src/HOL/Tools/res_clause.ML
author mengj
Wed Dec 14 01:40:43 2005 +0100 (2005-12-14)
changeset 18402 aaba095cf62b
parent 18390 aaecdaef4c04
child 18403 df0c0f35c897
permissions -rw-r--r--
1. changed fol_type, it's not a string type anymore.
2. sort literals in clauses.
     1 (*  Author: Jia Meng, Cambridge University Computer Laboratory
     2 
     3     ID: $Id$
     4     Copyright 2004 University of Cambridge
     5 
     6 ML data structure for storing/printing FOL clauses and arity clauses.
     7 Typed equality is treated differently.
     8 *)
     9 
    10 (* works for writeoutclasimp on typed *)
    11 signature RES_CLAUSE =
    12   sig
    13   val keep_types : bool ref
    14   val special_equal : bool ref
    15   val tagged : bool ref
    16 
    17   exception ARCLAUSE of string
    18   exception CLAUSE of string * term
    19   type arityClause 
    20   type classrelClause
    21   type clause
    22   val init : theory -> unit
    23   val make_axiom_clause : Term.term -> string * int -> clause
    24   val make_conjecture_clauses : term list -> clause list
    25   val get_axiomName : clause ->  string
    26   val isTaut : clause -> bool
    27   val num_of_clauses : clause -> int
    28 
    29   val clause2dfg : clause -> string * string list
    30   val clauses2dfg : clause list -> string -> clause list -> clause list ->
    31 	   (string * int) list -> (string * int) list -> string
    32   val tfree_dfg_clause : string -> string
    33 
    34   val arity_clause_thy: theory -> arityClause list 
    35   val classrel_clauses_thy: theory -> classrelClause list 
    36 
    37   val tptp_arity_clause : arityClause -> string
    38   val tptp_classrelClause : classrelClause -> string
    39   val tptp_clause : clause -> string list
    40   val clause2tptp : clause -> string * string list
    41   val tfree_clause : string -> string
    42   val schematic_var_prefix : string
    43   val fixed_var_prefix : string
    44   val tvar_prefix : string
    45   val tfree_prefix : string
    46   val clause_prefix : string 
    47   val arclause_prefix : string
    48   val const_prefix : string
    49   val tconst_prefix : string 
    50   val class_prefix : string 
    51 
    52   val union_all : ''a list list -> ''a list
    53   val ascii_of : String.string -> String.string
    54   val paren_pack : string list -> string
    55   val bracket_pack : string list -> string
    56   val make_schematic_var : String.string * int -> string
    57   val make_fixed_var : String.string -> string
    58   val make_schematic_type_var : string * int -> string
    59   val make_fixed_type_var : string -> string
    60   val make_fixed_const : String.string -> string		
    61   val make_fixed_type_const : String.string -> string   
    62   val make_type_class : String.string -> string
    63   val isMeta : String.string -> bool
    64   
    65   type typ_var
    66   val mk_typ_var_sort : Term.typ -> typ_var * sort
    67   type type_literal
    68   val add_typs_aux2 : (typ_var * string list) list -> type_literal list * type_literal list
    69   val gen_tptp_cls : int * string * string * string -> string
    70   val gen_tptp_type_cls : int * string * string * string * int -> string
    71   val tptp_of_typeLit : type_literal -> string
    72 
    73   end;
    74 
    75 structure ResClause: RES_CLAUSE =
    76 struct
    77 
    78 (* Added for typed equality *)
    79 val special_equal = ref false; (* by default,equality does not carry type information *)
    80 val eq_typ_wrapper = "typeinfo"; (* default string *)
    81 
    82 
    83 val schematic_var_prefix = "V_";
    84 val fixed_var_prefix = "v_";
    85 
    86 val tvar_prefix = "T_";
    87 val tfree_prefix = "t_";
    88 
    89 val clause_prefix = "cls_"; 
    90 val arclause_prefix = "clsarity_" 
    91 val clrelclause_prefix = "clsrel_";
    92 
    93 val const_prefix = "c_";
    94 val tconst_prefix = "tc_"; 
    95 
    96 val class_prefix = "class_"; 
    97 
    98 
    99 fun union_all xss = foldl (op union) [] xss;
   100 
   101  
   102 (*Provide readable names for the more common symbolic functions*)
   103 val const_trans_table =
   104       Symtab.make [("op =", "equal"),
   105 	  	   ("op <=", "lessequals"),
   106 		   ("op <", "less"),
   107 		   ("op &", "and"),
   108 		   ("op |", "or"),
   109 		   ("op +", "plus"),
   110 		   ("op -", "minus"),
   111 		   ("op *", "times"),
   112 		   ("op -->", "implies"),
   113 		   ("{}", "emptyset"),
   114 		   ("op :", "in"),
   115 		   ("op Un", "union"),
   116 		   ("op Int", "inter"),
   117 		   ("List.op @", "append")];
   118 
   119 val type_const_trans_table =
   120       Symtab.make [("*", "t_prod"),
   121 	  	   ("+", "t_sum"),
   122 		   ("~=>", "t_map")];
   123 
   124 (*Escaping of special characters.
