(*  Title:      Pure/codegen.ML

     ID:         $Id$

     Author:     Stefan Berghofer, TU Muenchen

     License:    GPL (GNU GENERAL PUBLIC LICENSE)

 Generic code generator.

 *)

 signature CODEGEN =

 sig

   val quiet_mode : bool ref

   val message : string -> unit

   val mode : string list ref

   val margin : int ref

   datatype 'a mixfix =

       Arg

     | Ignore

     | Pretty of Pretty.T

     | Quote of 'a;

   type 'a codegen

   val add_codegen: string -> term codegen -> theory -> theory

   val add_tycodegen: string -> typ codegen -> theory -> theory

   val add_attribute: string -> (Args.T list -> theory attribute * Args.T list) -> theory -> theory

   val print_codegens: theory -> unit

   val generate_code: theory -> (string * string) list -> string

   val generate_code_i: theory -> (string * term) list -> string

   val assoc_consts: (xstring * string option * term mixfix list) list -> theory -> theory

   val assoc_consts_i: (xstring * typ option * term mixfix list) list -> theory -> theory

   val assoc_types: (xstring * typ mixfix list) list -> theory -> theory

   val get_assoc_code: theory -> string -> typ -> term mixfix list option

   val get_assoc_type: theory -> string -> typ mixfix list option

   val invoke_codegen: theory -> string -> bool ->

     (exn option * string) Graph.T * term -> (exn option * string) Graph.T * Pretty.T

   val invoke_tycodegen: theory -> string -> bool ->

     (exn option * string) Graph.T * typ -> (exn option * string) Graph.T * Pretty.T

   val mk_const_id: Sign.sg -> string -> string

   val mk_type_id: Sign.sg -> string -> string

   val rename_term: term -> term

   val get_defn: theory -> string -> typ -> ((term list * term) * int option) option

   val is_instance: theory -> typ -> typ -> bool

   val parens: Pretty.T -> Pretty.T

   val mk_app: bool -> Pretty.T -> Pretty.T list -> Pretty.T

   val eta_expand: term -> term list -> int -> term

   val strip_tname: string -> string

   val mk_type: bool -> typ -> Pretty.T

   val mk_term_of: Sign.sg -> bool -> typ -> Pretty.T

   val mk_gen: Sign.sg -> bool -> string list -> string -> typ -> Pretty.T

   val test_fn: (int -> (string * term) list option) ref

   val test_term: theory -> int -> int -> term -> (string * term) list option

   val parse_mixfix: (string -> 'a) -> string -> 'a mixfix list

   val parsers: OuterSyntax.parser list

   val setup: (theory -> theory) list

 end;

 structure Codegen : CODEGEN =

 struct

 val quiet_mode = ref true;

 fun message s = if !quiet_mode then () else writeln s;

 val mode = ref ([] : string list);

 val margin = ref 80;

 (**** Mixfix syntax ****)

 datatype 'a mixfix =

     Arg

   | Ignore

   | Pretty of Pretty.T

   | Quote of 'a;

 fun is_arg Arg = true

   | is_arg Ignore = true

   | is_arg _ = false;

 fun quotes_of [] = []

   | quotes_of (Quote q :: ms) = q :: quotes_of ms

   | quotes_of (_ :: ms) = quotes_of ms;

 fun args_of [] xs = ([], xs)

   | args_of (Arg :: ms) (x :: xs) = apfst (cons x) (args_of ms xs)

   | args_of (Ignore :: ms) (_ :: xs) = args_of ms xs

   | args_of (_ :: ms) xs = args_of ms xs;

 fun num_args x = length (filter is_arg x);

 (**** theory data ****)

 (* type of code generators *)

 type 'a codegen = theory -> (exn option * string) Graph.T ->

   string -> bool -> 'a -> ((exn option * string) Graph.T * Pretty.T) option;

