Some minute changes.

Lib/os.py

@@ -1,4 +1,4 @@
-# os.py -- either mac or posix depending on what system we're on.
+# os.py -- either mac, dos or posix depending on what system we're on.
 
 # This exports:
 # - all functions from either posix or mac, e.g., os.unlink, os.stat, etc.
@@ -14,7 +14,7 @@
 # and opendir), and leave all pathname manipulation to os.path
 # (e.g., split and join).
 
-# XXX This will need to distinguish between real posix and MS-DOS emulation
+# XXX This is incorrect if the import *path fails...
 
 try:
 	from posix import *
@@ -30,14 +30,24 @@ try:
 	path = posixpath
 	del posixpath
 except ImportError:
-	from mac import *
-	name = 'mac'
-	curdir = ':'
-	pardir = '::'
-	sep = ':'
-	import macpath
-	path = macpath
-	del macpath
+	try:
+		from mac import *
+		name = 'mac'
+		curdir = ':'
+		pardir = '::'
+		sep = ':'
+		import macpath
+		path = macpath
+		del macpath
+	except ImportError:
+		from dos import *
+		name = 'dos'
+		curdir = '.'		# XXX doesn't always work
+		pardir = '..'		# XXX doesn't always work
+		sep = '/'		# XXX or '\\' ???
+		import dospath
+		path = dospath
+		del dospath
 
 def execl(file, *args):
 	execv(file, args)