   125   Alphanumeric characters are left unchanged.
   126   The character _ goes to __
   127   Characters in the range ASCII space to / go to _A to _P, respectively.
   128   Other printing characters go to _NNN where NNN is the decimal ASCII code.*)
   129 local
   130 
   131 val A_minus_space = Char.ord #"A" - Char.ord #" ";
   132 
   133 fun ascii_of_c c =
   134   if Char.isAlphaNum c then String.str c
   135   else if c = #"_" then "__"
   136   else if #" " <= c andalso c <= #"/" 
   137        then "_" ^ String.str (Char.chr (Char.ord c + A_minus_space))
   138   else if Char.isPrint c then ("_" ^ Int.toString (Char.ord c))
   139   else ""
   140 
   141 in
   142 
   143 val ascii_of = String.translate ascii_of_c;
   144 
   145 end;
   146 
   147 (* convert a list of strings into one single string; surrounded by brackets *)
   148 fun paren_pack [] = ""   (*empty argument list*)
   149   | paren_pack strings = "(" ^ commas strings ^ ")";
   150 
   151 fun bracket_pack strings = "[" ^ commas strings ^ "]";
   152 
   153 
   154 (*Remove the initial ' character from a type variable, if it is present*)
   155 fun trim_type_var s =
   156   if s <> "" andalso String.sub(s,0) = #"'" then String.extract(s,1,NONE)
   157   else error ("trim_type: Malformed type variable encountered: " ^ s);
   158 
   159 fun ascii_of_indexname (v,0) = ascii_of v
   160   | ascii_of_indexname (v,i) = ascii_of v ^ "_" ^ Int.toString i;
   161 
   162 fun make_schematic_var v = schematic_var_prefix ^ (ascii_of_indexname v);
   163 fun make_fixed_var x = fixed_var_prefix ^ (ascii_of x);
   164 
   165 fun make_schematic_type_var (x,i) = 
   166       tvar_prefix ^ (ascii_of_indexname (trim_type_var x,i));
   167 fun make_fixed_type_var x = tfree_prefix ^ (ascii_of (trim_type_var x));
   168 
   169 fun make_fixed_const c =
   170     case Symtab.lookup const_trans_table c of
   171         SOME c' => c'
   172       | NONE =>  const_prefix ^ ascii_of c;
   173 
   174 fun make_fixed_type_const c = 
   175     case Symtab.lookup type_const_trans_table c of
   176         SOME c' => c'
   177       | NONE =>  tconst_prefix ^ ascii_of c;
   178 
   179 fun make_type_class clas = class_prefix ^ ascii_of clas;
   180 
   181 
   182 
   183 (***** definitions and functions for FOL clauses, prepared for conversion into TPTP format or SPASS format. *****)
   184 
   185 val keep_types = ref true;
   186 
   187 datatype kind = Axiom | Hypothesis | Conjecture;
   188 fun name_of_kind Axiom = "axiom"
   189   | name_of_kind Hypothesis = "hypothesis"
   190   | name_of_kind Conjecture = "conjecture";
   191 
   192 type clause_id = int;
   193 type axiom_name = string;
   194 
   195 
   196 type polarity = bool;
   197 
   198 type indexname = Term.indexname;
   199 
   200 
   201 (* "tag" is used for vampire specific syntax  *)
   202 type tag = bool; 
   203 
   204 
   205 (**** Isabelle FOL clauses ****)
   206 
   207 val tagged = ref false;
   208 
   209 type pred_name = string;
   210 type sort = Term.sort;
   211 
   212 
   213 
   214 datatype typ_var = FOLTVar of indexname | FOLTFree of string;
   215 
   216 datatype fol_type = AtomV of string
   217 		  | AtomF of string
   218 		  | Comp of string * fol_type list;
   219 
   220 fun string_of_fol_type (AtomV x) = x
   221   | string_of_fol_type (AtomF x) = x
   222   | string_of_fol_type (Comp(tcon,tps)) = 
   223     let val tstrs = map string_of_fol_type tps
   224     in
   225 	tcon ^ (paren_pack tstrs)
   226     end;
   227 
   228 
   229 datatype type_literal = LTVar of string | LTFree of string;
   230 
   231 datatype folTerm = UVar of string * fol_type
   232                  | Fun of string * fol_type list * folTerm list;
   233 datatype predicate = Predicate of pred_name * fol_type list * folTerm list;
   234 
   235 datatype literal = Literal of polarity * predicate * tag;
   236 
   237 fun mk_typ_var_sort (TFree(a,s)) = (FOLTFree a,s)
   238   | mk_typ_var_sort (TVar(v,s)) = (FOLTVar v,s);
   239 
   240 
   241 
   242 (* ML datatype used to repsent one single clause: disjunction of literals. *)
   243 datatype clause = 
   244 	 Clause of {clause_id: clause_id,
   245 		    axiom_name: axiom_name,
   246 		    kind: kind,
   247 		    literals: literal list,
   248 		    types_sorts: (typ_var * sort) list, 
   249                     tvar_type_literals: type_literal list, 
   250                     tfree_type_literals: type_literal list ,
   251                     tvars: string list,
   252                     predicates: (string*int) list,
   253                     functions: (string*int) list};
   254 
   255 
   256 exception CLAUSE of string * term;
   257 
   258 fun get_literals (c as Clause(cls)) = #literals cls;
   259 
   260 fun components_of_literal (Literal (pol,pred,tag)) = ((pol,pred),tag);
   261 
   262 fun predicate_name (Predicate(predname,_,_)) = predname;
   263 
   264 
   265 (*** make clauses ***)
   266 
   267 fun isFalse (Literal (pol,Predicate(a,_,[]),_)) =
   268       (pol andalso a = "c_False") orelse
   269       (not pol andalso a = "c_True")
   270   | isFalse _ = false;
   271 
   272 fun isTrue (Literal (pol,Predicate(a,_,[]),_)) =
   273       (pol andalso a = "c_True") orelse
   274       (not pol andalso a = "c_False")
   275   | isTrue _ = false;
   276   
   277 fun isTaut (Clause {literals,...}) = exists isTrue literals;  
   278 
   279 fun make_clause (clause_id,axiom_name,kind,literals,
   280                  types_sorts,tvar_type_literals,
   281                  tfree_type_literals,tvars, predicates, functions) =
   282   if forall isFalse literals 
   283   then error "Problem too trivial for resolution (empty clause)"
