Index: ntpath.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/ntpath.py,v
retrieving revision 1.63
diff -c -r1.63 ntpath.py
*** ntpath.py	22 Aug 2005 18:01:03 -0000	1.63
--- ntpath.py	27 Oct 2005 17:15:30 -0000
***************
*** 14,20 ****
             "getatime","getctime", "islink","exists","lexists","isdir","isfile",
             "ismount","walk","expanduser","expandvars","normpath","abspath",
             "splitunc","curdir","pardir","sep","pathsep","defpath","altsep",
!            "extsep","devnull","realpath","supports_unicode_filenames"]
  
  # strings representing various path-related bits and pieces
  curdir = '.'
--- 14,20 ----
             "getatime","getctime", "islink","exists","lexists","isdir","isfile",
             "ismount","walk","expanduser","expandvars","normpath","abspath",
             "splitunc","curdir","pardir","sep","pathsep","defpath","altsep",
!            "extsep","devnull","realpath","supports_unicode_filenames","relpath"]
  
  # strings representing various path-related bits and pieces
  curdir = '.'
***************
*** 508,510 ****
--- 508,536 ----
  # Win9x family and earlier have no Unicode filename support.
  supports_unicode_filenames = (hasattr(sys, "getwindowsversion") and
                                sys.getwindowsversion()[3] >= 2)
+ 
+ def relpath(path, start=curdir):
+     """Return a relative version of a path"""
+ 
+     if not path:
+         raise ValueError, 'no path specified'    
+     start_list = (abspath(start)).split(sep)
+     path_list = (abspath(path)).split(sep)
+     if start_list[0].lower() <> path_list[0].lower():
+         unc_path, rest = splitunc(path)
+         unc_start, rest = splitunc(start)
+         if (unc_path and not unc_start) or (not unc_path and unc_start):
+             raise ValueError, "Cannot mix UNC and non-UNC paths (%s and %s)" \
+                                                                  % (path, start)
+         else:
+             raise ValueError, 'path is on drive %s, start on drive %s' \
+                                                  % (path_list[0], start_list[0])
+     # Work out how much of the filepath is shared by start and path.
+     for i in range(min(len(start_list), len(path_list))):
+         if start_list[i].lower() <> path_list[i].lower():
+             break
+     else:
+         i+=1
+ 
+     rel_list = [pardir] * (len(start_list)-i) + path_list[i:]
+     return os.path.join(*rel_list)
Index: posixpath.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/posixpath.py,v
retrieving revision 1.75
diff -c -r1.75 posixpath.py
*** posixpath.py	22 Aug 2005 18:01:03 -0000	1.75
--- posixpath.py	27 Oct 2005 17:15:31 -0000
***************
*** 19,25 ****
             "ismount","walk","expanduser","expandvars","normpath","abspath",
             "samefile","sameopenfile","samestat",
             "curdir","pardir","sep","pathsep","defpath","altsep","extsep",
!            "devnull","realpath","supports_unicode_filenames"]
  
  # strings representing various path-related bits and pieces
  curdir = '.'
--- 19,25 ----
             "ismount","walk","expanduser","expandvars","normpath","abspath",
             "samefile","sameopenfile","samestat",
             "curdir","pardir","sep","pathsep","defpath","altsep","extsep",
!            "devnull","realpath","supports_unicode_filenames","relpath"]
  
  # strings representing various path-related bits and pieces
  curdir = '.'
***************
*** 452,454 ****
--- 452,473 ----
      return path
  
  supports_unicode_filenames = False
+ 
+ def relpath(path, start=curdir):
+     """Return a relative version of a path"""
+ 
+     if not path:
+         raise ValueError, 'no path specified'
+     
+     start_list = (abspath(start)).split(sep)
+     path_list = (abspath(path)).split(sep)
+  
+     # Work out how much of the filepath is shared by start and path.
+     for i in range(min(len(start_list), len(path_list))):
+         if start_list[i] <> path_list[i]:
+             break
+     else:
+         i+=1
+ 
+     rel_list = [pardir] * (len(start_list)-i) + path_list[i:]
+     return os.path.join(*rel_list)
Index: test/test_ntpath.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_ntpath.py,v
retrieving revision 1.19
diff -c -r1.19 test_ntpath.py
*** test/test_ntpath.py	10 Jul 2004 20:42:22 -0000	1.19
--- test/test_ntpath.py	27 Oct 2005 17:15:33 -0000
***************
*** 127,132 ****
--- 127,142 ----
  else:
      tester('ntpath.abspath("C:\\")', "C:\\")
  
+ currentdir = os.path.split(os.getcwd())[-1]
+ tester('ntpath.relpath("a")', 'a')
+ tester('ntpath.relpath(os.path.abspath("a"))', 'a')
+ tester('ntpath.relpath("a/b")', 'a\\b')
+ tester('ntpath.relpath("../a/b")', '..\\a\\b')
+ tester('ntpath.relpath("a", "../b")', '..\\'+currentdir+'\\a')
+ tester('ntpath.relpath("a/b", "../c")', '..\\'+currentdir+'\\a\\b')
+ tester('ntpath.relpath("a", "b/c")', '..\\..\\a')
+ tester('ntpath.relpath("//conky/mountpoint/a", "//conky/mountpoint/b/c")', '..\\..\\a')
+ 
  if errors:
      raise TestFailed(str(errors) + " errors.")
  elif verbose:
Index: test/test_posixpath.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_posixpath.py,v
retrieving revision 1.14
diff -c -r1.14 test_posixpath.py
*** test/test_posixpath.py	3 Jun 2005 22:40:28 -0000	1.14
--- test/test_posixpath.py	27 Oct 2005 17:15:34 -0000
***************
*** 2,8 ****
  from test import test_support
  
  import posixpath, os
! from posixpath import realpath, abspath, join, dirname, basename
  
  # An absolute path to a temporary filename for testing. We can't rely on TESTFN
  # being an absolute path, so we need this.
--- 2,8 ----
  from test import test_support
  
  import posixpath, os
! from posixpath import realpath, abspath, join, dirname, basename, relpath
  
  # An absolute path to a temporary filename for testing. We can't rely on TESTFN
  # being an absolute path, so we need this.
***************
*** 508,513 ****
--- 508,524 ----
          def safe_rmdir(self, dirname):
              self.pass_os_error(os.rmdir, dirname)
  
+     def test_relpath(self):
+         currentdir = os.path.split(os.getcwd())[-1]
+         self.assertRaises(ValueError, posixpath.relpath, "")
+         self.assertEqual(posixpath.relpath("a"), "a")
+         self.assertEqual(posixpath.relpath(os.path.abspath("a")), "a")
+         self.assertEqual(posixpath.relpath("a/b"), "a/b")
+         self.assertEqual(posixpath.relpath("../a/b"), "../a/b")
+         self.assertEqual(posixpath.relpath("a", "../b"), "../"+currentdir+"/a")
+         self.assertEqual(posixpath.relpath("a/b", "../c"), "../"+currentdir+"/a/b")
+         self.assertEqual(posixpath.relpath("a", "b/c"), "../../a")
+ 
  def test_main():
      test_support.run_unittest(PosixPathTest)