 (* parameters for random testing *)

 type test_params =

   {size: int, iterations: int, default_type: typ option};

 fun merge_test_params

   {size = size1, iterations = iterations1, default_type = default_type1}

   {size = size2, iterations = iterations2, default_type = default_type2} =

   {size = Int.max (size1, size2),

    iterations = Int.max (iterations1, iterations2),

    default_type = case default_type1 of

        None => default_type2

      | _ => default_type1};

 val default_test_params : test_params =

   {size = 10, iterations = 100, default_type = None};

 fun set_size size ({iterations, default_type, ...} : test_params) =

   {size = size, iterations = iterations, default_type = default_type};

 fun set_iterations iterations ({size, default_type, ...} : test_params) =

   {size = size, iterations = iterations, default_type = default_type};

 fun set_default_type s sg ({size, iterations, ...} : test_params) =

   {size = size, iterations = iterations,

    default_type = Some (typ_of (read_ctyp sg s))};

 (* data kind 'Pure/codegen' *)

 structure CodegenArgs =

 struct

   val name = "Pure/codegen";

   type T =

     {codegens : (string * term codegen) list,

      tycodegens : (string * typ codegen) list,

      consts : ((string * typ) * term mixfix list) list,

      types : (string * typ mixfix list) list,

      attrs: (string * (Args.T list -> theory attribute * Args.T list)) list,

      test_params: test_params};

   val empty =

     {codegens = [], tycodegens = [], consts = [], types = [], attrs = [],

      test_params = default_test_params};

   val copy = I;

   val prep_ext = I;

   fun merge

     ({codegens = codegens1, tycodegens = tycodegens1,

       consts = consts1, types = types1, attrs = attrs1,

       test_params = test_params1},

      {codegens = codegens2, tycodegens = tycodegens2,

       consts = consts2, types = types2, attrs = attrs2,

       test_params = test_params2}) =

     {codegens = rev (merge_alists (rev codegens1) (rev codegens2)),

      tycodegens = rev (merge_alists (rev tycodegens1) (rev tycodegens2)),

      consts = merge_alists consts1 consts2,

      types = merge_alists types1 types2,

      attrs = merge_alists attrs1 attrs2,

      test_params = merge_test_params test_params1 test_params2};

   fun print sg ({codegens, tycodegens, ...} : T) =

     Pretty.writeln (Pretty.chunks

       [Pretty.strs ("term code generators:" :: map fst codegens),

        Pretty.strs ("type code generators:" :: map fst tycodegens)]);

 end;

 structure CodegenData = TheoryDataFun(CodegenArgs);

 val print_codegens = CodegenData.print;

 (**** access parameters for random testing ****)

 fun get_test_params thy = #test_params (CodegenData.get thy);

 fun map_test_params f thy =

   let val {codegens, tycodegens, consts, types, attrs, test_params} =

     CodegenData.get thy;

   in CodegenData.put {codegens = codegens, tycodegens = tycodegens,

     consts = consts, types = types, attrs = attrs,

     test_params = f test_params} thy

   end;

 (**** add new code generators to theory ****)

 fun add_codegen name f thy =

   let val {codegens, tycodegens, consts, types, attrs, test_params} =

     CodegenData.get thy

   in (case assoc (codegens, name) of

       None => CodegenData.put {codegens = (name, f) :: codegens,

         tycodegens = tycodegens, consts = consts, types = types,

         attrs = attrs, test_params = test_params} thy

     | Some _ => error ("Code generator " ^ name ^ " already declared"))

   end;

 fun add_tycodegen name f thy =

   let val {codegens, tycodegens, consts, types, attrs, test_params} =

     CodegenData.get thy

   in (case assoc (tycodegens, name) of

       None => CodegenData.put {tycodegens = (name, f) :: tycodegens,

         codegens = codegens, consts = consts, types = types,

         attrs = attrs, test_params = test_params} thy

     | Some _ => error ("Code generator " ^ name ^ " already declared"))

   end;