   284   else
   285      Clause {clause_id = clause_id, axiom_name = axiom_name, kind = kind, 
   286              literals = literals, types_sorts = types_sorts,
   287              tvar_type_literals = tvar_type_literals,
   288              tfree_type_literals = tfree_type_literals,
   289              tvars = tvars, predicates = predicates, 
   290              functions = functions};
   291 
   292 
   293 (** Some Clause destructor functions **)
   294 
   295 fun string_of_kind (Clause cls) = name_of_kind (#kind cls);
   296 
   297 fun get_axiomName (Clause cls) = #axiom_name cls;
   298 
   299 fun get_clause_id (Clause cls) = #clause_id cls;
   300 
   301 fun funcs_of_cls (Clause cls) = #functions cls;
   302 
   303 fun preds_of_cls (Clause cls) = #predicates cls;
   304 
   305 
   306 (*Declarations of the current theory--to allow suppressing types.*)
   307 val const_typargs = ref (Library.K [] : (string*typ -> typ list));
   308 
   309 fun num_typargs(s,T) = if !keep_types then length (!const_typargs (s,T)) else 0;
   310 
   311 (*Initialize the type suppression mechanism with the current theory before
   312     producing any clauses!*)
   313 fun init thy = (const_typargs := Sign.const_typargs thy);
   314     
   315 
   316 (*Flatten a type to a fol_type while accumulating sort constraints on the TFrees and
   317   TVars it contains.*)    
   318 fun type_of (Type (a, Ts)) = 
   319       let val (folTyps, (ts, funcs)) = types_of Ts 
   320 	  val t = make_fixed_type_const a
   321       in    
   322 	  (Comp(t,folTyps), (ts, (t, length Ts)::funcs))
   323       end
   324   | type_of (TFree (a,s)) = 
   325       let val t = make_fixed_type_var a
   326       in (AtomF(t), ([((FOLTFree a),s)], [(t,0)])) end
   327   | type_of (TVar (v, s)) = (AtomV(make_schematic_type_var v), ([((FOLTVar v),s)], []))
   328 and types_of Ts =
   329       let val foltyps_ts = map type_of Ts 
   330 	  val (folTyps,ts_funcs) = ListPair.unzip foltyps_ts
   331 	  val (ts, funcslist) = ListPair.unzip ts_funcs
   332       in    
   333 	  (folTyps, (union_all ts, union_all funcslist))
   334       end;
   335 
   336 
   337 fun const_types_of (c,T) = types_of (!const_typargs (c,T));
   338 
   339 (* Any variables created via the METAHYPS tactical should be treated as
   340    universal vars, although it is represented as "Free(...)" by Isabelle *)
   341 val isMeta = String.isPrefix "METAHYP1_"
   342 
   343 fun pred_name_type (Const(c,T)) = 
   344       let val (contys,(folTyps,funcs)) = const_types_of (c,T)
   345       in (make_fixed_const c, (contys,folTyps), funcs) end
   346   | pred_name_type (Free(x,T))  = 
   347       if isMeta x then raise CLAUSE("Predicate Not First Order 1", Free(x,T)) 
   348       else (make_fixed_var x, ([],[]), [])
   349   | pred_name_type (v as Var _) = raise CLAUSE("Predicate Not First Order 2", v)
   350   | pred_name_type t        = raise CLAUSE("Predicate input unexpected", t);
   351 
   352 
   353 (* For typed equality *)
   354 (* here "arg_typ" is the type of "="'s argument's type, not the type of the equality *)
   355 (* Find type of equality arg *)
   356 fun eq_arg_type (Type("fun",[T,_])) = 
   357     let val (folT,_) = type_of T;
   358     in  folT  end;
   359 
   360 fun fun_name_type (Const("op =",T)) args =   (*FIXME: Is this special treatment of = needed??*)
   361       let val t = make_fixed_const "op ="
   362       in (t, ([eq_arg_type T], []), [(t,2)]) end
   363   | fun_name_type (Const(c,T)) args = 
   364       let val t = make_fixed_const c
   365 	  val (contys, (folTyps,funcs)) = const_types_of (c,T)
   366 	  val arity = num_typargs(c,T) + length args
   367       in
   368 	  (t, (contys,folTyps), ((t,arity)::funcs))
   369       end
   370  | fun_name_type (Free(x,T)) args  = 
   371       let val t = make_fixed_var x
   372       in  (t, ([],[]), [(t, length args)]) end
   373   | fun_name_type f args = raise CLAUSE("Function Not First Order 1", f);
   374 
   375 
   376 fun term_of (Var(ind_nm,T)) = 
   377       let val (folType,(ts,funcs)) = type_of T
   378       in
   379 	  (UVar(make_schematic_var ind_nm, folType), (ts, funcs))
   380       end
   381   | term_of (Free(x,T)) = 
   382       let val (folType, (ts,funcs)) = type_of T
   383       in
   384 	  if isMeta x then (UVar(make_schematic_var(x,0),folType),
   385 			    (ts, ((make_schematic_var(x,0)),0)::funcs))
   386 	  else
   387 	      (Fun(make_fixed_var x, [folType], []), 
   388 	       (ts, ((make_fixed_var x),0)::funcs))
   389       end
   390   | term_of (Const(c,T)) =  (* impossible to be equality *)
   391       let val (contys, (folTyps,funcs)) = const_types_of (c,T)
   392       in
   393 	  (Fun(make_fixed_const c, contys, []),
   394 	   (folTyps, ((make_fixed_const c),0)::funcs))
   395       end    
   396   | term_of app = 
   397       let val (f,args) = strip_comb app
   398           val _ = case f of Const(_,_) => ()
   399 			  | Free(s,_)  => 
   400 			      if isMeta s 
   401 			      then raise CLAUSE("Function Not First Order 2", f)
   402 			      else ()
   403 			  | _ => raise CLAUSE("Function Not First Order 3", f);
   404 	  val (funName,(contys,ts1),funcs) = fun_name_type f args
   405 	  val (args',(ts2,funcs')) = terms_of args
   406       in
   407 	  (Fun(funName,contys,args'), 
   408 	   (union_all (ts1::ts2), 
   409 	    union_all(funcs::funcs')))
   410       end
   411   | term_of t = raise CLAUSE("Function Not First Order 4", t)
   412 and terms_of ts =  
   413       let val (args, ts_funcs) = ListPair.unzip (map term_of ts)
   414       in
   415 	  (args, ListPair.unzip ts_funcs)
   416       end
