| Word | Syntax | 
|  %! | %! comment !% | 
|  LOGIC-PRED: | LOGIC-PRED: pred | 
|  LOGIC-PREDS: | LOGIC-PREDS: preds... ; | 
|  LOGIC-VAR: | LOGIC-VAR: var | 
|  LOGIC-VARS: | LOGIC-VARS: vars... ; | 
|  !! | 
|  (<) | 
|  (=) | 
|  (=<) | 
|  (==) | 
|  (>) | 
|  (>=) | 
|  (\=) | 
|  (\==) | 
|  ;; | 
|  \+ | 
|  __ | 
|  appendo | 
|  failo | 
|  lengtho | 
|  listo | 
|  membero | 
|  nlo | 
|  nonvaro | 
|  trueo | 
|  varo | 
|  writenlo | 
|  writeo | 
| Word | Stack effect | 
|  =:= | ( quot: ( env -- n m ) -- goal ) | 
|  =\= | ( quot: ( env -- n m ) -- goal ) | 
|  callback | ( head quot: ( callback-env -- ? ) -- ) | 
|  callbacks | ( defs -- ) | 
|  clear-pred | ( pred -- ) | 
|  fact | ( head -- ) | 
|  fact* | ( head -- ) | 
|  facts | ( defs -- ) | 
|  invoke | ( quot: ( env -- ) -- goal ) | 
|  invoke* | ( quot: ( env -- ? ) -- goal ) | 
|  is | ( quot: ( env -- value ) dist -- goal ) | 
|  notrace | ( -- ) | 
|  nquery | ( goal-def/defs n/f -- bindings-array/success? ) | 
|  query | ( goal-def/defs -- bindings-array/success? ) | 
|  retract | ( head-def -- ) | 
|  retract-all | ( head-def -- ) | 
|  rule | ( head body -- ) | 
|  rule* | ( head body -- ) | 
|  rules | ( defs -- ) | 
|  trace | ( -- ) | 
|  unify | ( cb-env x y -- success? ) | 
| Vocabulary | Summary | 
|  logic.examples |