anchor.diff:  
   variable '.error!  ( u -- u )
   \g Execution vector for setting error source
  -
  -variable 'compile,  ( -- a-addr )
  -\g Execution vector for compile,
   
   defer interpret  ( -- a-addr )
   
  
positive.code:    xtof (interpret) (is) interpret
     xtof .err '.error !
     xtof noop '.error! !
     xtof , 'compile, !
     xtof noop (is) .prompt
     xtof (refill) 'refill !
     xtof forth-wordlist colname 3 cells - to forth-wordlist 
  
negative.code:    tib dup [ /tib ] literal accept sourcevar 2! >in off -1 ;  
  
  \g @see anscore
  defer compile,  ( xt -- )
  
  \g Compile inline xt into current colon def
  : (compile)  ( -- ) 
  