(*  Title:      Tools/code/code_funcgr.ML

    ID:         $Id$

    Author:     Florian Haftmann, TU Muenchen

Retrieving, normalizing and structuring defining equations in graph

with explicit dependencies.

*)

signature CODE_FUNCGR =

sig

  type T

  val timing: bool ref

  val funcs: T -> string -> thm list

  val typ: T -> string -> typ

  val all: T -> string list

  val pretty: theory -> T -> Pretty.T

  val make: theory -> string list -> T

  val make_consts: theory -> string list -> string list * T

  val eval_conv: theory -> (T -> cterm -> thm) -> cterm -> thm

  val eval_term: theory -> (T -> term -> 'a) -> term -> 'a

end

structure CodeFuncgr : CODE_FUNCGR =

struct

(** the graph type **)

type T = (typ * thm list) Graph.T;

fun funcs funcgr =

  these o Option.map snd o try (Graph.get_node funcgr);

fun typ funcgr =

  fst o Graph.get_node funcgr;

fun all funcgr = Graph.keys funcgr;

fun pretty thy funcgr =

  AList.make (snd o Graph.get_node funcgr) (Graph.keys funcgr)

  |> (map o apfst) (CodeUnit.string_of_const thy)

  |> sort (string_ord o pairself fst)

  |> map (fn (s, thms) =>

       (Pretty.block o Pretty.fbreaks) (

         Pretty.str s

         :: map Display.pretty_thm thms

       ))

  |> Pretty.chunks;

(** generic combinators **)

fun fold_consts f thms =

  thms

  |> maps (op :: o swap o apfst (snd o strip_comb) o Logic.dest_equals o Thm.plain_prop_of)

  |> (fold o fold_aterms) (fn Const c => f c | _ => I);

fun consts_of (const, []) = []

  | consts_of (const, thms as _ :: _) = 

      let

        fun the_const (c, _) = if c = const then I else insert (op =) c

      in fold_consts the_const thms [] end;

fun insts_of thy algebra c ty_decl ty =

  let

    val tys_decl = Sign.const_typargs thy (c, ty_decl);

    val tys = Sign.const_typargs thy (c, ty);

    fun class_relation (x, _) _ = x;

    fun type_constructor tyco xs class =

      (tyco, class) :: maps (maps fst) xs;

    fun type_variable (TVar (_, sort)) = map (pair []) sort

      | type_variable (TFree (_, sort)) = map (pair []) sort;

    fun mk_inst ty (TVar (_, sort)) = cons (ty, sort)

      | mk_inst ty (TFree (_, sort)) = cons (ty, sort)

      | mk_inst (Type (_, tys1)) (Type (_, tys2)) = fold2 mk_inst tys1 tys2;

    fun of_sort_deriv (ty, sort) =

      Sorts.of_sort_derivation (Sign.pp thy) algebra

        { class_relation = class_relation, type_constructor = type_constructor,

          type_variable = type_variable }

        (ty, sort) handle Sorts.CLASS_ERROR _ => [] (*permissive!*)

  in

    flat (maps of_sort_deriv (fold2 mk_inst tys tys_decl []))

  end;

fun drop_classes thy tfrees thm =

  let

    val (_, thm') = Thm.varifyT' [] thm;

    val tvars = Term.add_tvars (Thm.prop_of thm') [];

    val unconstr = map (Thm.ctyp_of thy o TVar) tvars;

    val instmap = map2 (fn (v_i, _) => fn (v, sort) => pairself (Thm.ctyp_of thy)

      (TVar (v_i, []), TFree (v, sort))) tvars tfrees;

  in

    thm'

    |> fold Thm.unconstrainT unconstr

    |> Thm.instantiate (instmap, [])

    |> Tactic.rule_by_tactic ((REPEAT o CHANGED o ALLGOALS o Tactic.resolve_tac) (AxClass.class_intros thy))

  end;

(** graph algorithm **)

val timing = ref false;

local

exception CLASS_ERROR of string list * string;

fun resort_thms algebra tap_typ [] = []

  | resort_thms algebra tap_typ (thms as thm :: _) =

      let

        val thy = Thm.theory_of_thm thm;

        val pp = Sign.pp thy;

        val cs = fold_consts (insert (op =)) thms [];

        fun match_const c (ty, ty_decl) =

          let

            val tys = Sign.const_typargs thy (c, ty);

            val sorts = map (snd o dest_TVar) (Sign.const_typargs thy (c, ty_decl));

          in fn tab => fold2 (curry (Sorts.meet_sort algebra)) tys sorts tab

            handle Sorts.CLASS_ERROR e => raise CLASS_ERROR ([c], Sorts.msg_class_error pp e ^ ",\n"

              ^ "for constant " ^ CodeUnit.string_of_const thy c

              ^ "\nin defining equations(s)\n"

              ^ (cat_lines o map string_of_thm) thms)

