(* Title:  Specify/i-model.sml

   Author: Walther Neuper 110226

   (c) due to copyright terms

\<open>I_Model\<close> serves students' interactive modelling and gives feedback in the specify-phase.

*)

signature INTERACTION_MODEL =

sig

  type T

  type T_TEST

  val OLD_to_TEST: T -> T_TEST

  val TEST_to_OLD: T_TEST -> T

  val empty: T

  val empty_TEST: T_TEST

  type single

  type single_TEST

  val empty_single: single

  val empty_single_TEST: single_TEST

  val is_empty_single_TEST: single_TEST -> bool

  type variant

  type variants

  type m_field

  type descriptor

  datatype feedback = datatype Model_Def.i_model_feedback

  datatype feedback_TEST = datatype Model_Def.i_model_feedback_TEST

  val feedback_empty_TEST: Model_Def.i_model_feedback_TEST

  type env

  type message

  val single_to_string: Proof.context -> single -> string

  val single_to_string_TEST: Proof.context -> single_TEST -> string

  val to_string: Proof.context -> T -> string

  val to_string_TEST: Proof.context -> T_TEST -> string

  val feedback_OLD_to_TEST: feedback -> feedback_TEST

  datatype add_single = Add of single | Err of string

  val init: Model_Pattern.T -> T

  val init_TEST: O_Model.T -> Model_Pattern.T -> T_TEST

  val check_single: Proof.context -> m_field -> O_Model.T -> T -> Model_Pattern.T ->

    TermC.as_string -> add_single

  val add_single: theory -> single -> T -> T

  val make_tactic: m_field -> TermC.as_string * T -> Tactic.T

  val descriptor: feedback -> descriptor

  val descriptor_TEST: feedback_TEST -> descriptor

  val descr_pairs_to_string: Proof.context -> (Model_Pattern.single * single_TEST) list -> string

  val o_model_values: feedback -> O_Model.values

  val variables: Model_Pattern.T -> Model_Def.i_model_TEST -> term list

  val is_notyet_input : Proof.context -> T -> O_Model.values -> O_Model.single -> Model_Pattern.T

    -> message * single

  val get_field_term: theory -> O_Model.single -> single -> m_field * TermC.as_string

  val add: single -> T -> T

  val add_other: variant -> T_TEST -> single_TEST -> single_TEST

  val fill_method: O_Model.T -> T_TEST * T_TEST-> Model_Pattern.T -> T_TEST

  val s_make_complete: Proof.context ->  O_Model.T -> T_TEST * T_TEST -> Problem.id * MethodC.id ->

    T_TEST * T_TEST

  val s_are_complete: Proof.context -> O_Model.T -> T_TEST * T_TEST -> Problem.id * MethodC.id -> bool

  val is_error: feedback -> bool

  val to_p_model: theory -> feedback -> string

(*/----- from isac_test for Minisubpbl*)

  val msg: variants -> feedback_TEST -> string

  val transfer_terms: O_Model.single -> single_TEST

  val eq1: ''a -> 'b * (''a * 'c) -> bool

  val feedback_to_string: Proof.context -> feedback -> string

  val feedback_TEST_to_string: Proof.context -> feedback_TEST -> string

  val ori_2itm: feedback -> term -> term list -> 'a * 'b * string * descriptor * term list -> 

    'a * 'b * bool * string * feedback

  val seek_ppc: int -> T -> single option

  val overwrite_ppc: theory -> single -> T -> T

(*\----- from isac_test for Minisubpbl*)

\<^isac_test>\<open>

  (**)

\<close>

end

(**)

structure I_Model(**) : INTERACTION_MODEL(**) =

struct

(**)

(** data types **)

type variant =  Model_Def.variant;

type variants =  Model_Def.variants;

type m_field = Model_Def.m_field;

type descriptor = Model_Def.descriptor;

type T = Model_Def.i_model_single list;

(* for developing input from PIDE, we use T_TEST with these ideas:

