On Jan 7, 2022, at 11:35 PM, pd-list-request@lists.iem.at wrote:

If you want to resolve an 
existing file using Pd's canvas: use [file which]. If you want create
a 
new file relative to the patch, use [dir( -> [pdcontrol].

That's what I do now. That's the easy part. The less easy part is
reliably detecting whether a given path is relative. But knowing that
even Pd does it somewhat clumsily, I'll stick to the clumsy solution
(checking for / and :).