The VSI Text Processing Utility (TPU) provides a structured
  progamming language with an interpreter, compiler, and other software
  components, for creating text editors and other applications.  TPU
  has a callable interface so you can call editing functions from a
  program written in BLISS, C, FORTRAN, or other language.

  EVE (Extensible Versatile Editor) is the default TPU application.
  You can use TPU to customize EVE or to create your own
  applications.  The EVE source files are available online as examples
  of TPU programming and as a kind of run-time library of TPU
  procedures.  For a list of the EVE source files, use the following
  DCL command:

     $ DIRECTORY SYS$EXAMPLES:EVE$*.TPU