--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PageTemplates/PythonExpr.py	Fri Aug 30 08:27:34 2002 +0000
@@ -0,0 +1,82 @@
+##############################################################################
+#
+# 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
+# 
+##############################################################################
+
+"""Generic Python Expression Handler
+"""
+
+__version__='$Revision: 1.1 $'[11:-2]
+
+from TALES import CompilerError
+from string import strip, split, join, replace, lstrip
+from sys import exc_info
+
+class getSecurityManager:
+    '''Null security manager'''
+    def validate(self, *args, **kwargs):
+        return 1
+    addContext = removeContext = validateValue = validate
+
+class PythonExpr:
+    def __init__(self, name, expr, engine):
+        self.expr = expr = replace(strip(expr), '\n', ' ')
+        try:
+            d = {}
+            exec 'def f():\n return %s\n' % strip(expr) in d
+            self._f = d['f']
+        except:
+            raise CompilerError, ('Python expression error:\n'
+                                  '%s: %s') % exc_info()[:2]
+        self._get_used_names()
+
+    def _get_used_names(self):
+        self._f_varnames = vnames = []
+        for vname in self._f.func_code.co_names:
+            if vname[0] not in '$_':
+                vnames.append(vname)
+
+    def _bind_used_names(self, econtext):
+        # Bind template variables
+        names = {}
+        vars = econtext.vars
+        getType = econtext._engine.getTypes().get
+        for vname in self._f_varnames:
+            has, val = vars.has_get(vname)
+            if not has:
+                has = val = getType(vname)
+                if has:
+                    val = ExprTypeProxy(vname, val, econtext)
+            if has:
+                names[vname] = val
+        return names
+
+    def __call__(self, econtext):
+        __traceback_info__ = self.expr
+        f = self._f
+        f.func_globals.update(self._bind_used_names(econtext))        
+        return f()
+
+    def __str__(self):
+        return 'Python expression "%s"' % self.expr
+    def __repr__(self):
+        return '<PythonExpr %s>' % self.expr
+
+class ExprTypeProxy:
+    '''Class that proxies access to an expression type handler'''
+    def __init__(self, name, handler, econtext):
+        self._name = name
+        self._handler = handler
+        self._econtext = econtext
+    def __call__(self, text):
+        return self._handler(self._name, text,
+                             self._econtext._engine)(self._econtext)
+