   417 
   418 
   419 fun pred_of (Const("op =", typ), args) =
   420       let val arg_typ = eq_arg_type typ 
   421 	  val (args',(ts,funcs)) = terms_of args
   422 	  val equal_name = make_fixed_const "op ="
   423       in
   424 	  (Predicate(equal_name,[arg_typ],args'),
   425 	   union_all ts, 
   426 	   [((make_fixed_var equal_name), 2)], 
   427 	   union_all funcs)
   428       end
   429   | pred_of (pred,args) = 
   430       let val (predName,(predType,ts1), pfuncs) = pred_name_type pred
   431 	  val (args',(ts2,ffuncs)) = terms_of args
   432 	  val ts3 = union_all (ts1::ts2)
   433 	  val ffuncs' = union_all ffuncs
   434 	  val newfuncs = pfuncs union ffuncs'
   435 	  val arity = 
   436 	    case pred of
   437 		Const (c,T) => num_typargs(c,T) + length args
   438 	      | _ => length args
   439       in
   440 	  (Predicate(predName,predType,args'), ts3, 
   441 	   [(predName, arity)], newfuncs)
   442       end;
   443 
   444 
   445 (*Treatment of literals, possibly negated or tagged*)
   446 fun predicate_of ((Const("Not",_) $ P), polarity, tag) =
   447       predicate_of (P, not polarity, tag)
   448   | predicate_of ((Const("HOL.tag",_) $ P), polarity, tag) =
   449       predicate_of (P, polarity, true)
   450   | predicate_of (term,polarity,tag) =
   451         (pred_of (strip_comb term), polarity, tag);
   452 
   453 fun literals_of_term1 args (Const("Trueprop",_) $ P) = literals_of_term1 args P
   454   | literals_of_term1 (args as (lits, ts, preds, funcs)) (Const("op |",_) $ P $ Q) = 
   455       let val (lits', ts', preds', funcs') = literals_of_term1 args P
   456       in
   457 	  literals_of_term1 (lits', ts', preds' union preds, funcs' union funcs) Q
   458       end
   459   | literals_of_term1 (lits, ts, preds, funcs) P =
   460       let val ((pred, ts', preds', funcs'), pol, tag) = predicate_of (P,true,false)
   461 	  val lits' = Literal(pol,pred,tag) :: lits
   462       in
   463 	  (lits', ts union ts', preds' union preds, funcs' union funcs)
   464       end;
   465 
   466 
   467 val literals_of_term = literals_of_term1 ([],[],[],[]);
   468 
   469 
   470 fun predicate_ord (Predicate(predname1,_,_),Predicate(predname2,_,_)) = string_ord (predname1,predname2);
   471 
   472 
   473 fun literal_ord (Literal(false,_,_),Literal(true,_,_)) = LESS
   474   | literal_ord (Literal(true,_,_),Literal(false,_,_)) = GREATER
   475   | literal_ord (Literal(_,pred1,_),Literal(_,pred2,_)) = predicate_ord(pred1,pred2);
   476 
   477 fun sort_lits lits = sort literal_ord lits;
   478 
   479 
   480 
   481 (* FIX: not sure what to do with these funcs *)
   482 
   483 (*Make literals for sorted type variables*) 
   484 fun sorts_on_typs (_, [])   = ([]) 
   485   | sorts_on_typs (v, "HOL.type" :: s) =
   486       sorts_on_typs (v,s)   (*Ignore sort "type"*)
   487   | sorts_on_typs ((FOLTVar indx), (s::ss)) =
   488       LTVar((make_type_class s) ^ 
   489         "(" ^ (make_schematic_type_var indx) ^ ")") :: 
   490       (sorts_on_typs ((FOLTVar indx), ss))
   491   | sorts_on_typs ((FOLTFree x), (s::ss)) =
   492       LTFree((make_type_class s) ^ "(" ^ (make_fixed_type_var x) ^ ")") :: 
   493       (sorts_on_typs ((FOLTFree x), ss));
   494 
   495 
   496 (*UGLY: seems to be parsing the "show sorts" output, removing anything that
   497   starts with a left parenthesis.*)
   498 fun remove_type str = hd (String.fields (fn c => c = #"(") str);
   499 
   500 fun pred_of_sort (LTVar x) = ((remove_type x),1)
   501 |   pred_of_sort (LTFree x) = ((remove_type x),1)
   502 
   503 
   504 
   505 
   506 (*Given a list of sorted type variables, return two separate lists.
   507   The first is for TVars, the second for TFrees.*)
   508 fun add_typs_aux [] preds  = ([],[], preds)
   509   | add_typs_aux ((FOLTVar indx,s)::tss) preds = 
   510       let val vs = sorts_on_typs (FOLTVar indx, s)
   511           val preds' = (map pred_of_sort vs)@preds
   512 	  val (vss,fss, preds'') = add_typs_aux tss preds'
   513       in
   514 	  (vs union vss, fss, preds'')
   515       end
   516   | add_typs_aux ((FOLTFree x,s)::tss) preds  =
   517       let val fs = sorts_on_typs (FOLTFree x, s)
   518           val preds' = (map pred_of_sort fs)@preds
   519 	  val (vss,fss, preds'') = add_typs_aux tss preds'
   520       in
   521 	  (vss, fs union fss, preds'')
   522       end;
   523 
   524 fun add_typs_aux2 [] = ([],[])
   525   | add_typs_aux2 ((FOLTVar indx,s)::tss) =
   526     let val vs = sorts_on_typs (FOLTVar indx,s)
   527 	val (vss,fss) = add_typs_aux2 tss
   528     in
   529 	(vs union vss,fss)
   530     end
   531   | add_typs_aux2 ((FOLTFree x,s)::tss) =
   532     let val fs = sorts_on_typs (FOLTFree x,s)
   533 	val (vss,fss) = add_typs_aux2 tss
   534     in
   535 	(vss,fs union fss)
   536     end;
   537 
   538 
   539 fun add_typs (Clause cls) preds  = add_typs_aux (#types_sorts cls) preds 
   540 
   541 
   542 (** make axiom clauses, hypothesis clauses and conjecture clauses. **)
   543 
   544 fun get_tvar_strs [] = []
   545   | get_tvar_strs ((FOLTVar indx,s)::tss) = 
   546       let val vstr = make_schematic_type_var indx
   547       in
   548 	  vstr ins (get_tvar_strs tss)
   549       end
   550   | get_tvar_strs((FOLTFree x,s)::tss) = distinct (get_tvar_strs tss)
   551 
   552 (* FIX add preds and funcs to add typs aux here *)
   553 
   554 fun make_axiom_clause_thm thm (ax_name,cls_id) =
   555     let val (lits,types_sorts, preds, funcs) = literals_of_term (prop_of thm)
   556 	val lits' = sort_lits lits
   557 	val (tvar_lits,tfree_lits, preds) = add_typs_aux types_sorts preds 
   558         val tvars = get_tvar_strs types_sorts
