Formulator: introduce 'structure' and 'no_translate' prefixes in TALES expression

to be able to disactivate html_escape and translation respectively

product/Formulator/TALESField.py

@@ -4,7 +4,8 @@ import Widget, Validator
 from Persistence import Persistent
 import Acquisition
 from Field import ZMIField
-from AccessControl import getSecurityManager
+from AccessControl import getSecurityManager, ClassSecurityInfo
+from copy import deepcopy
 
 class TALESWidget(Widget.TextWidget):
   default = fields.MethodField('default',
@@ -47,18 +48,55 @@ try:
     class TALESMethod(Persistent, Acquisition.Implicit):
         """A method object; calls method name in acquisition context.
         """
+        STANDARD_PREFIX_LIST = ['exists', 'nocall', 'not', 'string', 'python']
+        ADDITIONAL_PREFIX_LIST = ['structure', 'no_translate']
+        security = ClassSecurityInfo()
+
         def __init__(self, text):
             self._text = text
 
         def __call__(self, **kw):
-            expr = getattr(self, '_v_expr', None)
-            if expr is None:
-                self._v_expr = expr = getEngine().compile(self._text)
-            return getEngine().getContext(kw).evaluate(expr)
-
-            # check if we have 'View' permission for this method
-            # (raises error if not)
-            # getSecurityManager().checkPermission('View', method)
+            expression = getattr(self, '_v_expr', None)
+            if expression is None:
+              expression = self._getExpression()
+            return getEngine().getContext(kw).evaluate(expression)
+
+        def _getPrefixList(self):
+          '''
+            user should give a TALES expression as
+            prefix1; prefix2; prefixN: expression
+            prefixN should be one (and the only one) of the standard
+            zope prefixes
+          '''
+          prefix_list = []
+          # XXX can we have a path expression (so no prefix)
+          # that has ':' within?
+          splitted_text = self._text.split(':')
+          if len(splitted_text) > 1:
+            prefix_list = splitted_text[0].split(';')
+          # XXX should we assert that the prefixes are correct?
+          stripped_prefix_list = [x.strip() for x in prefix_list]
+          for prefix in stripped_prefix_list:
+            if prefix == stripped_prefix_list[-1]:
+              assert prefix in self.STANDARD_PREFIX_LIST, \
+                'prefix %s is either not found or misplaced' % prefix
+            else:
+              assert prefix in self.ADDITIONAL_PREFIX_LIST, \
+                'prefix %s is either not found or misplaced' % prefix
+          return stripped_prefix_list
+
+        def _getExpression(self):
+            expression_text = deepcopy(self._text)
+            for prefix in self.ADDITIONAL_PREFIX_LIST:
+              if prefix in self._getPrefixList():
+                expression_text = expression_text.replace(prefix + ';', '', 1)
+            expression_text = expression_text.lstrip()
+            self._v_expr = expression = getEngine().compile(expression_text)
+            return expression
+
+        security.declarePublic('hasPrefix')
+        def hasPrefix(self, prefix):
+          return prefix in self._getPrefixList()
 
     TALES_AVAILABLE = 1