  (1) the new structure is as close to old T, because we want to preserve the old tests

  (2) after development (with *_TEST) of essential parts of the Specification's semantics,

      we adapt the old tests to the new T_TEST

  (3) together with adaption of the tests we remove the *_TEST

*)

type T_TEST = Model_Def.i_model_single_TEST list;

datatype feedback = datatype Model_Def.i_model_feedback;

datatype feedback_TEST = datatype Model_Def.i_model_feedback_TEST;

val feedback_empty_TEST = Model_Def.feedback_empty_TEST

type single = Model_Def.i_model_single;

type single_TEST = Model_Def.i_model_single_TEST;

val empty_single = Model_Def.i_model_empty;

val empty_single_TEST = Model_Def.i_model_empty_TEST;

fun is_empty_single_TEST (0, [], false, "i_model_empty", _) = true

  | is_empty_single_TEST _ = false

val empty = []: T;

val empty_TEST = []: T_TEST;

type env = Env.T

fun feedback_OLD_to_TEST (Cor ((d, ts), _)) = (Model_Def.Cor_TEST (d, ts))

  | feedback_OLD_to_TEST (Syn c) = (Model_Def.Syn_TEST c)

  | feedback_OLD_to_TEST (Typ c) = (Model_Def.Syn_TEST c)

  | feedback_OLD_to_TEST (Inc ((d, ts), _)) = (Model_Def.Inc_TEST (d, ts))

  | feedback_OLD_to_TEST (Sup (d, ts)) = (Model_Def.Sup_TEST (d, ts))

  | feedback_OLD_to_TEST (Mis (d, pid)) = Model_Def.Syn_TEST ((UnparseC.term (ContextC.for_ERROR ()) d) ^ " " ^

      (UnparseC.term (ContextC.for_ERROR ()) pid))

  | feedback_OLD_to_TEST (Par s) = (Model_Def.Syn_TEST s)

fun OLD_to_TEST i_old =

  map (fn (a, b, c, d, e) => (a, b, c, d, (feedback_OLD_to_TEST e, Position.none))) i_old

fun feedback_TEST_to_OLD (Model_Def.Cor_TEST (d, ts)) = (Cor ((d, ts), (TermC.empty, [])))

  | feedback_TEST_to_OLD (Model_Def.Syn_TEST c) = (Syn c)

  | feedback_TEST_to_OLD (Model_Def.Inc_TEST (d, ts)) = (Inc ((d, ts), (TermC.empty, [])))

  | feedback_TEST_to_OLD (Model_Def.Sup_TEST (d, ts)) = (Sup (d, ts))

fun TEST_to_OLD i_model = 

  map (fn (a, b, c, d, (e, _)) => (a, b, c, d, feedback_TEST_to_OLD e)) i_model

type message = string;

fun feedback_to_string ctxt (Cor ((d, ts), _)) = 

    "Cor " ^ UnparseC.term  ctxt (Input_Descript.join (d, ts)) ^ " , pen2str"

  | feedback_to_string _ (Syn c) = "Syn " ^ c

  | feedback_to_string _ (Typ c) = "Typ " ^ c

  | feedback_to_string ctxt (Inc ((d, ts), _)) = 

    "Inc " ^ UnparseC.term  ctxt (Input_Descript.join (d, ts)) ^ " , pen2str"

  | feedback_to_string ctxt (Sup (d, ts)) = 

    "Sup " ^ UnparseC.term  ctxt (Input_Descript.join (d, ts))

  | feedback_to_string ctxt (Mis (d, pid)) = 

    "Mis " ^ UnparseC.term  ctxt d ^ " " ^ UnparseC.term ctxt pid

  | feedback_to_string _ (Par s) = "Trm "^s;

