getExportedValue(ns, name)
getNamespace(name)
getNamespaceExports(ns)
getNamespaceImports(ns)
getNamespaceName(ns)
getNamespaceUsers(ns)
getNamespaceVersion(ns)getExportedValue returns the value of the exported variable
  name in namespace ns. getNamespace returns the environment representing the name
  space name.  The namespace is loaded if necessary. getNamespaceExports returns a character vector of the names
  exported by ns. getNamespaceImports returns a representation of the imports
  used by namespace ns.  This representation is experimental
  and subject to change. getNamespaceName and getNamespaceVersion return the name
  and version of the namespace ns. getNamespaceUsers returns a character vector of the names of
  the namespaces that import namespace ns.loadNamespace for more about namespaces.