That would be nice, but as others hinted that wouldn't actually work:
* there are paths without a file_name (`/`) so it returns an Option to make that evident
* to_str attempts to convert the OS-dependent thing to a Rust string. Rust strings are valid unicode, but many filesystems don't have such strict requirements[0]. Again Rust returns an Option to makes that evident although there's a "to_string_lossy" method which will simply replace invalid sequences with U+FFFD if you don't really care
The Rust philosophy is generally to expose these issues upfront and force the developer to consider them (and either handle or explicitly ignore them). It is indubitably less convenient than e.g. Python 3's `PurePath(app_path).name` returning an str, but you'll have had to decide what happens in case of failure.
Paths are really a good example of something which looks simple, should be simple, and is actually anything but simple for historical and technical reasons, especially in a cross-platform context.
[0]
* Unix paths are the most troublesome: they're arbitrary bags of (non-NUL) bytes, they don't have to be in a known encoding, they don't have to be in any encoding.
* Windows paths are not guaranteed to be Unicode either: they're UTF-16 code units aka UCS2 + surrogates, and the surrogates may be unpaired, leading to invalid Unicode.
Also, OSX applies unicode normalization to the filenames, which can cause some interoperability problems with unix, e.g. you try to copy files forth and back between the systems and end up with two copies of a file, with identical-looking filenames that differ in their unicode normal form.
That would be nice, but as others hinted that wouldn't actually work:
* there are paths without a file_name (`/`) so it returns an Option to make that evident
* to_str attempts to convert the OS-dependent thing to a Rust string. Rust strings are valid unicode, but many filesystems don't have such strict requirements[0]. Again Rust returns an Option to makes that evident although there's a "to_string_lossy" method which will simply replace invalid sequences with U+FFFD if you don't really care
The Rust philosophy is generally to expose these issues upfront and force the developer to consider them (and either handle or explicitly ignore them). It is indubitably less convenient than e.g. Python 3's `PurePath(app_path).name` returning an str, but you'll have had to decide what happens in case of failure.
Paths are really a good example of something which looks simple, should be simple, and is actually anything but simple for historical and technical reasons, especially in a cross-platform context.
[0]
* Unix paths are the most troublesome: they're arbitrary bags of (non-NUL) bytes, they don't have to be in a known encoding, they don't have to be in any encoding.
* Windows paths are not guaranteed to be Unicode either: they're UTF-16 code units aka UCS2 + surrogates, and the surrogates may be unpaired, leading to invalid Unicode.
* OSX paths are guaranteed to be valid Unicode.