(* title: Interpret/error-pattern.sml

   author: Walther Neuper

   0603

   (c) due to copyright terms

In case a term is input, which contains an "error pattern" (provided by a mathauthor),

several "fill patterns" can be presented as help for the next step.)

*)

signature ERROR_PATTERN =

sig

  type id = Error_Pattern_Def.id

  type T = Error_Pattern_Def.T

  val s_to_string : T list -> string

  val empty: T

  type fill_in_id = Error_Pattern_Def.fill_in_id

  type fill_in = Error_Pattern_Def.fill_in

  val fill_in_empty: fill_in

  type record

  val from_store: Tactic.input -> Error_Pattern_Def.id list

  val filled_exactly: Calc.T -> string -> string * Tactic.input

  val check_for: term * term -> term * Env.T -> T list * Rule_Set.T -> id option

  val find_fill_patterns: Calc.T -> id -> record list

\<^isac_test>\<open>

  val check_for': term * term -> subst -> id * term -> Rule_Set.T -> id option

  val fill_from_store: Subst.input option * Subst.T -> term -> id -> thm ->

    record list

  val fill_form: Subst.input option * Subst.T -> thm * term -> id -> fill_in ->

    record option

\<close>

end

(**)

structure Error_Pattern(**): ERROR_PATTERN(**) =

struct

(**)

type id = Error_Pattern_Def.id;

type T = Error_Pattern_Def.T;

val s_to_string = Error_Pattern_Def.s_to_string;

val empty = ("e_errpatID", [TermC.parse_patt @{theory} "?a = ?b"], [@{thm refl}])

type fill_in_id = Error_Pattern_Def.fill_in_id;

type fill_in = Error_Pattern_Def.fill_in;

val fill_in_empty = ("e_fillpatID", TermC.parse_patt @{theory} "?a = _", "e_errpatID")

type record = (fill_in_id * term * thm * Subst.input option);

(*

  check if (agreed result, input formula) matches the error pattern "pat" modulo simplifier rls

*)

fun check_for' (res, inf) subst (id, pat) rls =

  let

    val ctxt = Proof_Context.init_global ((ThyC.Isac()))

    val (res', _, _, rewritten) =

      Rewrite.rew_sub ctxt 1 subst Rewrite_Ord.function_empty

        Rule_Set.empty false [] (HOLogic.Trueprop $ pat) res;

  in

    if rewritten then 

      let

        val norm_res = case Rewrite.rewrite_set_inst_ ctxt false subst rls  res' of

            NONE => res'

          | SOME (norm_res, _) => norm_res

        val norm_inf = case Rewrite.rewrite_set_inst_ ctxt false subst rls inf of

            NONE => inf

          | SOME (norm_inf, _) => norm_inf

      in

        if norm_res = norm_inf then SOME id else NONE

      end

    else NONE

  end;

(*

  check if (agreed result, input formula) matches SOME error pattern modulo simplifier rls;

  (prog, env) for retrieval of casual substitution for bdv in the pattern.

*)

fun check_for (res, inf) (prog, env) (errpats, rls) =

  let

    val (_, subst) = Subst.for_bdv prog env

    fun scan (_, [], _) = NONE

      | scan (id, T :: errpats, _) =

          case check_for' (res, inf) subst (id, T) rls of

            NONE => scan (id, errpats, [])

          | SOME id => SOME id

    fun scans [] = NONE

      | scans (group :: groups) =

          case scan group of

            NONE => scans groups

          | SOME id => SOME id

  in scans errpats end;

(* fill-in patterns an forms.

