A single path is not conceptually a "range" of anything — it's just a single filesystem path.

C++17 made the mistake of giving "begin" and "end" methods to `std::filesystem::path`, so that to C++ a std::filesystem::path looks like a range of paths.

What it should have done was to give `std::filesystem::path` one or more "range accessor" methods:

for (auto&& component : mypath.components()) { ... }

for (auto&& character : mypath.str()) { ... }

Niall, if you are actively pursuing `path_view` for C++2b, please try to avoid making the same mistakes that <filesystem> made!

Thanks,

–Arthur

On Thu, Aug 22, 2019 at 9:45 AM Herring, Davis via Lib-Ext <lib-ext@lists.isocpp.org> wrote:

> It has been brought to my attention by Victor Zverovich that
> filesystem::path has an unfortunate quirk wrt Ranges:
> filesystem::path::iterator::value_type is filesystem::path.

This was (my) Late 19 comment for C++17. (At the time, I proposed just using string for the individual components, but it's still helpful to have path's encoding support.) It's also a famous pitfall in Python:

def depth(x,f): # apply f to all leaves
try: x=iter(x)
except TypeError: f(x)
else:
for e in x: depth(e,f)

depth("a",id) will recurse forever because list("a")[0]=="a".

Davis
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