VMS Help PASCAL, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  file-spec[,...]

  Specifies one or more Compaq Pascal source files to be compiled.
  If you do not specify a file type for an input file, the default
  file type PAS is used.

  You can specify more than one input file.  If you  separate  the
  file  specifications  with  commas  (,),  each  file is compiled
  separately.  If you separate the file specifications  with  plus
  signs  (+),  the files are concatenated and compiled as a single
  input file, producing single object and listing files.   If  you
  specify SYS$INPUT as the file-spec parameter, the source program
  must follow the command in the input stream.