anchor.diff:                  compiling if ( n word ) 
                       char getattr(vm,"{}")["{}"]=pop() 
                       :> format(tos().vid,pop().name) ( n s ) 
  -                    dup comment , compyle , ( n ) \ n has already been compiled as a literal
  +                    compyle , ( n ) \ n has already been compiled as a literal
                   else ( n word )
                       py: getattr(vm,tos().vid)[pop().name]=pop(1)
                   then ; immediate
  
positive.code:     BL word (create) 
  <py> 
  last().type = "constant";
  source = 'push(getattr(vm,"{}")["{}"])'.format(current, last().name)
  last().xt = compile(source,"","exec");
  if not getattr(vm,current,False): setattr(vm,current,{})
  exec('getattr(vm,"{}")["{}"]=pop()'.format(current, last().name))
  </py> reveal ; 
  
negative.code: [] value [all-pass]      ( private ) // ( -- ["words"] ) array of words for all-pass in selftest
  : ***           ( <description> -- ) // Start a selftest section
                  CR word trim ( desc )
                  s" *** {} ... " :> format(pop()) to description
                  depth if 
                      description . ." aborted" cr 
  