Subject: Re: namestring to pathname and back From: Erik Naggum <erik@naggum.no> Date: 1999/08/22 Newsgroups: comp.lang.lisp Message-ID: <3144346992163159@naggum.no> * Vassil Nikolov <van@einet.bg> | Now, the question is, can I be sure that this second string would be | identical to the first string that was passed to CL:OPEN? there is an infinite number of strings that name exactly the same file under Unix. I don't think it is even remotely reasonable to expect that the same filename will be returned from a function that has to figure out the full pathname corresponding to a filename. after all, the operating systems doesn't even _know_ the filename -- all it cares about is a device and an inode number. now, if the operating system actually knew the filename, or even the full pathname, you could ask it and get back a value that you could ask your question about. lacking such functionality in all Unixen, your question is implementationally meaningless. there is also an infinite number of namestrings that may be parsed into the same pathname and vice versa, so there cannot be such a guarantee in the general case. the interesting questions are (1) for which namestrings and pathnames there exists a guarantee, and (2) whether such a guarantee can be established algorithmically for a given namestring without actually consulting the operating system. #:Erik -- (defun pringles (chips) (loop (pop chips)))