b  ->  join path_b to path_a using separator.

     path + string ->  append string to path (no separator)

     string + path ->  prepends string to path (no separator)


This would be similar, (but not exactly like), how u'text'+'text' and 
'text'+u'text' work.  They both return unicode strings given a standard 
string.  It would allow the following to work.


     path = path('C:')+path('somedir')+path('somefile.txt')+'.zip'

     ->>   'C://somedir//somefile.txt.zip'



So I guess the question here is which of these is preferable with '+'?

1.  Strings act like paths when one is a path.  They will be joined with 
a separator.

2.  Paths are joined with separators *and* a string is prepended or 
postpended "as is" with no separator.

3.  All path objects (and strings) act like strings.  No separator is 
used when joining path objects with '+'.


(Seems like #3 defeats the purpose of path a bit to me.)


I'm +1 on #2 after thinking about it.

Cheers,
Ron