   559     in 
   560 	make_clause(cls_id,ax_name,Axiom,
   561 	            lits',types_sorts,tvar_lits,tfree_lits,
   562 	            tvars, preds, funcs)
   563     end;
   564 
   565 
   566 (* check if a clause is FOL first*)
   567 fun make_conjecture_clause n t =
   568     let val _ = check_is_fol_term t
   569 	    handle TERM("check_is_fol_term",_) => raise CLAUSE("Goal is not FOL",t)
   570 	val (lits,types_sorts, preds, funcs) = literals_of_term t
   571 	val (tvar_lits,tfree_lits, preds) = add_typs_aux types_sorts preds 
   572         val tvars = get_tvar_strs types_sorts
   573     in
   574 	make_clause(n,"conjecture",Conjecture,
   575 	            lits,types_sorts,tvar_lits,tfree_lits,
   576 	            tvars, preds, funcs)
   577     end;
   578     
   579 fun make_conjecture_clauses_aux _ [] = []
   580   | make_conjecture_clauses_aux n (t::ts) =
   581       make_conjecture_clause n t :: make_conjecture_clauses_aux (n+1) ts
   582 
   583 val make_conjecture_clauses = make_conjecture_clauses_aux 0
   584 
   585 
   586 (*before converting an axiom clause to "clause" format, check if it is FOL*)
   587 fun make_axiom_clause term (ax_name,cls_id) =
   588     let val _ = check_is_fol_term term 
   589 	    handle TERM("check_is_fol_term",_) => raise CLAUSE("Axiom is not FOL", term) 
   590 	val (lits,types_sorts, preds,funcs) = literals_of_term term
   591 	val lits' = sort_lits lits
   592 	val (tvar_lits,tfree_lits, preds) = add_typs_aux types_sorts preds
   593         val tvars = get_tvar_strs types_sorts	
   594     in 
   595 	make_clause(cls_id,ax_name,Axiom,
   596 	            lits',types_sorts,tvar_lits,tfree_lits,
   597 	            tvars, preds,funcs)
   598     end;
   599 
   600 
   601 
   602  
   603 (**** Isabelle arities ****)
   604 
   605 exception ARCLAUSE of string;
   606  
   607 
   608 type class = string; 
   609 type tcons = string; 
   610 
   611 
   612 datatype arLit = TConsLit of bool * (class * tcons * string list) | TVarLit of bool * (class * string);
   613  
   614 datatype arityClause =  
   615 	 ArityClause of {clause_id: clause_id,
   616 	  	         axiom_name: axiom_name,
   617 			 kind: kind,
   618 			 conclLit: arLit,
   619 			 premLits: arLit list};
   620 
   621 
   622 fun get_TVars 0 = []
   623   | get_TVars n = ("T_" ^ (Int.toString n)) :: get_TVars (n-1);
   624 
   625 
   626 
   627 fun pack_sort(_,[])  = raise ARCLAUSE("Empty Sort Found") 
   628   | pack_sort(tvar, [cls]) = [(make_type_class cls, tvar)] 
   629   | pack_sort(tvar, cls::srt) =  (make_type_class cls,tvar) :: (pack_sort(tvar, srt));
   630     
   631     
   632 fun make_TVarLit (b,(cls,str)) = TVarLit(b,(cls,str));
   633 fun make_TConsLit (b,(cls,tcons,tvars)) = TConsLit(b,(make_type_class cls,make_fixed_type_const tcons,tvars));
   634 
   635 fun make_axiom_arity_clause (tcons,n,(res,args)) =
   636    let val nargs = length args
   637        val tvars = get_TVars nargs
   638        val tvars_srts = ListPair.zip (tvars,args)
   639        val tvars_srts' = union_all(map pack_sort tvars_srts)
   640        val false_tvars_srts' = map (pair false) tvars_srts'
   641    in
   642       ArityClause {clause_id = n, kind = Axiom, 
   643                    axiom_name = tcons,
   644                    conclLit = make_TConsLit(true,(res,tcons,tvars)), 
   645                    premLits = map make_TVarLit false_tvars_srts'}
   646    end;
   647     
   648 (*The number of clauses generated from cls, including type clauses*)
   649 fun num_of_clauses (Clause cls) =
   650     let val num_tfree_lits = 
   651 	      if !keep_types then length (#tfree_type_literals cls)
   652 	      else 0
   653     in 	1 + num_tfree_lits  end;
   654 
   655 
   656 (**** Isabelle class relations ****)
   657 
   658 
   659 datatype classrelClause = 
   660 	 ClassrelClause of {clause_id: clause_id,
   661 			    subclass: class,
   662 			    superclass: class option};
   663 
   664 
   665 fun make_axiom_classrelClause n subclass superclass =
   666   ClassrelClause {clause_id = n,
   667                   subclass = subclass, superclass = superclass};
   668 
   669 
   670 fun classrelClauses_of_aux n sub [] = []
   671   | classrelClauses_of_aux n sub (sup::sups) =
   672       make_axiom_classrelClause n sub (SOME sup) :: classrelClauses_of_aux (n+1) sub sups;
   673 
   674 
   675 fun classrelClauses_of (sub,sups) = 
   676     case sups of [] => [make_axiom_classrelClause 0 sub NONE]
   677 	       | _ => classrelClauses_of_aux 0 sub sups;
   678 
   679 
   680 (***** Isabelle arities *****)
   681 
   682 
   683 fun arity_clause _ (tcons, []) = []
   684   | arity_clause n (tcons, ar::ars) =
   685       make_axiom_arity_clause (tcons,n,ar) :: 
   686       arity_clause (n+1) (tcons,ars);
   687 
   688 fun multi_arity_clause [] = []
   689   | multi_arity_clause (tcon_ar :: tcons_ars)  =
   690       arity_clause 0 tcon_ar  @  multi_arity_clause tcons_ars 
   691 
   692 fun arity_clause_thy thy =
   693   let val arities = #arities (Type.rep_tsig (Sign.tsig_of thy))
   694   in multi_arity_clause (Symtab.dest arities) end;
   695 
   696 
   697 (* Isabelle classes *)
   698 
   699 type classrelClauses = classrelClause list Symtab.table;
   700 
   701 val classrel_of = #2 o #classes o Type.rep_tsig o Sign.tsig_of;
   702 fun classrel_clauses_classrel (C: Sorts.classes) = map classrelClauses_of (Graph.dest C);
   703 val classrel_clauses_thy = List.concat o classrel_clauses_classrel o classrel_of;
   704 
   705 
   706 
   707 (****!!!! Changed for typed equality !!!!****)
   708 
   709 fun wrap_eq_type typ t = eq_typ_wrapper ^"(" ^ t ^ "," ^ typ ^ ")";
   710 
