⎕CLASSES References to user-defined and external classes

The niladic system function ⎕CLASSES returns a vector of references to all the user-defined classes in the workspace, plus any references to external classes which have been retained in the workspace (typically by a call to the system function ⎕GETCLASS or the system method ⎕CLASSREF)

In this example, we have three user-defined classes in the workspace, and we also create a reference to the .Net DateTime class:

       )CLASSES
LiteraryWork    Poem    Sonnet     
      DT←'.net' ⎕NEW 'System.DateTime' 2007 5 30
      CLASSDT←DT.⎕CLASSREF
      CLASSDT
{.net:DateTime}
     ⎕CLASSES
{LiteraryWork} {Poem} {Sonnet} {.net:DateTime}