Are you referring to the DBMS_XSLPROCESSOR Oracle’s package ?
If so, I think you should explain what you need to achieve without assuming that the SQL Server experts who know how to process XML documents in SQL Server also know how to do it in Oracle and know the ValueOf procedure/function.
What does this function do? Is it a native function? I couldn’t find anything called valueof() via Google.
There is an Oracle Package named DBMS_XSLPROCESSOR, which “provides an interface to manage the contents and structure of XML documents”.
The VALUEOF Function and Procedure “retrieves the value of the first node from the tree that matches the given pattern”.
There is no other ValueOf function or procedure in Oracle, but I’m not sure if that is what the OP meant. It could be a totally different thing. In Java, for example, it is a type conversion method.