(**)

fun feedback_TEST_to_string ctxt (Cor_TEST (d, ts)) = 

    "Cor_TEST " ^ UnparseC.term ctxt (Input_Descript.join (d, ts)) ^ " , pen2str"

  | feedback_TEST_to_string _ (Syn_TEST c) =

    "Syn_TEST " ^ c

  | feedback_TEST_to_string ctxt (Inc_TEST (d, [])) = 

    "Inc_TEST " ^ UnparseC.term ctxt (Input_Descript.join (d, [])) ^ " " ^ 

      Model_Pattern.empty_for d

  | feedback_TEST_to_string ctxt (Inc_TEST (d, ts)) =

    "Inc_TEST " ^ UnparseC.term ctxt (Input_Descript.join (d, ts)) ^ " , pen2str"

  | feedback_TEST_to_string ctxt (Sup_TEST (d, ts)) = 

    "Sup_TEST " ^ UnparseC.term ctxt (Input_Descript.join (d, ts))

fun single_to_string ctxt (i, is, b, s, itm_) = 

  "(" ^ string_of_int i ^ " ," ^ ints2str' is ^ " ," ^ bool2str b ^ " ," ^

  s ^ " ," ^ feedback_to_string ctxt itm_ ^ ")";

fun single_to_string_TEST ctxt (i, is, b, s, (itm_, _(*Position.T*))) = 

  "(" ^ string_of_int i ^ ", " ^ ints2str' is ^ ", " ^ bool2str b ^ " ," ^

  s ^ ", (" ^ feedback_TEST_to_string ctxt itm_ ^ ", Position.T))";

fun to_string ctxt itms = strs2str' (map (linefeed o (single_to_string ctxt)) itms);

fun to_string_TEST ctxt itms = strs2str' (map (linefeed o (single_to_string_TEST ctxt)) itms);

(** make a Tactic.T **)

fun make_tactic m_field (term_as_string, i_model) =

  case m_field of

    "#Given" => Tactic.Add_Given' (term_as_string, i_model)

  | "#Find" => Tactic.Add_Find' (term_as_string, i_model)

  | "#Relate" => Tactic.Add_Relation'(term_as_string, i_model)

  | str => raise ERROR ("specify_additem Frm, Pbl: uncovered case with " ^ str);

(** initialise a model **)

fun init pbt = 

  let

    fun pbt2itm (f, (d, _)) = (0, [], false, f, Inc ((d, []), (TermC.empty, [])))

  in map pbt2itm pbt end

(*

  Design decision:

* Now the Model in Specification is intialised such that the placement of items can be

  maximally stable during interactive input to the Specification.

* Template.show provides the initial output to the user and thus determines what will be parsed

  by Outer_Syntax later during interaction.

* The relation between O_Model.T and I_Model.T becomes much simpler.

*)

(**)

fun pat_to_item o_model (_, (descriptor, _)) =

  case find_first (fn (_, _, _, desc, _) => desc = descriptor) o_model of

    NONE => raise ERROR "I_Model.pat_to_item_TEST with NONE"

  | SOME (_, variants, m_field, descr, _) => (variants, false, m_field,

    (Inc_TEST (descr, []), Position.none))

fun init_TEST o_model model_patt =

  let

    val pre_items = map (pat_to_item o_model) model_patt

  in

    O_Model.add_enumerate pre_items |> map (fn (a, (b, c, d, e)) => (a, b, c, d, e))

  end

fun o_model_values (Cor ((_, ts), _)) = ts

  | o_model_values (Syn _) = []

  | o_model_values (Typ _) = []

  | o_model_values (Inc ((_, ts), _)) = ts

  | o_model_values (Sup (_, ts)) = ts

  | o_model_values (Mis _) = []

  | o_model_values _ = raise ERROR "o_model_values: uncovered case in fun.def.";

val unique = Syntax.read_term\<^context> "UnIqE_tErM";

fun descriptor (Cor ((d ,_), _)) = d

  | descriptor (Syn _) = ((*tracing ("*** descriptor: Syn ("^c^")");*) unique)