 (**** code attribute ****)

 fun add_attribute name att thy =

   let val {codegens, tycodegens, consts, types, attrs, test_params} =

     CodegenData.get thy

   in (case assoc (attrs, name) of

       None => CodegenData.put {tycodegens = tycodegens,

         codegens = codegens, consts = consts, types = types,

         attrs = (name, att) :: attrs, test_params = test_params} thy

     | Some _ => error ("Code attribute " ^ name ^ " already declared"))

   end;

 fun mk_parser (a, p) = (if a = "" then Scan.succeed "" else Args.$$$ a) |-- p;

 val code_attr =

   Attrib.syntax (Scan.depend (fn thy => foldr op || (map mk_parser

     (#attrs (CodegenData.get thy)), Scan.fail) >> pair thy));

 (**** associate constants with target language code ****)

 fun gen_assoc_consts prep_type xs thy = foldl (fn (thy, (s, tyopt, syn)) =>

   let

     val sg = sign_of thy;

     val {codegens, tycodegens, consts, types, attrs, test_params} =

       CodegenData.get thy;

     val cname = Sign.intern_const sg s;

   in

     (case Sign.const_type sg cname of

        Some T =>

          let val T' = (case tyopt of

                 None => T

               | Some ty =>

                   let val U = prep_type sg ty

                   in if Sign.typ_instance sg (U, T) then U

                     else error ("Illegal type constraint for constant " ^ cname)

                   end)

          in (case assoc (consts, (cname, T')) of

              None => CodegenData.put {codegens = codegens,

                tycodegens = tycodegens,

                consts = ((cname, T'), syn) :: consts,

                types = types, attrs = attrs, test_params = test_params} thy

            | Some _ => error ("Constant " ^ cname ^ " already associated with code"))

          end

      | _ => error ("Not a constant: " ^ s))

   end) (thy, xs);

 val assoc_consts_i = gen_assoc_consts (K I);

 val assoc_consts = gen_assoc_consts (fn sg => typ_of o read_ctyp sg);

 (**** associate types with target language types ****)

 fun assoc_types xs thy = foldl (fn (thy, (s, syn)) =>

   let

     val {codegens, tycodegens, consts, types, attrs, test_params} =

       CodegenData.get thy;

     val tc = Sign.intern_tycon (sign_of thy) s

   in

     (case assoc (types, tc) of

        None => CodegenData.put {codegens = codegens,

          tycodegens = tycodegens, consts = consts,

          types = (tc, syn) :: types, attrs = attrs,

          test_params = test_params} thy

      | Some _ => error ("Type " ^ tc ^ " already associated with code"))

   end) (thy, xs);

 fun get_assoc_type thy s = assoc (#types (CodegenData.get thy), s);

 (**** make valid ML identifiers ****)

 fun gen_mk_id kind rename sg s =

   let

     val (xs as x::_) = explode (rename (space_implode "_"

       (NameSpace.unpack (Sign.cond_extern sg kind s))));

     fun check_str [] = ""

       | check_str (" " :: xs) = "_" ^ check_str xs

       | check_str (x :: xs) =

           (if Symbol.is_letdig x then x

            else "_" ^ string_of_int (ord x)) ^ check_str xs

   in

     (if not (Symbol.is_letter x) then "id" else "") ^ check_str xs

   end;

 val mk_const_id = gen_mk_id Sign.constK

   (fn s => if s mem ThmDatabase.ml_reserved then s ^ "_const" else s);

 val mk_type_id = gen_mk_id Sign.typeK

   (fn s => if s mem ThmDatabase.ml_reserved then s ^ "_type" else s);

 fun rename_terms ts =

   let

     val names = foldr add_term_names

       (ts, map (fst o fst) (Drule.vars_of_terms ts));

     val clash = names inter ThmDatabase.ml_reserved;

     val ps = clash ~~ variantlist (clash, names);

     fun rename (Var ((a, i), T)) = Var ((if_none (assoc (ps, a)) a, i), T)

       | rename (Free (a, T)) = Free (if_none (assoc (ps, a)) a, T)

       | rename (Abs (s, T, t)) = Abs (s, T, rename t)

       | rename (t $ u) = rename t $ rename u

       | rename t = t;

   in

     map rename ts

   end;

 val rename_term = hd o rename_terms o single;

