Two in one day! My fourth VAX Professional article was about the callable TPU interface. TPU stands for Text Processing Utility, and it was a language introduced in VAX/VMS V4.2 for writing editors. The EVE editor was written in TPU, and it was easy to extend or modify EVE by writing new TPU routines or modifying the existing routines. My FLIST program was also written in TPU (and C).
In addition to describing the callable interface, I provided a MACRO module that provided a simplified callable TPU interface. The article describes why I did that.