  | descriptor (Typ _) = ((*tracing ("*** descriptor: Typ ("^c^")");*) unique)

  | descriptor (Inc ((d, _), _)) = d

  | descriptor (Sup (d, _)) = d

  | descriptor (Mis (d, _)) = d

  | descriptor _ = raise ERROR "descriptor: uncovered case in fun.def.";

fun descriptor_TEST (Cor_TEST (d ,_)) = d

  | descriptor_TEST (Syn_TEST _) = ((*tracing ("*** descriptor: Syn ("^c^")");*) unique)

  | descriptor_TEST (Inc_TEST (d, _)) = d

  | descriptor_TEST (Sup_TEST (d, _)) = d

fun descr_pairs_to_string ctxt equal_descr_pairs =

(map (fn (a, b) => pair (Model_Pattern.pat2str ctxt a) (single_to_string_TEST ctxt b)

    |> pair2str) equal_descr_pairs)

  |> strs2str'

fun variables model_patt i_model =

  Pre_Conds.environment_TEST model_patt i_model

  |> map snd

val unknown_descriptor = Syntax.read_term\<^context> "unknown::'a => unknow";

(* get a term from O_Model, notyet input in I_Model.

   the term from O_Model is thrown back to a string in order to reuse

   machinery for immediate input by the user. *)

fun get_field_term thy (_, _, _, d, ts) (_, _, _, fd, itm_) =

  (fd, ((UnparseC.term_in_thy thy) o Input_Descript.join) (d, subtract op = (o_model_values itm_) ts))

(*update the itm_ already input, all..from ori*)

fun ori_2itm itm_ pid all (id, vt, fd, d, ts) = 

  let 

    val ts' = union op = (o_model_values itm_) ts;

    val pval = [Input_Descript.join'''' (d, ts')]

	  (*WN.9.5.03: FIXXXME [#0, epsilon] here would upd_penv be called for [#0, epsilon] etc*)

    val complete = if eq_set op = (ts', all) then true else false

  in

    case itm_ of

      (Cor _) => 

        (if fd = "#undef" then (id, vt, complete, fd, Sup (d, ts')) 

	       else (id, vt, complete, fd, Cor ((d, ts'), (pid, pval))))

    | (Syn c) => raise ERROR ("ori_2itm wants to overwrite " ^ c)

    | (Typ c) => raise ERROR ("ori_2itm wants to overwrite " ^ c)

    | (Inc _) =>

      if complete

  	  then (id, vt, true, fd, Cor ((d, ts'), (pid, pval)))

  	  else (id, vt, false, fd, Inc ((d, ts'), (pid, pval)))

    | (Sup (d,ts')) => (*4.9.01 lost env*)

  	  (*if fd = "#undef" then*) (id,vt,complete,fd,Sup(d,ts'))

  	  (*else (id,vt,complete,fd,Cor((d,ts'),e))*)

      (* 28.1.00: not completely clear ---^^^ etc.*)

    | (Mis _) => (* 4.9.01: Mis just copied *)

       if complete

  		 then (id, vt, true, fd, Cor ((d,ts'), (pid, pval)))

  		 else (id, vt, false, fd, Inc ((d,ts'), (pid, pval)))

    | i => raise ERROR ("ori_2itm: uncovered case of " ^ feedback_to_string (ContextC.for_ERROR ()) i)

  end

(** find next step **)

fun eq1 d (_, (d', _)) = (d = d')

fun eq3 f d (_, _, _, f', itm_) = f = f' andalso d = (descriptor itm_) 

fun is_notyet_input ctxt itms all (i, v, f, d, ts) pbt =

  case find_first (eq1 d) pbt of

    SOME (_, (_, pid)) =>

      (case find_first (eq3 f d) itms of

        SOME (_, _, _, _, itm_) =>

          let val ts' = inter op = (o_model_values itm_) ts

          in 

            if subset op = (ts, ts') 

            then (((strs2str' o map (UnparseC.term ctxt)) ts') ^ " already input", empty_single)

	          else ("", ori_2itm itm_ pid all (i, v, f, d, subtract op = ts' ts))

	          end

	    | NONE => ("", ori_2itm (Inc ((TermC.empty, []), (pid, []))) pid all (i, v, f, d, ts)))

  | NONE => ("", ori_2itm (Sup (d, ts)) TermC.empty all (i, v, f, d, ts))

datatype add_single =

	Add of single   (* return-value of check_single *)

| Err of string   (* error-message                *)

