DuckCorp Dico

Found one definition

1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   Portable Scheme Interpreter
   PSI
      (PSI) A portable scheme interpreter by Ozan Yigit
      <oz@ursa.sis.yorku.ca>, David Keldsen and Pontus Hedman that
      includes a simple DAG compiler and a virtual machine.  It
      can be used as an integrated extension interpreter in other
      systems and allows easy addition of new primitives.  There are
      some unique debugging and tracing facilities.  Acceptable
      performance results from a fairly straight-forward
      implementation.  Continuations are fully and portably
      supported and perform well.  PSI is based on the simple
      compilers and virtual machine in Kent Dbyvig's thesis.
      The pre-release version conforms to R4RS with a number of
      useful extensions.
      (1993-02-19)