1 files changed, 74 insertions, 0 deletions
diff --git a/lib/kross/python/scripts/RestrictedPython/MutatingWalker.py b/lib/kross/python/scripts/RestrictedPython/MutatingWalker.py
new file mode 100644
index 00000000..b0b8c9ce
--- /dev/null
+++ b/lib/kross/python/scripts/RestrictedPython/MutatingWalker.py
@@ -0,0 +1,74 @@
+##############################################################################
+#
+# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+
+__version__='$Revision: 1.6 $'[11:-2]
+
+from SelectCompiler import ast
+
+ListType = type([])
+TupleType = type(())
+SequenceTypes = (ListType, TupleType)
+
+class MutatingWalker:
+
+    def __init__(self, visitor):
+        self.visitor = visitor
+        self._cache = {}
+
+    def defaultVisitNode(self, node, walker=None, exclude=None):
+        for name, child in node.__dict__.items():
+            if exclude is not None and name in exclude:
+                continue
+            v = self.dispatchObject(child)
+            if v is not child:
+                # Replace the node.
+                node.__dict__[name] = v
+        return node
+
+    def visitSequence(self, seq):
+        res = seq
+        for idx in range(len(seq)):
+            child = seq[idx]
+            v = self.dispatchObject(child)
+            if v is not child:
+                # Change the sequence.
+                if type(res) is ListType:
+                    res[idx : idx + 1] = [v]
+                else:
+                    res = res[:idx] + (v,) + res[idx + 1:]
+        return res
+
+    def dispatchObject(self, ob):
+        '''
+        Expected to return either ob or something that will take
+        its place.
+        '''
+        if isinstance(ob, ast.Node):
+            return self.dispatchNode(ob)
+        elif type(ob) in SequenceTypes:
+            return self.visitSequence(ob)
+        else:
+            return ob
+
+    def dispatchNode(self, node):
+        klass = node.__class__
+        meth = self._cache.get(klass, None)
+        if meth is None:
+            className = klass.__name__
+            meth = getattr(self.visitor, 'visit' + className,
+                           self.defaultVisitNode)
+            self._cache[klass] = meth
+        return meth(node, self)
+
+def walk(tree, visitor):
+    return MutatingWalker(visitor).dispatchNode(tree)