(* Title:  BaseDefinitions/rule-set.sml

    Author: Walther Neuper

    (c) due to copyright terms

 In ISAC a Rule_Set serves rewriting. Know_Store holds all rule-sets for ubiquitous access.

 *)

 signature RULE_SET =

 sig

   datatype T = datatype Rule_Def.rule_set

   eqtype id

   val id: T -> string

   val rep: T -> {calc: Rule_Def.calc list, erls: T, errpats: Rule_Def.errpatID list, id: string,

     preconds: term list, rew_ord: Rewrite_Ord.rew_ord, rules: Rule_Def.rule list, scr: Rule_Def.program, srls: T}

   val append_rules: string -> T -> Rule_Def.rule list -> T

   val keep_unique_rules: string -> T ->  Rule_Def.rule list -> T

   val merge: string -> T -> T -> T

   val get_rules: T -> Rule_Def.rule list

 (*val rule2rls': Rule.rule -> string*)

   val id_from_rule: Rule.rule -> string

   val contains: Rule.rule -> T -> bool

   type for_kestore

   val equal: (''a * ('b * 'c)) * (''a * ('d * 'e)) -> bool

   val to_kestore: for_kestore list * for_kestore list -> for_kestore list

 (*/------- this will disappear eventually ----------------------------------------------------\*)

   val empty: T

   type rrlsstate = term * term * Rule_Def.rule list list * (Rule_Def.rule * (term * term list)) list

   val e_rrlsstate: rrlsstate

   val e_rrls: T

 (*\------- this will disappear eventually ----------------------------------------------------/*)

 (* ---- for tests only: shifted from below to remove the Warning "unused" at fun.def. --------- *)

   (*NONE*)

 (*/-------------------------------------------------------- ! aktivate for Test_Isac BEGIN ---\* )

   val insert_merge: for_kestore -> for_kestore list -> for_kestore list

 ( *\--- ! aktivate for Test_Isac END ----------------------------------------------------------/*)

 end

 (**)

 structure Rule_Set(**): RULE_SET(**) =

 struct

 (**)

 datatype T = datatype Rule_Def.rule_set;

 type id = string;

 (*/------- this will disappear eventually ----------------------------------------------------\*)

 fun dummy_ord (_: (term * term) list) (_: term, _: term) = true;

 val empty =

   Rule_Def.Repeat {id = "empty", preconds = [], rew_ord = ("dummy_ord", dummy_ord), erls = Rule_Def.Empty,

     srls = Rule_Def.Empty, calc = [], rules = [], errpatts = [], scr = Rule_Def.Empty_Prog}

 (*\------- this will disappear eventually ----------------------------------------------------/*)

 val id = Rule.set_id;

 fun rep Rule_Def.Empty = rep empty

   | rep (Rule_Def.Repeat {id, preconds, rew_ord, erls, srls, calc, errpatts, rules, scr}) =

     {id = id, preconds = preconds, rew_ord = rew_ord, erls = erls, srls = srls, errpats = errpatts,

       calc = calc, rules = rules, scr = scr}

   | rep (Rule_Def.Sequence {id, preconds, rew_ord, erls, srls, calc, errpatts, rules, scr}) =

     {id = id, preconds = preconds, rew_ord = rew_ord, erls = erls, srls = srls, errpats = errpatts,

       calc = calc, rules = rules, scr = scr}

   | rep (Rule_Def.Rrls _)  = rep empty

 fun append_rules id Rule_Def.Empty _ = raise ERROR ("append_rules: with \"" ^ id ^ "\" not for Rule_Def.Empty")

   | append_rules id (Rule_Def.Repeat {id = _, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

 			rules = rs, errpatts = errpatts, scr = sc}) r =

     Rule_Def.Repeat {id = id, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

       rules = rs @ r, errpatts = errpatts, scr = sc}

   | append_rules id (Rule_Def.Sequence {id = _, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

 			rules = rs, errpatts = errpatts, scr = sc}) r =

     Rule_Def.Sequence {id = id, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

       rules = rs @ r, errpatts = errpatts, scr = sc}

   | append_rules id (Rule_Def.Rrls _) _ = raise ERROR ("append_rules: not for reverse-rewrite-rule-set " ^ id);

 fun merge_ids rls1 rls2 =

   let 

     val id1 = (#id o rep) rls1

     val id2 = (#id o rep) rls2

   in

     if id1 = id2 then id1 else "merged_" ^ id1 ^ "_" ^ id2

   end

 fun merge _ Rule_Def.Empty rls = rls

   | merge _ rls Rule_Def.Empty = rls

   | merge _ (Rrls x) _ = Rrls x (* required for merging Theory_Data *)

   | merge _ _ (Rrls x) = Rrls x

   | merge id

 	  (Rule_Def.Repeat {preconds = pc1, rew_ord = ro1, erls = er1, srls = sr1, calc = ca1,

 	    rules = rs1, errpatts = eps1, scr = sc1, ...})

 	  (Rule_Def.Repeat {preconds = pc2, erls = er2, srls = sr2, calc = ca2,

 	    rules = rs2, errpatts = eps2, ...})