(*

  Create feedback for input of TermC.as_string to m_field;

  check w.r.t. O_Model.T and Model_Pattern.T.

  In case of O_Model.T = [] (i.e. no data for user-guidance in Formalise.T)

  check_single is extremely permissive.

*)

(*will come directly from PIDE -----------------vvvvvvvvvvv

  in case t comes from Step.specify_do_next -----------vvv = Position.none*)

fun check_single ctxt m_field [] i_model m_patt (ct(*, pos*)) =

    let

      val i = 1 + (if i_model = [] then 0 else map #1 i_model |> maxl)

    (*/------------ replace by ParseC.term_position -----------\*)

      val t = Syntax.read_term ctxt ct

        handle ERROR msg => error (msg (*^ Position.here pos*))

    (*\------------ replace by ParseC.term_position -----------/*)

        (*NONE => Add (i, [], false, m_field, Syn ct)*)

      val (d, ts) = Input_Descript.split t

    in 

      if d = TermC.empty then

        Add (i, [], false, m_field, Mis (unknown_descriptor, hd ts)) 

      else

        (case find_first (eq1 d) m_patt of

          NONE => Add (i, [], true, m_field, Sup (d,ts))

        | SOME (f, (_, id)) =>

            let

              fun eq2 d (i, _, _, _, itm_) = d = (descriptor itm_) andalso i <> 0

            in

              case find_first (eq2 d) i_model of

                NONE => Add (i, [], true, f,Cor ((d, ts), (id, [Input_Descript.join'''' (d, ts)])))

              | SOME (i', _, _, _, itm_) => 

                  if Input_Descript.for_list d then 

                    let

                      val in_itm = o_model_values itm_

                      val ts' = union op = ts in_itm

                      val i'' = if in_itm = [] then i else i'

                    in Add (i'', [], true, f, Cor ((d, ts'), (id, [Input_Descript.join'''' (d, ts')])))end

                  else Add (i', [], true, f, Cor ((d, ts), (id, [Input_Descript.join'''' (d, ts)])))

            end)

    end

    (*will come directly from PIDE ----------------------vvvvvvvvvvv*)

  | check_single ctxt m_field o_model i_model m_patt (str(*, pos*)) =

    let

      val (t as (descriptor $ _)) = Syntax.read_term ctxt str

        handle ERROR msg => error (msg (*TODO: ^ Position.here pp*))

        (*old code: NONE => Err ("ERROR I_Model.check_single: syntax error in \"" ^ str ^ "\"")*)

    in 

        case Model_Pattern.get_field descriptor m_patt of

          NONE => Err ("ERROR I_Model.check_single: unknown descriptor \"" ^

            UnparseC.term ctxt descriptor ^ "\"")

        | SOME m_field' => 

          if m_field <> m_field' then

            Err ("ERROR I_Model.check_single: \"" ^ UnparseC.term ctxt t ^ "\"" ^

             "\" not for field \"" ^ m_field ^ "\"")

          else

            case O_Model.contains ctxt m_field o_model t of

              ("", ori', all) => 

                (case is_notyet_input ctxt i_model all ori' m_patt of

                   ("", itm) => Add itm

                 | (msg, _) => Err ("ERROR I_Model.check_single: is_notyet_input: " ^ msg))

            | (msg, _, _) => Err ("ERROR I_Model.check_single: contains: " ^ msg)

    end

(** add input **)

fun overwrite_ppc thy itm model =

  let 

    fun repl _ (_, _, _, _, itm_) [] =

        raise ERROR ("overwrite_ppc: " ^ feedback_to_string (Proof_Context.init_global thy) itm_

