[Zope-Checkins] CVS: Zope3/lib/python/Zope/App/Traversing - Traverser.py:1.1.2.7

[Shane Hathaway]

Update of /cvs-repository/Zope3/lib/python/Zope/App/Traversing
In directory cvs.zope.org:/tmp/cvs-serv16296

Modified Files:
      Tag: Zope-3x-branch
	Traverser.py 
Log Message:
- Report a better exception when no ITraversable is available.

- Updated license and restored whitespace.  Code needs room to breathe. :-)



=== Zope3/lib/python/Zope/App/Traversing/Traverser.py 1.1.2.6 => 1.1.2.7 ===
+# Copyright (c) 2001, 2002 Zope Corporation and Contributors.
+# All Rights Reserved.
 # 
 # This software is subject to the provisions of the Zope Public License,
 # Version 1.1 (ZPL).  A copy of the ZPL should accompany this distribution.
@@ -6,6 +7,10 @@
 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS 
 # FOR A PARTICULAR PURPOSE.
+"""Default implementation of ITraverser.
+
+$Id$
+"""
 
 from ITraverser import ITraverser
 from ITraversable import ITraversable
@@ -25,7 +30,7 @@
         yield w
         w = wrapper.getcontext(w)
 
-_marker = []
+_marker = object()
 
 class Traverser:
     """Provide traverse features"""
@@ -41,7 +46,8 @@
 
     def getPhysicalRoot(self):
         # Loop over all wrappers until the last one, which is the root.
-        for w in WrapperChain(self._wrapper): pass
+        for w in WrapperChain(self._wrapper):
+            pass
         return w
 
     def getPhysicalPath(self):
@@ -49,12 +55,14 @@
         
         for w in WrapperChain(self._wrapper):
             d = wrapper.getdict(w)
-            if d: path.insert(0, d['name'])
+            if d:
+                path.insert(0, d['name'])
 
         return tuple(path)
     
     def unrestrictedTraverse(self, path, default=_marker, restricted=0):
-        if not path: return self._wrapper
+        if not path:
+            return self._wrapper
 
         if isinstance(path, StringTypes):
             path = path.split('/')
@@ -74,7 +82,8 @@
             # Start at the root
             pop()
             curr = self.getPhysicalRoot()
-            if restricted: validate(None, curr)
+            if restricted:
+                validate(None, curr)
 
         try:
             while path:
@@ -85,23 +94,24 @@
 
                 if name == '..':
                     curr = wrapper.getcontext(curr) or curr
-                    if restricted: validate(None, curr)
+                    if restricted:
+                        validate(None, curr)
                     continue
 
                 traversable = getAdapter(curr, ITraversable, None)
                 if traversable is None:
-                    # Cannot be traversed, so we cannot find the next name
-                    raise NotFoundError, name
+                    raise NotFoundError, 'No traversable adapter found'
 
-                else:
-                    next = traversable.traverse(name, path)
-                    curr = wrapper.Wrapper(next, curr, name=name)
-                    if restricted: validate(name, curr)
+                next = traversable.traverse(name, path)
+                curr = wrapper.Wrapper(next, curr, name=name)
+                if restricted:
+                    validate(name, curr)
 
             return curr
 
         except:
-            if default == _marker: raise
+            if default == _marker:
+                raise
             return default
 
     def restrictedTraverse(self, path, default=_marker):