[Python-Dev] Path inherits from string (original) (raw)

Ian Bicking ianb at colorstudy.com
Thu Jan 26 18:00:04 CET 2006

Fredrik Lundh wrote:

However, I might be wrong because according to [1] it should work. And having to wrap the Path object in str() (open(str(somepath))) each and every time the called function expects a string is not a practical solution.

in Python, the usual way to access an attribute of an object is to access the attribute; e.g. f = open(p.name)

You mean "f = open(Path(p).name)", because it is likely that people will also have to accept strings for the nearterm (and probably longeterm) future. And the error message without will be inscrutable (and will still be inscrutable in many cases when you try to access other methods, sadly). And currently .name is taken for something else in the API. And the string path is not really an attribute because the string path is the object, it is not part of the object.

OTOH, str(path) will break unicode filenames. And unicode() breaks anything that simply desires to pass data through without effecting its encoding.

An open method on paths simplifies many of these issues, but doesn't do anything for passing a path to legacy code. Changing open() and all the functions that Path replaces (e.g., os.path.join) to accept Path objects may resolve issues with a substantial portion of code. But any code that does a typecheck on arguments will be broken -- which in the case of paths is quite common since many functions take both filename and file object arguments.

-- Ian Bicking / ianb at colorstudy.com / http://blog.ianbicking.org

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