  returns thm required by "fun in_fillform *)

fun fill_form (subs_opt, subst) (thm, form) id (fillpatID, pat, erpaID) =

  let

    val ctxt = Proof_Context.init_global ((ThyC.Isac()))

    val (form', _, _, rewritten) =

      Rewrite.rew_sub ctxt 1 subst Rewrite_Ord.function_empty Rule_Set.empty false [] (HOLogic.Trueprop $ pat) form;

  in (*the fillpat of the thm must be dedicated to id*)

    if id = erpaID andalso rewritten then

      SOME (fillpatID, HOLogic.mk_eq (form, form'), thm, subs_opt) 

    else NONE

  end

fun fill_from_store subst form id thm =

  let

    val thmDeriv = Thm.get_name_hint thm

    val (part, thyID) = Thy_Read.thy_containing_thm thmDeriv

    val theID = [part, thyID, "Theorems", ThmC.cut_id thmDeriv]

    val fillpats = case Thy_Read.from_store theID of

      Thy_Write.Hthm {fillpats, ...} => fillpats

    | _ => raise ERROR "fill_from_store: uncovered case of get_the"

    val some = map (fill_form subst (thm, form) id) fillpats

  in some |> filter is_some |> map the end

fun find_fill_patterns (pt, pos as (p, _): Pos.pos') id =

  let 

    val f_curr = Ctree.get_curr_formula (pt, pos);

    val pp = Ctree.par_pblobj pt p

    val (errpats, prog) = case MethodC.from_store (Ctree.get_obj Ctree.g_metID pt pp) of

      {errpats, scr = Rule.Prog prog, ...} => (errpats, prog)

    | _ => raise ERROR "find_fill_patterns: uncovered case of get_met"

    val {env, ...} = Ctree.get_istate_LI pt pos |> Istate.the_pstate

    val subst = Subst.for_bdv prog env

    val errpatthms = errpats

      |> filter ((curry op = id) o (#1: Error_Pattern_Def.T -> Error_Pattern_Def.id))

      |> map (#3: Error_Pattern_Def.T -> thm list)

      |> flat

  in map (fill_from_store subst f_curr id) errpatthms |> flat end

(*

  Check input on a fill-pattern:

  check if input is exactly equal to the rewrite from a rule

  which is stored at the pos where the input is stored of "ok".

*)

fun filled_exactly (pt, pos as (p, _)) istr =

  case TermC.parseNEW (ThyC.get_theory "Isac_Knowledge" |> Proof_Context.init_global) istr of

    NONE => ("syntax error in '" ^ istr ^ "'", Tactic.Tac "")

  | SOME ifo => 

      let

        val p' = Pos.lev_on p;

        val tac = Ctree.get_obj Ctree.g_tac pt p';

      in 

        case Solve_Step.check tac (pt, pos) of

          Applicable.No msg => (msg, Tactic.Tac "")

        | Applicable.Yes rew =>

            let

              val res = case rew of

               Tactic.Rewrite_Inst' (_, _, _, _, _, _, _, (res, _)) => res

              |Tactic.Rewrite' (_, _, _, _, _, _, (res, _)) => res

              | t => raise ERROR ("filled_exactly: uncovered case for " ^ Tactic.string_of t)

            in 

              if not (ifo = res) then

                ("input does not exactly fill the gaps", Tactic.Tac "")

              else ("ok", tac)

            end

      end

(* fetch errpatIDs from an arbitrary tactic *)

fun from_store tac =

  let

    val rlsID =

      case tac of

       Tactic.Rewrite_Set rlsID => rlsID

      |Tactic.Rewrite_Set_Inst (_, rlsID) => rlsID

      | _ => "empty"

    val (part, thyID) = Thy_Read.thy_containing_rls "Isac_Knowledge" rlsID;

    val rls = case Thy_Read.from_store [part, thyID, "Rulesets", rlsID] of

      Thy_Write.Hrls {thy_rls = (_, rls), ...} => rls

    | _ => raise ERROR "from_store: uncovered case of get_the"

  in case rls of

    Rule_Def.Repeat {errpatts, ...} => errpatts

  | Rule_Set.Sequence {errpatts, ...} => errpatts

  | Rule_Set.Rrls {errpatts, ...} => errpatts

  | Rule_Set.Empty => []

  end

(**)end(**)