 (**** retrieve definition of constant ****)

 fun is_instance thy T1 T2 =

   Sign.typ_instance (sign_of thy) (T1, Type.varifyT T2);

 fun get_assoc_code thy s T = apsome snd (find_first (fn ((s', T'), _) =>

   s = s' andalso is_instance thy T T') (#consts (CodegenData.get thy)));

 fun get_defn thy s T =

   let

     val axms = flat (map (Symtab.dest o #axioms o Theory.rep_theory)

       (thy :: Theory.ancestors_of thy));

     val defs = mapfilter (fn (_, t) =>

       (let

          val (lhs, rhs) = Logic.dest_equals t;

          val (c, args) = strip_comb lhs;

          val (s', T') = dest_Const c

        in if s=s' then Some (T', split_last (rename_terms (args @ [rhs])))

          else None end) handle TERM _ => None) axms;

     val i = find_index (is_instance thy T o fst) defs

   in

     if i>=0 then Some (snd (nth_elem (i, defs)),

       if length defs = 1 then None else Some i)

     else None

   end;

 (**** invoke suitable code generator for term / type ****)

 fun invoke_codegen thy dep brack (gr, t) = (case get_first

    (fn (_, f) => f thy gr dep brack t) (#codegens (CodegenData.get thy)) of

       None => error ("Unable to generate code for term:\n" ^

         Sign.string_of_term (sign_of thy) t ^ "\nrequired by:\n" ^

         commas (Graph.all_succs gr [dep]))

     | Some x => x);

 fun invoke_tycodegen thy dep brack (gr, T) = (case get_first

    (fn (_, f) => f thy gr dep brack T) (#tycodegens (CodegenData.get thy)) of

       None => error ("Unable to generate code for type:\n" ^

         Sign.string_of_typ (sign_of thy) T ^ "\nrequired by:\n" ^

         commas (Graph.all_succs gr [dep]))

     | Some x => x);

 (**** code generator for mixfix expressions ****)

 fun parens p = Pretty.block [Pretty.str "(", p, Pretty.str ")"];

 fun pretty_fn [] p = [p]

   | pretty_fn (x::xs) p = Pretty.str ("fn " ^ x ^ " =>") ::

       Pretty.brk 1 :: pretty_fn xs p;

 fun pretty_mixfix [] [] _ = []

   | pretty_mixfix (Arg :: ms) (p :: ps) qs = p :: pretty_mixfix ms ps qs

   | pretty_mixfix (Ignore :: ms) ps qs = pretty_mixfix ms ps qs

   | pretty_mixfix (Pretty p :: ms) ps qs = p :: pretty_mixfix ms ps qs

   | pretty_mixfix (Quote _ :: ms) ps (q :: qs) = q :: pretty_mixfix ms ps qs;

 (**** default code generators ****)

 fun eta_expand t ts i =

   let

     val (Ts, _) = strip_type (fastype_of t);

     val j = i - length ts

   in

     foldr (fn (T, t) => Abs ("x", T, t))

       (take (j, Ts), list_comb (t, ts @ map Bound (j-1 downto 0)))

   end;

 fun mk_app _ p [] = p

   | mk_app brack p ps = if brack then

        Pretty.block (Pretty.str "(" ::

          separate (Pretty.brk 1) (p :: ps) @ [Pretty.str ")"])

      else Pretty.block (separate (Pretty.brk 1) (p :: ps));

 fun new_names t xs = variantlist (xs,

   map (fst o fst o dest_Var) (term_vars t) union

   add_term_names (t, ThmDatabase.ml_reserved));

 fun new_name t x = hd (new_names t [x]);

 fun default_codegen thy gr dep brack t =

   let

     val (u, ts) = strip_comb t;

     fun codegens brack = foldl_map (invoke_codegen thy dep brack)

   in (case u of

       Var ((s, i), T) =>

         let

           val (gr', ps) = codegens true (gr, ts);