   711 (*Only need to wrap equality's arguments with "typeinfo" if the output clauses are typed 
   712  and if we specifically ask for types to be included.   *)
   713 fun string_of_equality (typ,terms) =
   714       let val [tstr1,tstr2] = map string_of_term terms
   715 	  val typ' = string_of_fol_type typ
   716       in
   717 	  if !keep_types andalso !special_equal 
   718 	  then "equal(" ^ (wrap_eq_type typ' tstr1) ^ "," ^ 
   719 		 	  (wrap_eq_type typ' tstr2) ^ ")"
   720 	  else "equal(" ^ tstr1 ^ "," ^ tstr2 ^ ")"
   721       end
   722 and string_of_term (UVar(x,_)) = x
   723   | string_of_term (Fun("equal",[typ],terms)) = string_of_equality(typ,terms)
   724   | string_of_term (Fun (name,typs,[])) = name (*Overloaded consts like 0 don't get types!*)
   725   | string_of_term (Fun (name,typs,terms)) = 
   726       let val terms_as_strings = map string_of_term terms
   727 	  val typs' = if !keep_types then map string_of_fol_type typs else []
   728       in  name ^ (paren_pack (terms_as_strings @ typs'))  end
   729   | string_of_term _ = error "string_of_term";      
   730 
   731 (* before output the string of the predicate, check if the predicate corresponds to an equality or not. *)
   732 fun string_of_predicate (Predicate("equal",[typ],terms)) = string_of_equality(typ,terms)
   733   | string_of_predicate (Predicate(name,typs,terms)) = 
   734       let val terms_as_strings = map string_of_term terms
   735 	  val typs' = if !keep_types then map string_of_fol_type typs else []
   736       in  name ^ (paren_pack (terms_as_strings @ typs'))  end
   737   | string_of_predicate _ = error "string_of_predicate";      
   738 
   739 
   740 fun string_of_clausename (cls_id,ax_name) = 
   741     clause_prefix ^ ascii_of ax_name ^ "_" ^ Int.toString cls_id;
   742 
   743 fun string_of_type_clsname (cls_id,ax_name,idx) = 
   744     string_of_clausename (cls_id,ax_name) ^ "_tcs" ^ (Int.toString idx);
   745     
   746 
   747 (********************************)
   748 (* Code for producing DFG files *)
   749 (********************************)
   750 
   751 fun dfg_literal (Literal(pol,pred,tag)) =
   752     let val pred_string = string_of_predicate pred
   753     in
   754 	if pol then pred_string else "not(" ^pred_string ^ ")"  
   755     end;
   756 
   757 
   758 (* FIX: what does this mean? *)
   759 (*fun dfg_of_typeLit (LTVar x) = "not(" ^ x ^ ")"
   760   | dfg_of_typeLit (LTFree x) = "(" ^ x ^ ")";*)
   761 
   762 fun dfg_of_typeLit (LTVar x) =  x 
   763   | dfg_of_typeLit (LTFree x) = x ;
   764  
   765 (*Make the string of universal quantifiers for a clause*)
   766 fun forall_open ([],[]) = ""
   767   | forall_open (vars,tvars) = "forall([" ^ (commas (tvars@vars))^ "],\n"
   768 
   769 fun forall_close ([],[]) = ""
   770   | forall_close (vars,tvars) = ")"
   771 
   772 fun gen_dfg_cls (cls_id,ax_name,knd,lits,tvars,vars) = 
   773     "clause( %(" ^ knd ^ ")\n" ^ forall_open(vars,tvars) ^ 
   774     "or(" ^ lits ^ ")" ^ forall_close(vars,tvars) ^ ",\n" ^ 
   775     string_of_clausename (cls_id,ax_name) ^  ").";
   776 
   777 fun gen_dfg_type_cls (cls_id,ax_name,knd,tfree_lit,idx,tvars,vars) = 
   778     "clause( %(" ^ knd ^ ")\n" ^ forall_open(vars,tvars) ^ 
   779     "or( " ^ tfree_lit ^ ")" ^ forall_close(vars,tvars) ^ ",\n" ^ 
   780     string_of_type_clsname (cls_id,ax_name,idx) ^  ").";
   781 
   782 fun dfg_clause_aux (Clause cls) = 
   783   let val lits = map dfg_literal (#literals cls)
   784       val tvar_lits_strs = 
   785 	  if !keep_types then map dfg_of_typeLit (#tvar_type_literals cls) 
   786 	  else []
   787       val tfree_lits =
   788           if !keep_types then map dfg_of_typeLit (#tfree_type_literals cls)
   789           else []
   790   in
   791       (tvar_lits_strs @ lits, tfree_lits)
   792   end; 
   793 
   794 
   795 fun dfg_folterms (Literal(pol,pred,tag)) = 
   796   let val Predicate (predname, _, folterms) = pred
   797   in  folterms  end
   798 
   799  
   800 fun get_uvars (UVar(a,typ)) = [a] 
   801 |   get_uvars (Fun (_,typ,tlist)) = union_all(map get_uvars tlist)
   802 
   803 
   804 fun is_uvar (UVar _) = true
   805 |   is_uvar (Fun _) = false;
   806 
   807 fun uvar_name (UVar(a,_)) = a
   808 |   uvar_name (Fun (a,_,_)) = raise CLAUSE("Not a variable", Const(a,dummyT));
   809 
   810 fun dfg_vars (Clause cls) =
   811     let val lits = #literals cls
   812         val folterms = List.concat (map dfg_folterms lits)
   813     in 
   814         union_all(map get_uvars folterms)
   815     end
   816 
   817 
   818 fun dfg_tvars (Clause cls) =(#tvars cls)
   819 
   820 
   821 	
   822 (* make this return funcs and preds too? *)
   823 fun string_of_predname (Predicate("equal",_,terms)) = "EQUALITY"
   824   | string_of_predname (Predicate(name,_,terms)) = name
   825     
   826 	
   827 
   828 fun concat_with sep []  = ""
   829   | concat_with sep [x] = "(" ^ x ^ ")"
   830   | concat_with sep (x::xs) = "(" ^ x ^ ")" ^  sep ^ (concat_with sep xs);
   831 
   832 fun dfg_pred (Literal(pol,pred,tag)) ax_name = 
   833     (string_of_predname pred) ^ " " ^ ax_name
   834 
   835 fun dfg_clause cls =
   836     let val (lits,tfree_lits) = dfg_clause_aux cls 
   837              (*"lits" includes the typing assumptions (TVars)*)
   838         val vars = dfg_vars cls
   839         val tvars = dfg_tvars cls
   840 	val knd = string_of_kind cls
   841 	val lits_str = commas lits
   842 	val cls_id = get_clause_id cls
   843 	val axname = get_axiomName cls
   844 	val cls_str = gen_dfg_cls(cls_id,axname,knd,lits_str,tvars, vars) 			
   845         fun typ_clss k [] = []
   846           | typ_clss k (tfree :: tfrees) = 
