(*  Title:      Pure/codegen.ML

     Author:     Stefan Berghofer, TU Muenchen

 Generic code generator.

 *)

 signature CODEGEN =

 sig

   val quiet_mode : bool Unsynchronized.ref

   val message : string -> unit

   val mode : string list Unsynchronized.ref

   val margin : int Unsynchronized.ref

   val string_of : Pretty.T -> string

   val str : string -> Pretty.T

   datatype 'a mixfix =

       Arg

     | Ignore

     | Module

     | Pretty of Pretty.T

     | Quote of 'a;

   type deftab

   type node

   type codegr

   type 'a codegen

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

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

   val add_preprocessor: (theory -> thm list -> thm list) -> theory -> theory

   val preprocess: theory -> thm list -> thm list

   val preprocess_term: theory -> term -> term

   val print_codegens: theory -> unit

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

     (string * string) list * codegr

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

     (string * string) list * codegr

   val assoc_const: string * (term mixfix list *

     (string * string) list) -> theory -> theory

   val assoc_const_i: (string * typ) * (term mixfix list *

     (string * string) list) -> theory -> theory

   val assoc_type: xstring * (typ mixfix list *

     (string * string) list) -> theory -> theory

   val get_assoc_code: theory -> string * typ ->

     (term mixfix list * (string * string) list) option

   val get_assoc_type: theory -> string ->

     (typ mixfix list * (string * string) list) option

   val codegen_error: codegr -> string -> string -> 'a

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

     term -> codegr -> Pretty.T * codegr

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

     typ -> codegr -> Pretty.T * codegr

   val mk_id: string -> string

   val mk_qual_id: string -> string * string -> string

   val mk_const_id: string -> string -> codegr -> (string * string) * codegr

   val get_const_id: codegr -> string -> string * string

   val mk_type_id: string -> string -> codegr -> (string * string) * codegr

   val get_type_id: codegr -> string -> string * string

   val thyname_of_type: theory -> string -> string

   val thyname_of_const: theory -> string -> string

   val rename_terms: term list -> term list

   val rename_term: term -> term

   val new_names: term -> string list -> string list

   val new_name: term -> string -> string

   val if_library: 'a -> 'a -> 'a

   val get_defn: theory -> deftab -> string -> typ ->

     ((typ * (string * thm)) * int option) option

   val is_instance: typ -> typ -> bool

   val parens: Pretty.T -> Pretty.T

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

   val mk_tuple: Pretty.T list -> Pretty.T

   val mk_let: (Pretty.T * Pretty.T) list -> Pretty.T -> 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: codegr -> string -> bool -> typ -> Pretty.T

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

   val test_fn: (int -> term list option) Unsynchronized.ref

   val test_term: Proof.context -> bool -> term -> int -> term list option * (bool list * bool)

   val eval_result: (unit -> term) Unsynchronized.ref

   val eval_term: theory -> term -> term

   val evaluation_conv: cterm -> thm

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

   val quotes_of: 'a mixfix list -> 'a list

   val num_args_of: 'a mixfix list -> int

   val replace_quotes: 'b list -> 'a mixfix list -> 'b mixfix list

   val mk_deftab: theory -> deftab

   val map_unfold: (simpset -> simpset) -> theory -> theory

   val add_unfold: thm -> theory -> theory

   val del_unfold: thm -> theory -> theory

   val get_node: codegr -> string -> node

   val add_edge: string * string -> codegr -> codegr

   val add_edge_acyclic: string * string -> codegr -> codegr

   val del_nodes: string list -> codegr -> codegr

   val map_node: string -> (node -> node) -> codegr -> codegr

   val new_node: string * node -> codegr -> codegr

   val setup: theory -> theory

 end;

 structure Codegen : CODEGEN =

 struct

 val quiet_mode = Unsynchronized.ref true;

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

 val mode = Unsynchronized.ref ([] : string list);   (* FIXME proper functional argument *)

 val margin = Unsynchronized.ref 80;

 fun string_of p = Print_Mode.setmp [] (Pretty.string_of_margin (!margin)) p;

 val str = Print_Mode.setmp [] Pretty.str;

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

 datatype 'a mixfix =

     Arg

   | Ignore

   | Module

   | 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_of x = length (filter is_arg x);

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

 (* preprocessed definition table *)

 type deftab =

   (typ *              (* type of constant *)

     (string *         (* name of theory containing definition of constant *)

       thm))           (* definition theorem *)

   list Symtab.table;

 (* code dependency graph *)

 type nametab = (string * string) Symtab.table * unit Symtab.table;

 fun merge_nametabs ((tab, used) : nametab, (tab', used')) =

   (Symtab.merge op = (tab, tab'), Symtab.merge op = (used, used'));

 type node =

   (exn option *    (* slot for arbitrary data *)

    string *        (* name of structure containing piece of code *)

    string);        (* piece of code *)

 type codegr =

   node Graph.T *

   (nametab *       (* table for assigned constant names *)

    nametab);       (* table for assigned type names *)

 val emptygr : codegr = (Graph.empty,

   ((Symtab.empty, Symtab.empty), (Symtab.empty, Symtab.empty)));

