In new {quote:ClassAds}, there is no assignment operator inside an {quote:ExprTree}. A {quote:ClassAd} contains a list of attribute name and {quote:ExprTree} pairs. Any code in Condor that's directly inserting or extracting {quote:ExprTree}'s from a {quote:ClassAd} will need to be updated.
+One way to do this update in stages is to add new functions to old {quote:ClassAds} that hide the assignment operator. They would operate on the attribute name as a string and the attribute value as an {quote:ExprTree}. The internal structures could remain the same. Then, the users of the old functions could be be switched over to use the new ones. The new {quote:ClassAds} compatibility class would implement the new functions.
+
{subsubsection: ClassAdList}
There is no equivalent to the {quote:ClassAdList} class in new {quote:ClassAds}. We propose writing a compatibility {quote:ClassAdList} that's a simple wrapper around an STL vector of {quote:ClassAd} pointers. We would emulate the interface of the old {quote:ClassAdList}, but not the reference counting. Nowhere do we put the same {quote:ClassAd} into multiple {quote:ClassAdLists}.