     =

 	  Rule_Def.Repeat {id = id, rew_ord = ro1, scr = sc1,

 	    preconds = union (op =) pc1 pc2,	    

 	    erls = merge (merge_ids er1 er2) er1 er2,

 	    srls = merge (merge_ids sr1 sr2) sr1 sr2,

 	    calc = union Exec_Def.calc_eq ca1 ca2,

 		  rules = union Rule.equal rs1 rs2,

       errpatts = union (op =) eps1 eps2}

   | merge id

 	  (Rule_Def.Sequence {preconds = pc1, rew_ord = ro1, erls = er1, srls = sr1, calc = ca1,

 	    rules = rs1, errpatts = eps1, scr = sc1, ...})

 	  (Rule_Def.Sequence {preconds = pc2, erls = er2, srls = sr2, calc = ca2,

 	    rules = rs2, errpatts = eps2, ...})

     =

 	  Rule_Def.Sequence {id = id, rew_ord = ro1, scr = sc1,

 	    preconds = union (op =) pc1 pc2,	    

 	    erls = merge (merge_ids er1 er2) er1 er2,

 	    srls = merge (merge_ids sr1 sr2) sr1 sr2,

 	    calc = union Exec_Def.calc_eq ca1 ca2,

 		  rules = union Rule.equal rs1 rs2,

       errpatts = union (op =) eps1 eps2}

   | merge id _ _ = error ("merge: \"" ^ id ^ 

     "\"; not for reverse-rewrite-rule-sets and not for mixed Rls -- Rule_Def.Sequence");

 (* datastructure for KEStore_Elems, intermediate for thehier *)

 type for_kestore = 

   (id *     (* id unique within Isac *)

   (ThyC.id *  (* just for assignment in thehier, not appropriate for parsing etc *)

     T))     (* ((#id o rep) T) = id   by coding discipline *)

 fun equal ((id1, (_, _)), (id2, (_, _))) = id1 = id2

 fun insert_merge (re as (id, (thyID, r1))) ys = 

     case get_index (fn y => if curry equal re y then SOME y else NONE) ys of

       NONE => re :: ys

     | SOME (i, (_, (_, r2))) => 

       let

         val r12 = merge id r1 r2

       in list_update ys i (id, (thyID, r12)) end

 fun to_kestore (s1, s2) = fold insert_merge s1 s2;

 (* used only for one hack *)

 fun keep_unique_rules id 

      (Rule_Def.Repeat {id = _, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

   		  rules = rs, errpatts = eps, scr = sc}) r =

       Rule_Def.Repeat {id = id, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

   	    rules = gen_rems Rule.equal (rs, r),

   	    errpatts = eps,

   	    scr = sc}

   | keep_unique_rules id

      (Rule_Def.Sequence {id = _, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

   		  rules = rs, errpatts = eps, scr = sc}) r =

       Rule_Def.Sequence {id = id, preconds = pc, rew_ord = ro, erls = er, srls = sr, calc = ca,

   	    rules = gen_rems Rule.equal (rs, r),

   	    errpatts = eps,

   	    scr = sc}

   | keep_unique_rules id (Rule_Def.Rrls _) _ = raise ERROR ("keep_unique_rules: not for reverse-rewrite-rule-set "^id)

   | keep_unique_rules _ rls _ = raise ERROR ("remove_rls called with " ^ id rls);

 fun get_rules Rule_Def.Empty = []

   | get_rules (Rule_Def.Repeat {rules, ...}) = rules

   | get_rules (Rule_Def.Sequence {rules, ...}) = rules

   | get_rules (Rule_Def.Rrls _) = [];

 fun id_from_rule (Rule.Rls_ rls) = id rls

   | id_from_rule r = raise ERROR ("id_from_rule: not defined for " ^ Rule.to_string r);

 (* check if a rule is contained in a rule-set (recursivley down in Rls_);

    this rule can even be a rule-set itself                             *)

 fun contains r rls = 

   let 

     fun (*find (_, Rls_ rls) = finds (get_rules rls)

       | find r12 = equal r12

     and*) finds [] = false

     | finds (r1 :: rs) = if Rule.equal (r, r1) then true else finds rs

   in 

     finds (get_rules rls) 

   end

 (*/------- this will disappear eventually -----------\*)

 type rrlsstate =  (* state for reverse rewriting, comments see type rule and scr | Rfuns *)

   (term * term * Rule_Def.rule list list * (Rule_Def.rule * (term * term list)) list);

 val e_rrlsstate = (UnparseC.term_empty, UnparseC.term_empty, [[Rule_Def.Erule]], [(Rule_Def.Erule, (UnparseC.term_empty, []))]) : rrlsstate;

 local           

     fun ii (_: term) = e_rrlsstate;

     fun no (_: term) = SOME (UnparseC.term_empty, [UnparseC.term_empty]);

     fun lo (_: Rule_Def.rule list list) (_: term) (_: Rule_Def.rule) = [(Rule_Def.Erule, (UnparseC.term_empty, [UnparseC.term_empty]))];

     fun ne (_: Rule_Def.rule list list) (_: term) = SOME Rule_Def.Erule;

     fun fo (_: Rule_Def.rule list list) (_: term) (_: term) = [(Rule_Def.Erule, (UnparseC.term_empty, [UnparseC.term_empty]))];

 in

 val e_rfuns = Rule_Def.Rfuns {init_state = ii, normal_form = no, locate_rule = lo,

 		  next_rule = ne, attach_form = fo};

 end;

 val e_rrls =

   Rule_Def.Rrls {id = "e_rrls", prepat = [], rew_ord = ("dummy_ord", dummy_ord), erls = Rule_Def.Empty,

     calc = [], errpatts = [], scr = e_rfuns}

 (*\------- this will disappear eventually -----------/*)

 (**)end(**)