o<extend_m7> sub
o2 if [#<_task> EQ 1]
 o1 if [EXISTS [#<P>]]
  (DEBUG,M7 P-word passed: #<P>)
 o1 else
  (DEBUG,M7 No P-word passed)
 o1 endif
 m7 (call built-in m7)
 (DEBUG, extend_m7 done)
o2 endif
o<extend_m7> endsub
m2
