On 6/15/10 2:05 PM, Alessio Stalla wrote:
[…]
Eliminating the problem in the general case is harder and we'd better discuss the possible solutions. Here's my take at it:
- don't fix it. State clearly that literal pathnames in source are
OS-dependent.
- keep, for each pathname constructed via #P or parse-namestring, the
string passed by the user, until the pathname is destructively modified. When dumping it, use that string if available, else warn and use a calculated string.
I still don't understand how this approach solves the problem with ASDF. Wouldn't we still have the failure on non-Windows when "\foo\bar" is passed to the #P reader? Namely, that it would be interpreted as:
{ directory: nil, name: "\foo\bar" }
What is the point of the "destructively modified" condition?
- dump-object for pathnames outputs a MAKE-PATHNAME form that
reconstructs the pathname component by component.
I was thinking about
4) Code a heuristic in the Pathname.init(String) that attempts to interpret a Pathname from the other platform by converting all '' to '/'. Add something
a) If the Pathname begins with '\' i) if win interpret as UNC server ii) non-win signal a CONDITION
b) convert all '' to '/'
c) run the rest of the current init()
On win, the init() code (line 403++) will convert the '' back to '/'.
A problem arises for non-win Pathnames that contain true '' characters in a directory/file name, which then will have no pathname<-->namestring roundtripping. It should still be possible to construct such shaggy monsters via MAKE-PATHNAME.
As for load forms, I think simply marking the namestring as "transient" (i.e. not persisting it) will do the right thing as on first access it will be re-computed to the proper local conventions.
This still doesn't completely address the presence of win-specific Pathname components (HOST with a UNC server, DEVICE with a single character string [A-Z]) in non-win. Signal a CONDITION when this is detected?
N.B. All the above written without benefit of testing with ABCL, as my wrist still precludes heavy use of Emacs.