           val (gr'', _) = invoke_tycodegen thy dep false (gr', T)

         in Some (gr'', mk_app brack (Pretty.str (s ^

            (if i=0 then "" else string_of_int i))) ps)

         end

     | Free (s, T) =>

         let

           val (gr', ps) = codegens true (gr, ts);

           val (gr'', _) = invoke_tycodegen thy dep false (gr', T)

         in Some (gr'', mk_app brack (Pretty.str s) ps) end

     | Const (s, T) =>

       (case get_assoc_code thy s T of

          Some ms =>

            let val i = num_args ms

            in if length ts < i then

                default_codegen thy gr dep brack (eta_expand u ts i)

              else

                let

                  val (ts1, ts2) = args_of ms ts;

                  val (gr1, ps1) = codegens false (gr, ts1);

                  val (gr2, ps2) = codegens true (gr1, ts2);

                  val (gr3, ps3) = codegens false (gr2, quotes_of ms);

                in

                  Some (gr3, mk_app brack (Pretty.block (pretty_mixfix ms ps1 ps3)) ps2)

                end

            end

        | None => (case get_defn thy s T of

            None => None

          | Some ((args, rhs), k) =>

              let

                val id = mk_const_id (sign_of thy) s ^ (case k of

                  None => "" | Some i => "_def" ^ string_of_int i);

                val (gr', ps) = codegens true (gr, ts);

              in

                Some (Graph.add_edge (id, dep) gr' handle Graph.UNDEF _ =>

                  let

                    val _ = message ("expanding definition of " ^ s);

                    val (Ts, _) = strip_type T;

                    val (args', rhs') =

                      if not (null args) orelse null Ts then (args, rhs) else

                        let val v = Free (new_name rhs "x", hd Ts)

                        in ([v], betapply (rhs, v)) end;

                    val (gr1, p) = invoke_codegen thy id false

                      (Graph.add_edge (id, dep)

                         (Graph.new_node (id, (None, "")) gr'), rhs');

                    val (gr2, xs) = codegens false (gr1, args');

                    val (gr3, ty) = invoke_tycodegen thy id false (gr2, T);

                  in Graph.map_node id (K (None, Output.output (Pretty.string_of (Pretty.block

                    (separate (Pretty.brk 1) (if null args' then

                        [Pretty.str ("val " ^ id ^ " :"), ty]

                      else Pretty.str ("fun " ^ id) :: xs) @

                     [Pretty.str " =", Pretty.brk 1, p, Pretty.str ";"])) ^ "\n\n"))) gr3

                  end, mk_app brack (Pretty.str id) ps)

              end))

     | Abs _ =>

       let

         val (bs, Ts) = ListPair.unzip (strip_abs_vars u);

         val t = strip_abs_body u

         val bs' = new_names t bs;

         val (gr1, ps) = codegens true (gr, ts);

         val (gr2, p) = invoke_codegen thy dep false

           (gr1, subst_bounds (map Free (rev (bs' ~~ Ts)), t));

       in

         Some (gr2, mk_app brack (Pretty.block (Pretty.str "(" :: pretty_fn bs' p @

           [Pretty.str ")"])) ps)

       end

     | _ => None)

   end;

 fun default_tycodegen thy gr dep brack (TVar ((s, i), _)) =

       Some (gr, Pretty.str (s ^ (if i = 0 then "" else string_of_int i)))

   | default_tycodegen thy gr dep brack (TFree (s, _)) = Some (gr, Pretty.str s)

   | default_tycodegen thy gr dep brack (Type (s, Ts)) =

       (case assoc (#types (CodegenData.get thy), s) of

          None => None

        | Some ms =>

            let

              val (gr', ps) = foldl_map

                (invoke_tycodegen thy dep false) (gr, fst (args_of ms Ts));

              val (gr'', qs) = foldl_map

                (invoke_tycodegen thy dep false) (gr', quotes_of ms)

            in Some (gr'', Pretty.block (pretty_mixfix ms ps qs)) end);

 fun output_code gr xs = implode (map (snd o Graph.get_node gr)