          ^ " not found")

      | repl model' itm (p :: model) =

	      if (#1 itm) = (#1 p)

	      then model' @ [itm] @ model

	      else repl (model' @ [p]) itm model

  in repl [] itm model end

(*find_first item with #1 equal to id*)

fun seek_ppc _ [] = NONE

  | seek_ppc id (p :: model) = if id = #1 (p: single) then SOME p else seek_ppc id model

(* 10.3.00: insert the already compiled itm into model;

   ev. filter_out  untouched (in FE: (0,...)) item related to insert-item *)

fun add_single thy itm model =

  let 

    fun eq_untouched d (0, _, _, _, itm_) = (d = descriptor itm_)

      | eq_untouched _ _ = false

    val model' = case seek_ppc (#1 itm) model of

      SOME _ => overwrite_ppc thy itm model (*itm updated in is_notyet_input WN.11.03*)

    | NONE => (model @ [itm])

  in filter_out (eq_untouched ((descriptor o #5) itm)) model' end

(** complete I_Model.T **)

fun s_are_complete _ _ ([], _) _ = false

  | s_are_complete _ _ (_, []) _ = false

  | s_are_complete ctxt o_model (pbl_imod, met_imod) (pbl_id, met_id) =

  let

    val pbl_max_vnts = Model_Def.max_variants o_model pbl_imod

    val met_max_vnts = Model_Def.max_variants o_model met_imod

    val max_vnts = inter op= pbl_max_vnts met_max_vnts

    val max_vnt = if max_vnts = []

      then raise ERROR "I_Model.s_are_complete: request user to review met_imod"

      else hd max_vnts

    val (pbl_imod', met_imod') = (

      filter (fn (_, vnts, _, _, _) => member_swap op = max_vnt vnts) pbl_imod,

      filter (fn (_, vnts, _, _, _) => member_swap op = max_vnt vnts) met_imod)

    val (pbl_check, _) = Pre_Conds.check_internal ctxt pbl_imod' (Pos.Pbl, pbl_id)

    val (met_check, _) = Pre_Conds.check_internal ctxt met_imod' (Pos.Met, met_id)

  in

    pbl_check andalso met_check

  end

fun is_error (Cor _) = false

  | is_error (Sup _) = false

  | is_error (Inc _) = false

  | is_error (Mis _) = false

  | is_error _ = true

(*create output-string for itm*)

fun to_p_model thy (Cor ((d, ts), _)) = UnparseC.term_in_thy thy (Input_Descript.join (d, ts))

  | to_p_model _ (Syn c) = c

  | to_p_model _ (Typ c) = c

  | to_p_model thy (Inc ((d, ts), _)) = UnparseC.term_in_thy thy (Input_Descript.join (d, ts))

  | to_p_model thy (Sup (d, ts)) = UnparseC.term_in_thy thy (Input_Descript.join (d, ts))

  | to_p_model thy (Mis (d, pid)) = UnparseC.term_in_thy thy d ^ " " ^ UnparseC.term_in_thy thy pid

  | to_p_model _ _ = raise ERROR "to_p_model: uncovered definition"

fun eq_dsc ((_, _, _, _, itm_), (_, _, _, _, iitm_)) = (descriptor itm_ = descriptor iitm_)

(* insert_ppc = add for appl_add', input_icalhd 11.03,

   handles superfluous items carelessly                       *)

fun add itm itms = if member eq_dsc itms itm then itms else itms @ [itm] (* @ new itm *)

(*

  in case there is an item in i2_model(= met) with Sup_TEST, 

  find_first an appropriate (variant, descriptor) item in i1_model(= pbl) and add it instead Sup_TEST,

  otherwise keep the items of i2_model.