   847               (gen_dfg_type_cls(cls_id,axname,knd,tfree,k, tvars,vars)) :: 
   848               (typ_clss (k+1) tfrees)
   849     in 
   850 	cls_str :: (typ_clss 0 tfree_lits)
   851     end;
   852 
   853 fun string_of_arity (name, num) =  name ^ "," ^ (Int.toString num) 
   854 
   855 fun string_of_preds preds = 
   856   "predicates[" ^ (concat_with ", " (map string_of_arity preds)) ^ "].\n";
   857 
   858 fun string_of_funcs funcs =
   859   "functions[" ^ (concat_with ", " (map string_of_arity funcs)) ^ "].\n" ;
   860 
   861 
   862 fun string_of_symbols predstr funcstr = 
   863   "list_of_symbols.\n" ^ predstr  ^ funcstr  ^ "end_of_list.\n\n";
   864 
   865 
   866 fun string_of_axioms axstr = 
   867   "list_of_clauses(axioms,cnf).\n" ^ axstr ^ "end_of_list.\n\n";
   868 
   869 
   870 fun string_of_conjectures conjstr = 
   871   "list_of_clauses(conjectures,cnf).\n" ^ conjstr ^ "end_of_list.\n\n";
   872 
   873 fun string_of_descrip () = 
   874   "list_of_descriptions.\nname({*[ File     : ],[ Names    :]*}).\nauthor({*[ Source   :]*}).\nstatus(unknown).\ndescription({*[ Refs     :]*}).\nend_of_list.\n\n"
   875 
   876 
   877 fun string_of_start name = "%------------------------------------------------------------------------------\nbegin_problem(" ^ name ^ ").\n\n";
   878 
   879 
   880 fun string_of_end () = "end_problem.\n%------------------------------------------------------------------------------";
   881 
   882 
   883 fun clause2dfg cls =
   884     let val (lits,tfree_lits) = dfg_clause_aux cls 
   885             (*"lits" includes the typing assumptions (TVars)*)
   886 	val cls_id = get_clause_id cls
   887 	val ax_name = get_axiomName cls
   888         val vars = dfg_vars cls
   889         val tvars = dfg_tvars cls
   890         val funcs = funcs_of_cls cls
   891         val preds = preds_of_cls cls
   892 	val knd = string_of_kind cls
   893 	val lits_str = commas lits
   894 	val cls_str = gen_dfg_cls(cls_id,ax_name,knd,lits_str,tvars,vars) 
   895     in
   896 	(cls_str,tfree_lits) 
   897     end;
   898 
   899 
   900 
   901 fun tfree_dfg_clause tfree_lit =
   902   "clause( %(conjecture)\n" ^ "or( " ^ tfree_lit ^ "),\n" ^ "tfree_tcs" ^ ")."
   903 
   904 
   905 fun gen_dfg_file probname axioms conjectures funcs preds = 
   906     let val axstrs_tfrees = (map clause2dfg axioms)
   907 	val (axstrs, atfrees) = ListPair.unzip axstrs_tfrees
   908         val axstr = (space_implode "\n" axstrs) ^ "\n\n"
   909         val conjstrs_tfrees = (map clause2dfg conjectures)
   910 	val (conjstrs, atfrees) = ListPair.unzip conjstrs_tfrees
   911         val tfree_clss = map tfree_dfg_clause (union_all atfrees) 
   912         val conjstr = (space_implode "\n" (tfree_clss@conjstrs)) ^ "\n\n"
   913         val funcstr = string_of_funcs funcs
   914         val predstr = string_of_preds preds
   915     in
   916        (string_of_start probname) ^ (string_of_descrip ()) ^ 
   917        (string_of_symbols funcstr predstr) ^  
   918        (string_of_axioms axstr) ^
   919        (string_of_conjectures conjstr) ^ (string_of_end ())
   920     end;
   921    
   922 fun clauses2dfg [] probname axioms conjectures funcs preds = 
   923       let val funcs' = (union_all(map funcs_of_cls axioms)) @ funcs
   924 	  val preds' = (union_all(map preds_of_cls axioms)) @ preds
   925       in
   926 	 gen_dfg_file probname axioms conjectures funcs' preds' 
   927       end
   928  | clauses2dfg (cls::clss) probname axioms conjectures funcs preds = 
   929      let val (lits,tfree_lits) = dfg_clause_aux cls
   930 	       (*"lits" includes the typing assumptions (TVars)*)
   931 	 val cls_id = get_clause_id cls
   932 	 val ax_name = get_axiomName cls
   933 	 val vars = dfg_vars cls
   934 	 val tvars = dfg_tvars cls
   935 	 val funcs' = (funcs_of_cls cls) union funcs
   936 	 val preds' = (preds_of_cls cls) union preds
   937 	 val knd = string_of_kind cls
   938 	 val lits_str = concat_with ", " lits
   939 	 val axioms' = if knd = "axiom" then (cls::axioms) else axioms
   940 	 val conjectures' = 
   941 	     if knd = "conjecture" then (cls::conjectures) else conjectures
   942      in
   943 	 clauses2dfg clss probname axioms' conjectures' funcs' preds' 
   944      end;
   945 
   946 
   947 fun string_of_arClauseID (ArityClause {clause_id,axiom_name,...}) =
   948     arclause_prefix ^ ascii_of axiom_name ^ "_" ^ Int.toString clause_id;
   949 
   950 fun string_of_arKind (ArityClause arcls) = name_of_kind(#kind arcls);
   951 
   952 (*FIXME!!! currently is TPTP format!*)
   953 fun dfg_of_arLit (TConsLit(b,(c,t,args))) =
   954       let val pol = if b then "++" else "--"
   955 	  val arg_strs = paren_pack args
   956       in 
   957 	  pol ^ c ^ "(" ^ t ^ arg_strs ^ ")"
   958       end
   959   | dfg_of_arLit (TVarLit(b,(c,str))) =
   960       let val pol = if b then "++" else "--"
   961       in
   962 	  pol ^ c ^ "(" ^ str ^ ")"
   963       end;
   964     
   965 
   966 fun dfg_of_conclLit (ArityClause arcls) = dfg_of_arLit (#conclLit arcls);
   967      
   968 
   969 fun dfg_of_premLits (ArityClause arcls) = map dfg_of_arLit (#premLits arcls);
   970 		
   971 
   972 
   973 (*FIXME: would this have variables in a forall? *)
   974 
   975 fun dfg_arity_clause arcls = 
   976   let val arcls_id = string_of_arClauseID arcls
   977       val concl_lit = dfg_of_conclLit arcls
   978       val prems_lits = dfg_of_premLits arcls
   979       val knd = string_of_arKind arcls
   980       val all_lits = concl_lit :: prems_lits
   981   in
   982       "clause( %(" ^ knd ^ ")\n" ^  "or( " ^ (bracket_pack all_lits) ^ ")),\n" ^
   983        arcls_id ^  ")."