            (*handle Sorts.CLASS_ERROR _ => tab (*permissive!*)*)

          end;

        fun match (c, ty) = case tap_typ c

           of SOME ty_decl => match_const c (ty, ty_decl)

            | NONE => I;

        val tvars = fold match cs Vartab.empty;

      in map (CodeUnit.inst_thm tvars) thms end;

fun resort_funcss thy algebra funcgr =

  let

    val typ_funcgr = try (fst o Graph.get_node funcgr);

    val resort_dep = apsnd (resort_thms algebra typ_funcgr);

    fun resort_rec tap_typ (const, []) = (true, (const, []))

      | resort_rec tap_typ (const, thms as thm :: _) =

          let

            val (_, ty) = CodeUnit.head_func thm;

            val thms' as thm' :: _ = resort_thms algebra tap_typ thms

            val (_, ty') = CodeUnit.head_func thm';

          in (Sign.typ_equiv thy (ty, ty'), (const, thms')) end;

    fun resort_recs funcss =

      let

        fun tap_typ c =

          AList.lookup (op =) funcss c

          |> these

          |> try hd

          |> Option.map (snd o CodeUnit.head_func);

        val (unchangeds, funcss') = split_list (map (resort_rec tap_typ) funcss);

        val unchanged = fold (fn x => fn y => x andalso y) unchangeds true;

      in (unchanged, funcss') end;

    fun resort_rec_until funcss =

      let

        val (unchanged, funcss') = resort_recs funcss;

      in if unchanged then funcss' else resort_rec_until funcss' end;

  in map resort_dep #> resort_rec_until end;

fun instances_of thy algebra insts =

  let

    val thy_classes = (#classes o Sorts.rep_algebra o Sign.classes_of) thy;

    fun all_classparams tyco class =

      these (try (#params o AxClass.get_info thy) class)

      |> map_filter (fn (c, _) => try (AxClass.param_of_inst thy) (c, tyco))

  in

    Symtab.empty

    |> fold (fn (tyco, class) =>

        Symtab.map_default (tyco, []) (insert (op =) class)) insts

    |> (fn tab => Symtab.fold (fn (tyco, classes) => append (maps (all_classparams tyco)

         (Graph.all_succs thy_classes classes))) tab [])

  end;

fun instances_of_consts thy algebra funcgr consts =

  let

    fun inst (cexpr as (c, ty)) = insts_of thy algebra c

      ((fst o Graph.get_node funcgr) c) ty;

  in

    []

    |> fold (fold (insert (op =)) o inst) consts

    |> instances_of thy algebra

  end;

fun ensure_const' thy algebra funcgr const auxgr =

  if can (Graph.get_node funcgr) const

    then (NONE, auxgr)

  else if can (Graph.get_node auxgr) const

    then (SOME const, auxgr)

  else if is_some (Code.get_datatype_of_constr thy const) then

    auxgr

    |> Graph.new_node (const, [])

    |> pair (SOME const)

  else let

    val thms = Code.these_funcs thy const

      |> CodeUnit.norm_args

      |> CodeUnit.norm_varnames CodeName.purify_tvar CodeName.purify_var;

    val rhs = consts_of (const, thms);

  in

    auxgr

    |> Graph.new_node (const, thms)

    |> fold_map (ensure_const thy algebra funcgr) rhs

    |-> (fn rhs' => fold (fn SOME const' => Graph.add_edge (const, const')

                           | NONE => I) rhs')

    |> pair (SOME const)

  end

and ensure_const thy algebra funcgr const =

  let

    val timeap = if !timing

      then Output.timeap_msg ("time for " ^ CodeUnit.string_of_const thy const)

      else I;

  in timeap (ensure_const' thy algebra funcgr const) end;

fun merge_funcss thy algebra raw_funcss funcgr =

  let

    val funcss = raw_funcss

      |> resort_funcss thy algebra funcgr

      |> filter_out (can (Graph.get_node funcgr) o fst);

    fun typ_func c [] = Code.default_typ thy c

      | typ_func c (thms as thm :: _) = case AxClass.inst_of_param thy c

         of SOME (c', tyco) => 

              let

                val (_, ty) = CodeUnit.head_func thm;

                val SOME class = AxClass.class_of_param thy c';

                val sorts_decl = Sorts.mg_domain algebra tyco [class];

                val tys = Sign.const_typargs thy (c, ty);

                val sorts = map (snd o dest_TVar) tys;

              in if sorts = sorts_decl then ty

                else raise CLASS_ERROR ([c], "Illegal instantation for class operation "

                  ^ CodeUnit.string_of_const thy c

                  ^ "\nin defining equations\n"