*)

fun add_other max_vnt i1_model (i2, _, bool2, m_field2, (Sup_TEST (descr2, ts2), pos2)) =

    (case find_first (fn (_, vnts1, _, _, (feedb1, _)) => case Pre_Conds.get_dscr' feedb1 of

          NONE => false

        | SOME descr1 => descr1 = descr2 andalso Model_Def.member_vnt vnts1 max_vnt) i1_model of

      NONE =>

        (i2, [max_vnt], bool2, m_field2, (Sup_TEST (descr2, ts2), pos2)) (*the present in i2_model*)

    | SOME i1_single => i1_single)                      (*shift the item from i1_model to i2_model*)

  | add_other _ _ i2_single = i2_single                     (*keep all the other items in i2_model*)

fun fill_method o_model (pbl_imod, met_imod) met_patt =

  let

    val pbl_max_vnts = Model_Def.max_variants o_model pbl_imod

    (*probably pbl/met_imod = [], so take met_patt; if empty return Sup*)

    val i_from_met = map (fn (_, (descr, _)) => (*order from met_patt*)

      Pre_Conds.get_descr_vnt descr pbl_max_vnts met_imod) met_patt (*\<longrightarrow> right order for args*)

    val met_max_vnts = Model_Def.max_variants o_model i_from_met;

    val max_vnt = hd (inter op= pbl_max_vnts met_max_vnts);

    (*add items from pbl_imod (without overwriting existing items in met_imod)*)

  in

    map (add_other max_vnt pbl_imod) i_from_met

  end 

fun msg vnts feedb = "get_descr_vnt' returns NONE: i.e. it does not find an item of o_model with\n" ^

  "variants " ^ ints2str' vnts ^ " and descriptor " ^

  (feedb |> Pre_Conds.get_dscr' |> the |> UnparseC.term (ContextC.for_ERROR ()))

fun transfer_terms (i, vnts, m_field, descr, ts) =

  (i, vnts, true, m_field, (Cor_TEST (descr, ts), Position.none))

fun s_make_complete ctxt o_model (pbl_imod, met_imod) (pbl_id, met_id) =

  let

    val {model = pbl_patt, ...} = Problem.from_store ctxt pbl_id;

    val {model = met_patt, ...} = MethodC.from_store ctxt met_id;

    val pbl_max_vnts = Model_Def.max_variants o_model pbl_imod;

    val i_from_pbl = map (fn (_, (descr, _)) =>

      Pre_Conds.get_descr_vnt descr pbl_max_vnts pbl_imod) pbl_patt

    val pbl_from_o_model = map ((fn i_single as (_, _, _, _, (feedb, _)) =>

      if is_empty_single_TEST i_single

      then

        case Pre_Conds.get_descr_vnt' feedb pbl_max_vnts o_model of

            [] => raise ERROR (msg pbl_max_vnts feedb)

          | o_singles => map transfer_terms o_singles

      else [i_single (*fetched before from pbl_imod*)])) i_from_pbl |> flat

    val i_from_met = map (fn (_, (descr, _)) =>

      Pre_Conds.get_descr_vnt descr pbl_max_vnts met_imod) met_patt

    val met_max_vnts = Model_Def.max_variants o_model i_from_met;

    val max_vnt = hd met_max_vnts (*need only one for solve-phase*)

    val met_from_pbl = map ((fn i_single as (_, _, _, _, (feedb, _)) =>

      if is_empty_single_TEST i_single

      then

        case Pre_Conds.get_descr_vnt' feedb [max_vnt] o_model of

            [] => raise ERROR (msg [max_vnt] feedb)

          | o_singles => map transfer_terms o_singles

      else [i_single (*fetched before from met_imod*)])) i_from_met |> flat

  in

    (filter (fn (_, vnts', _, _, _) => member op = vnts' max_vnt) pbl_from_o_model,

      met_from_pbl)

  end

(**)end(**);