   (rev (Graph.all_preds gr xs)));

 fun gen_generate_code prep_term thy =

   setmp print_mode [] (Pretty.setmp_margin (!margin) (fn xs =>

   let

     val sg = sign_of thy;

     val gr = Graph.new_node ("<Top>", (None, "")) Graph.empty;

     val (gr', ps) = foldl_map (fn (gr, (s, t)) => apsnd (pair s)

       (invoke_codegen thy "<Top>" false (gr, t)))

         (gr, map (apsnd (prep_term sg)) xs)

     val code =

       "structure Generated =\nstruct\n\n" ^

       output_code gr' ["<Top>"] ^

       space_implode "\n\n" (map (fn (s', p) => Pretty.string_of (Pretty.block

         [Pretty.str ("val " ^ s' ^ " ="), Pretty.brk 1, p, Pretty.str ";"])) ps) ^

       "\n\nend;\n\nopen Generated;\n";

   in Output.output code end));

 val generate_code_i = gen_generate_code (K I);

 val generate_code = gen_generate_code

   (fn sg => term_of o read_cterm sg o rpair TypeInfer.logicT);

 (**** Reflection ****)

 val strip_tname = implode o tl o explode;

 fun pretty_list xs = Pretty.block (Pretty.str "[" ::

   flat (separate [Pretty.str ",", Pretty.brk 1] (map single xs)) @

   [Pretty.str "]"]);

 fun mk_type p (TVar ((s, i), _)) = Pretty.str

       (strip_tname s ^ (if i = 0 then "" else string_of_int i) ^ "T")

   | mk_type p (TFree (s, _)) = Pretty.str (strip_tname s ^ "T")

   | mk_type p (Type (s, Ts)) = (if p then parens else I) (Pretty.block

       [Pretty.str "Type", Pretty.brk 1, Pretty.str ("(\"" ^ s ^ "\","),

        Pretty.brk 1, pretty_list (map (mk_type false) Ts), Pretty.str ")"]);

 fun mk_term_of sg p (TVar ((s, i), _)) = Pretty.str

       (strip_tname s ^ (if i = 0 then "" else string_of_int i) ^ "F")

   | mk_term_of sg p (TFree (s, _)) = Pretty.str (strip_tname s ^ "F")

   | mk_term_of sg p (Type (s, Ts)) = (if p then parens else I) (Pretty.block

       (separate (Pretty.brk 1) (Pretty.str ("term_of_" ^ mk_type_id sg s) ::

         flat (map (fn T => [mk_term_of sg true T, mk_type true T]) Ts))));

 (**** Test data generators ****)

 fun mk_gen sg p xs a (TVar ((s, i), _)) = Pretty.str

       (strip_tname s ^ (if i = 0 then "" else string_of_int i) ^ "G")

   | mk_gen sg p xs a (TFree (s, _)) = Pretty.str (strip_tname s ^ "G")

   | mk_gen sg p xs a (Type (s, Ts)) = (if p then parens else I) (Pretty.block

       (separate (Pretty.brk 1) (Pretty.str ("gen_" ^ mk_type_id sg s ^

         (if s mem xs then "'" else "")) :: map (mk_gen sg true xs a) Ts @

         (if s mem xs then [Pretty.str a] else []))));

 val test_fn : (int -> (string * term) list option) ref = ref (fn _ => None);

 fun test_term thy sz i t =

   let

     val _ = assert (null (term_tvars t) andalso null (term_tfrees t))

       "Term to be tested contains type variables";

     val _ = assert (null (term_vars t))

       "Term to be tested contains schematic variables";

     val sg = sign_of thy;

     val frees = map dest_Free (term_frees t);

     val szname = variant (map fst frees) "i";

     val s = "structure TestTerm =\nstruct\n\n" ^

       setmp mode ["term_of", "test"] (generate_code_i thy)