   984   end;
   985 
   986 
   987 (********************************)
   988 (* code to produce TPTP files   *)
   989 (********************************)
   990 
   991 fun tptp_literal (Literal(pol,pred,tag)) =
   992     let val pred_string = string_of_predicate pred
   993 	val tagged_pol = 
   994 	      if (tag andalso !tagged) then (if pol then "+++" else "---")
   995 	      else (if pol then "++" else "--")
   996      in
   997 	tagged_pol ^ pred_string
   998     end;
   999 
  1000 fun tptp_of_typeLit (LTVar x) = "--" ^ x
  1001   | tptp_of_typeLit (LTFree x) = "++" ^ x;
  1002  
  1003 
  1004 fun gen_tptp_cls (cls_id,ax_name,knd,lits) = 
  1005     "input_clause(" ^ string_of_clausename (cls_id,ax_name) ^ "," ^ 
  1006     knd ^ "," ^ lits ^ ").";
  1007 
  1008 fun gen_tptp_type_cls (cls_id,ax_name,knd,tfree_lit,idx) = 
  1009     "input_clause(" ^ string_of_type_clsname (cls_id,ax_name,idx) ^ "," ^ 
  1010     knd ^ ",[" ^ tfree_lit ^ "]).";
  1011 
  1012 fun tptp_type_lits (Clause cls) = 
  1013     let val lits = map tptp_literal (#literals cls)
  1014 	val tvar_lits_strs =
  1015 	      if !keep_types 
  1016 	      then (map tptp_of_typeLit (#tvar_type_literals cls)) 
  1017 	      else []
  1018 	val tfree_lits = 
  1019 	      if !keep_types
  1020 	      then (map tptp_of_typeLit (#tfree_type_literals cls)) 
  1021 	      else []
  1022     in
  1023 	(tvar_lits_strs @ lits, tfree_lits)
  1024     end; 
  1025 
  1026 fun tptp_clause cls =
  1027     let val (lits,tfree_lits) = tptp_type_lits cls 
  1028             (*"lits" includes the typing assumptions (TVars)*)
  1029 	val cls_id = get_clause_id cls
  1030 	val ax_name = get_axiomName cls
  1031 	val knd = string_of_kind cls
  1032 	val lits_str = bracket_pack lits
  1033 	val cls_str = gen_tptp_cls(cls_id,ax_name,knd,lits_str) 			 
  1034 	fun typ_clss k [] = []
  1035           | typ_clss k (tfree :: tfrees) = 
  1036               gen_tptp_type_cls(cls_id,ax_name,knd,tfree,k) :: 
  1037               typ_clss (k+1) tfrees
  1038     in 
  1039 	cls_str :: (typ_clss 0 tfree_lits)
  1040     end;
  1041 
  1042 fun clause2tptp cls =
  1043     let val (lits,tfree_lits) = tptp_type_lits cls 
  1044             (*"lits" includes the typing assumptions (TVars)*)
  1045 	val cls_id = get_clause_id cls
  1046 	val ax_name = get_axiomName cls
  1047 	val knd = string_of_kind cls
  1048 	val lits_str = bracket_pack lits
  1049 	val cls_str = gen_tptp_cls(cls_id,ax_name,knd,lits_str) 
  1050     in
  1051 	(cls_str,tfree_lits) 
  1052     end;
  1053 
  1054 
  1055 fun tfree_clause tfree_lit =
  1056     "input_clause(" ^ "tfree_tcs," ^ "conjecture" ^ ",[" ^ tfree_lit ^ "]).";
  1057 
  1058 
  1059 fun tptp_of_arLit (TConsLit(b,(c,t,args))) =
  1060       let val pol = if b then "++" else "--"
  1061 	  val  arg_strs = paren_pack args
  1062       in 
  1063 	  pol ^ c ^ "(" ^ t ^ arg_strs ^ ")"
  1064       end
  1065   | tptp_of_arLit (TVarLit(b,(c,str))) =
  1066       let val pol = if b then "++" else "--"
  1067       in
  1068 	  pol ^ c ^ "(" ^ str ^ ")"
  1069       end;
  1070     
  1071 
  1072 fun tptp_of_conclLit (ArityClause arcls) = tptp_of_arLit (#conclLit arcls);
  1073      
  1074 fun tptp_of_premLits (ArityClause arcls) = map tptp_of_arLit (#premLits arcls);
  1075 		
  1076 fun tptp_arity_clause arcls = 
  1077     let val arcls_id = string_of_arClauseID arcls
  1078 	val concl_lit = tptp_of_conclLit arcls
  1079 	val prems_lits = tptp_of_premLits arcls
  1080 	val knd = string_of_arKind arcls
  1081 	val all_lits = concl_lit :: prems_lits
  1082     in
  1083 	"input_clause(" ^ arcls_id ^ "," ^ knd ^ "," ^ 
  1084 	(bracket_pack all_lits) ^ ")."
  1085     end;
  1086 
  1087 fun tptp_classrelLits sub sup = 
  1088     let val tvar = "(T)"
  1089     in 
  1090 	case sup of NONE => "[++" ^ sub ^ tvar ^ "]"
  1091 		  | (SOME supcls) =>  "[--" ^ sub ^ tvar ^ ",++" ^ supcls ^ tvar ^ "]"
  1092     end;
  1093 
  1094 
  1095 fun tptp_classrelClause (ClassrelClause {clause_id,subclass,superclass,...}) =
  1096     let val relcls_id = clrelclause_prefix ^ ascii_of subclass ^ "_" ^ 
  1097                         Int.toString clause_id
  1098 	val lits = tptp_classrelLits (make_type_class subclass) 
  1099 	                (Option.map make_type_class superclass)
  1100     in
  1101 	"input_clause(" ^ relcls_id ^ ",axiom," ^ lits ^ ")."
  1102     end; 
  1103 
  1104 end;