[gen] More methods on AbstractWrapper.

fields/ref.py

@@ -1022,12 +1022,18 @@ class Ref(Field):
             res = refObject.tool.o.truncateValue(res, maxWidth)
         return res
 
-    def getIndexOf(self, obj, tiedUid):
+    def getIndexOf(self, obj, tiedUid, raiseError=True):
         '''Gets the position of tied object identified by p_tiedUid within this
            field on p_obj.'''
         uids = getattr(obj.aq_base, self.name, None)
-        if not uids: raise IndexError()
+        if not uids:
+            if raiseError: raise IndexError()
+            else: return
+        if tiedUid in uids:
             return uids.index(tiedUid)
+        else:
+            if raiseError: raise IndexError()
+            else: return
 
     def sort(self, obj):
         '''Called when the user wants to sort the content of this field.'''

gen/wrappers/__init__.py

@@ -1083,4 +1083,14 @@ class AbstractWrapper(object):
            p_name.'''
         v = getattr(self, name)
         if v: return v.getFilePath(self)
+
+    def getIndexOf(self, name, obj):
+        '''Returns, as an integer starting at 0, the position of p_obj within
+           objects linked to p_self via field p_name.'''
+        o = self.o
+        return o.getAppyType(name).getIndexOf(o, obj.uid)
+
+    def allows(self, permission, raiseError=False):
+        '''Check doc @Mixin.allows.'''
+        return self.o.allows(permission, raiseError=raiseError)
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