         [("testf", list_abs_free (frees, t))] ^

       "\n" ^ Output.output (Pretty.string_of

         (Pretty.block [Pretty.str "val () = Codegen.test_fn :=",

           Pretty.brk 1, Pretty.str ("(fn " ^ szname ^ " =>"), Pretty.brk 1,

           Pretty.blk (0, [Pretty.str "let", Pretty.brk 1,

             Pretty.blk (0, separate Pretty.fbrk (map (fn (s, T) =>

               Pretty.block [Pretty.str ("val " ^ s ^ " ="), Pretty.brk 1,

               mk_gen sg false [] "" T, Pretty.brk 1,

               Pretty.str (szname ^ ";")]) frees)),

             Pretty.brk 1, Pretty.str "in", Pretty.brk 1,

             Pretty.block [Pretty.str "if ",

               mk_app false (Pretty.str "testf") (map (Pretty.str o fst) frees),

               Pretty.brk 1, Pretty.str "then Library.None",

               Pretty.brk 1, Pretty.str "else ",

               Pretty.block [Pretty.str "Library.Some ", Pretty.block (Pretty.str "[" ::

                 flat (separate [Pretty.str ",", Pretty.brk 1]

                   (map (fn (s, T) => [Pretty.block

                     [Pretty.str ("(" ^ Library.quote s ^ ","), Pretty.brk 1,

                      mk_app false (mk_term_of sg false T)

                        [Pretty.str s], Pretty.str ")"]]) frees)) @

                   [Pretty.str "]"])]],

             Pretty.brk 1, Pretty.str "end"]), Pretty.str ");"])) ^

       "\n\nend;\n";

     val _ = use_text Context.ml_output false s;

     fun iter f k = if k > i then None

       else (case (f () handle Match =>

           (warning "Exception Match raised in generated code"; None)) of

         None => iter f (k+1) | Some x => Some x);

     fun test k = if k > sz then None

       else (priority ("Test data size: " ^ string_of_int k);

         case iter (fn () => !test_fn k) 1 of

           None => test (k+1) | Some x => Some x);

   in test 0 end;

 fun test_goal ({size, iterations, default_type}, tvinsts) i st =

   let

     val sg = Toplevel.sign_of st;

     fun strip (Const ("all", _) $ Abs (_, _, t)) = strip t

       | strip t = t;

     val (gi, frees) = Logic.goal_params

       (prop_of (snd (snd (Proof.get_goal (Toplevel.proof_of st))))) i;

     val gi' = ObjectLogic.atomize_term sg (map_term_types

       (map_type_tfree (fn p as (s, _) => if_none (assoc (tvinsts, s))

         (if_none default_type (TFree p)))) (subst_bounds (frees, strip gi)));

   in case test_term (Toplevel.theory_of st) size iterations gi' of

       None => writeln "No counterexamples found."

     | Some cex => writeln ("Counterexample found:\n" ^

         Pretty.string_of (Pretty.chunks (map (fn (s, t) =>

           Pretty.block [Pretty.str (s ^ " ="), Pretty.brk 1,

             Sign.pretty_term sg t]) cex)))

   end;

 (**** Interface ****)

 val str = setmp print_mode [] Pretty.str;

 fun parse_mixfix rd s =

   (case Scan.finite Symbol.stopper (Scan.repeat

      (   $$ "_" >> K Arg

       || $$ "?" >> K Ignore

       || $$ "/" |-- Scan.repeat ($$ " ") >> (Pretty o Pretty.brk o length)

       || $$ "{" |-- $$ "*" |-- Scan.repeat1

            (   $$ "'" |-- Scan.one Symbol.not_eof

             || Scan.unless ($$ "*" -- $$ "}") (Scan.one Symbol.not_eof)) --|

          $$ "*" --| $$ "}" >> (Quote o rd o implode)

       || Scan.repeat1

            (   $$ "'" |-- Scan.one Symbol.not_eof

             || Scan.unless ($$ "_" || $$ "?" || $$ "/" || $$ "{" |-- $$ "*")

                  (Scan.one Symbol.not_eof)) >> (Pretty o str o implode)))