                  ^ (cat_lines o map (string_of_thm o AxClass.overload thy)) thms)

              end

          | NONE => (snd o CodeUnit.head_func) thm;

    fun add_funcs (const, thms) =

      Graph.new_node (const, (typ_func const thms, thms));

    fun add_deps (funcs as (const, thms)) funcgr =

      let

        val deps = consts_of funcs;

        val insts = instances_of_consts thy algebra funcgr

          (fold_consts (insert (op =)) thms []);

      in

        funcgr

        |> ensure_consts' thy algebra insts

        |> fold (curry Graph.add_edge const) deps

        |> fold (curry Graph.add_edge const) insts

       end;

  in

    funcgr

    |> fold add_funcs funcss

    |> fold add_deps funcss

  end

and ensure_consts' thy algebra cs funcgr =

  let

    val auxgr = Graph.empty

      |> fold (snd oo ensure_const thy algebra funcgr) cs;

  in

    funcgr

    |> fold (merge_funcss thy algebra)

         (map (AList.make (Graph.get_node auxgr))

         (rev (Graph.strong_conn auxgr)))

  end handle CLASS_ERROR (cs', msg)

    => raise CLASS_ERROR (fold (insert (op =)) cs' cs, msg);

in

(** retrieval interfaces **)

fun ensure_consts thy algebra consts funcgr =

  ensure_consts' thy algebra consts funcgr

    handle CLASS_ERROR (cs', msg) => error (msg ^ ",\nwhile preprocessing equations for constant(s) "

    ^ commas (map (CodeUnit.string_of_const thy) cs'));

fun check_consts thy consts funcgr =

  let

    val algebra = Code.coregular_algebra thy;

    fun try_const const funcgr =

      (SOME const, ensure_consts' thy algebra [const] funcgr)

      handle CLASS_ERROR (cs', msg) => (NONE, funcgr);

    val (consts', funcgr') = fold_map try_const consts funcgr;

  in (map_filter I consts', funcgr') end;

fun raw_eval thy f ct funcgr =

  let

    val algebra = Code.coregular_algebra thy;

    fun consts_of ct = fold_aterms (fn Const c_ty => cons c_ty | _ => I)

      (Thm.term_of ct) [];

    val _ = Sign.no_vars (Sign.pp thy) (Thm.term_of ct);

    val _ = Term.fold_types (Type.no_tvars #> K I) (Thm.term_of ct) ();

    val thm1 = Code.preprocess_conv ct;

    val ct' = Thm.rhs_of thm1;

    val cs = map fst (consts_of ct');

    val funcgr' = ensure_consts thy algebra cs funcgr;

    val (_, thm2) = Thm.varifyT' [] thm1;

    val thm3 = Thm.reflexive (Thm.rhs_of thm2);

    val [thm4] = resort_thms algebra (try (fst o Graph.get_node funcgr')) [thm3]

      handle CLASS_ERROR (_, msg) => error msg;

    val tfrees = Term.add_tfrees (Thm.prop_of thm1) [];

    fun inst thm =

      let

        val tvars = Term.add_tvars (Thm.prop_of thm) [];

        val instmap = map2 (fn (v_i, sort) => fn (v, _) => pairself (Thm.ctyp_of thy)

          (TVar (v_i, sort), TFree (v, sort))) tvars tfrees;

      in Thm.instantiate (instmap, []) thm end;

    val thm5 = inst thm2;

    val thm6 = inst thm4;

    val ct'' = Thm.rhs_of thm6;

    val c_exprs = consts_of ct'';

    val drop = drop_classes thy tfrees;

    val instdefs = instances_of_consts thy algebra funcgr' c_exprs;

    val funcgr'' = ensure_consts thy algebra instdefs funcgr';

  in (f drop thm5 funcgr'' ct'', funcgr'') end;

fun raw_eval_conv thy conv =

  let

    fun conv' drop_classes thm1 funcgr ct =

      let

        val thm2 = conv funcgr ct;

        val thm3 = Code.postprocess_conv (Thm.rhs_of thm2);

        val thm23 = drop_classes (Thm.transitive thm2 thm3);

      in

        Thm.transitive thm1 thm23 handle THM _ =>

          error ("could not construct proof:\n"

          ^ (cat_lines o map string_of_thm) [thm1, thm2, thm3])

      end;

  in raw_eval thy conv' end;

fun raw_eval_term thy f t =

  let

    fun f' _ _ funcgr ct = f funcgr (Thm.term_of ct);

  in raw_eval thy f' (Thm.cterm_of thy t) end;

end; (*local*)

structure Funcgr = CodeDataFun

(

  type T = T;

  val empty = Graph.empty;

  fun merge _ _ = Graph.empty;

  fun purge _ NONE _ = Graph.empty

    | purge _ (SOME cs) funcgr =

        Graph.del_nodes ((Graph.all_preds funcgr 

          o filter (can (Graph.get_node funcgr))) cs) funcgr;

);

fun make thy =

  Funcgr.change thy o ensure_consts thy (Code.coregular_algebra thy);

fun make_consts thy =

  Funcgr.change_yield thy o check_consts thy;

fun eval_conv thy f =

  fst o Funcgr.change_yield thy o raw_eval_conv thy f;

fun eval_term thy f =

  fst o Funcgr.change_yield thy o raw_eval_term thy f;

end; (*struct*)