the included bcl provides classes for collections, reflection, regular expressions, string handling and data access. it also supports linq, with full support for linq to objects and expression trees. almost all of the codice_10 and codice_11 namespaces are exposed. it also supports serialization of objects, for data persistence. silverlight can handle data in rss or json format, in addition to xml. the bcl provides enhanced support for working with xml data, including the codice_12 and codice_13 classes. silverlight 2 also supports asynchronous programming via the use of the threading libraries.