        (Symbol.explode s) of

      (p, []) => p

    | _ => error ("Malformed annotation: " ^ quote s));

 structure P = OuterParse and K = OuterSyntax.Keyword;

 val assoc_typeP =

   OuterSyntax.command "types_code"

   "associate types with target language types" K.thy_decl

     (Scan.repeat1 (P.xname --| P.$$$ "(" -- P.string --| P.$$$ ")") >>

      (fn xs => Toplevel.theory (fn thy => assoc_types

        (map (fn (name, mfx) => (name, parse_mixfix

          (typ_of o read_ctyp (sign_of thy)) mfx)) xs) thy)));

 val assoc_constP =

   OuterSyntax.command "consts_code"

   "associate constants with target language code" K.thy_decl

     (Scan.repeat1

        (P.xname -- (Scan.option (P.$$$ "::" |-- P.typ)) --|

         P.$$$ "(" -- P.string --| P.$$$ ")") >>

      (fn xs => Toplevel.theory (fn thy => assoc_consts

        (map (fn ((name, optype), mfx) => (name, optype, parse_mixfix

          (term_of o read_cterm (sign_of thy) o rpair TypeInfer.logicT) mfx))

            xs) thy)));

 val generate_codeP =

   OuterSyntax.command "generate_code" "generates code for terms" K.thy_decl

     (Scan.option (P.$$$ "(" |-- P.name --| P.$$$ ")") --

      Scan.optional (P.$$$ "[" |-- P.enum "," P.xname --| P.$$$ "]") (!mode) --

      Scan.repeat1 (P.name --| P.$$$ "=" -- P.term) >>

      (fn ((opt_fname, mode'), xs) => Toplevel.theory (fn thy =>

         ((case opt_fname of

             None => use_text Context.ml_output false

           | Some fname => File.write (Path.unpack fname))

               (setmp mode mode' (generate_code thy) xs); thy))));

 val params =

   [("size", P.nat >> (K o set_size)),

    ("iterations", P.nat >> (K o set_iterations)),

    ("default_type", P.typ >> set_default_type)];

 val parse_test_params = P.short_ident :-- (fn s =>

   P.$$$ "=" |-- if_none (assoc (params, s)) Scan.fail) >> snd;

 fun parse_tyinst xs =

   (P.type_ident --| P.$$$ "=" -- P.typ >> (fn (v, s) => fn sg =>

     fn (x, ys) => (x, (v, typ_of (read_ctyp sg s)) :: ys))) xs;

 fun app [] x = x

   | app (f :: fs) x = app fs (f x);

 val test_paramsP =

   OuterSyntax.command "quickcheck_params" "set parameters for random testing" K.thy_decl

     (P.$$$ "[" |-- P.list1 parse_test_params --| P.$$$ "]" >>

       (fn fs => Toplevel.theory (fn thy =>

          map_test_params (app (map (fn f => f (sign_of thy)) fs)) thy)));

 val testP =

   OuterSyntax.command "quickcheck" "try to find counterexample for subgoal" K.diag

   (Scan.option (P.$$$ "[" |-- P.list1

     (   parse_test_params >> (fn f => fn sg => apfst (f sg))

      || parse_tyinst) --| P.$$$ "]") -- Scan.optional P.nat 1 >>

     (fn (ps, g) => Toplevel.keep (fn st =>

       test_goal (app (if_none (apsome

           (map (fn f => f (Toplevel.sign_of st))) ps) [])

         (get_test_params (Toplevel.theory_of st), [])) g st)));

 val parsers = [assoc_typeP, assoc_constP, generate_codeP, test_paramsP, testP];

 val setup =

   [CodegenData.init,

    add_codegen "default" default_codegen,

    add_tycodegen "default" default_tycodegen,

    assoc_types [("fun", parse_mixfix (K dummyT) "(_ ->/ _)")],

    Attrib.add_attributes [("code",

      (code_attr, K Attrib.undef_local_attribute),

      "declare theorems for code generation")]];

 end;

 OuterSyntax.add_parsers Codegen.parsers;