This is a running (mocka 9905, linux and TopSpeed 3.10, DOS) version of the
PL/0 compiler from the book

  Wirth, Niklaus:
  Compilerbau: Eine Einführung.
  4. durchges. Aufl. - Stuttgard: Teubner, 1986.
  (LAMM Bd. 36) (Teubner-Studienbücher: Informatik)
  ISBN 3-519-32338-9

With respect to the original code (see directory orig), I tried to only
change things which are not compatible with my environment. But at some
points I couldn't withstand... sorry.

2010-04-05 solyga@beast