 (* type of code generators *)

 type 'a codegen =

   theory ->    (* theory in which generate_code was called *)

   deftab ->    (* definition table (for efficiency) *)

   string ->    (* node name of caller (for recording dependencies) *)

   string ->    (* module name of caller (for modular code generation) *)

   bool ->      (* whether to parenthesize generated expression *)

   'a ->        (* item to generate code from *)

   codegr ->    (* code dependency graph *)

   (Pretty.T * codegr) option;

 (* theory data *)

 structure CodegenData = Theory_Data

 (

   type T =

     {codegens : (string * term codegen) list,

      tycodegens : (string * typ codegen) list,

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

      types : (string * (typ mixfix list * (string * string) list)) list,

      preprocs: (stamp * (theory -> thm list -> thm list)) list,

      modules: codegr Symtab.table};

   val empty =

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

      preprocs = [], modules = Symtab.empty};

   val extend = I;

   fun merge

     ({codegens = codegens1, tycodegens = tycodegens1,

       consts = consts1, types = types1,

       preprocs = preprocs1, modules = modules1} : T,

      {codegens = codegens2, tycodegens = tycodegens2,

       consts = consts2, types = types2,

       preprocs = preprocs2, modules = modules2}) : T =

     {codegens = AList.merge (op =) (K true) (codegens1, codegens2),

      tycodegens = AList.merge (op =) (K true) (tycodegens1, tycodegens2),

      consts = AList.merge (op =) (K true) (consts1, consts2),

      types = AList.merge (op =) (K true) (types1, types2),

      preprocs = AList.merge (op =) (K true) (preprocs1, preprocs2),

      modules = Symtab.merge (K true) (modules1, modules2)};

 );

 fun print_codegens thy =

   let val {codegens, tycodegens, ...} = CodegenData.get thy in

     Pretty.writeln (Pretty.chunks

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

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

   end;

 (**** access modules ****)

 fun get_modules thy = #modules (CodegenData.get thy);

 fun map_modules f thy =

   let val {codegens, tycodegens, consts, types, preprocs, modules} =

     CodegenData.get thy;

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

     consts = consts, types = types, preprocs = preprocs,

     modules = f modules} thy

   end;

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

 fun add_codegen name f thy =

   let val {codegens, tycodegens, consts, types, preprocs, modules} =

     CodegenData.get thy

   in (case AList.lookup (op =) codegens name of

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

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

         preprocs = preprocs, modules = modules} thy

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

   end;

 fun add_tycodegen name f thy =

   let val {codegens, tycodegens, consts, types, preprocs, modules} =

     CodegenData.get thy

   in (case AList.lookup (op =) tycodegens name of

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

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

         preprocs = preprocs, modules = modules} thy

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

   end;

 (**** preprocessors ****)

 fun add_preprocessor p thy =

   let val {codegens, tycodegens, consts, types, preprocs, modules} =

     CodegenData.get thy

   in CodegenData.put {tycodegens = tycodegens,

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

     preprocs = (stamp (), p) :: preprocs,

     modules = modules} thy

   end;

 fun preprocess thy =

   let val {preprocs, ...} = CodegenData.get thy

   in fold (fn (_, f) => f thy) preprocs end;

 fun preprocess_term thy t =

   let

     val x = Free (Name.variant (OldTerm.add_term_names (t, [])) "x", fastype_of t);

     (* fake definition *)

     val eq = Skip_Proof.make_thm thy (Logic.mk_equals (x, t));

     fun err () = error "preprocess_term: bad preprocessor"

   in case map prop_of (preprocess thy [eq]) of

       [Const ("==", _) $ x' $ t'] => if x = x' then t' else err ()

     | _ => err ()

   end;

 structure UnfoldData = Theory_Data

 (

   type T = simpset;

   val empty = empty_ss;

   val extend = I;

   val merge = merge_ss;

 );

 val map_unfold = UnfoldData.map;

 val add_unfold = map_unfold o MetaSimplifier.add_simp;

 val del_unfold = map_unfold o MetaSimplifier.del_simp;

 fun unfold_preprocessor thy =

   let val ss = Simplifier.global_context thy (UnfoldData.get thy)

   in map (Thm.transfer thy #> Simplifier.full_simplify ss) end;

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

 fun gen_assoc_const prep_const (raw_const, syn) thy =

   let

     val {codegens, tycodegens, consts, types, preprocs, modules} =

       CodegenData.get thy;

     val (cname, T) = prep_const thy raw_const;

   in

     if num_args_of (fst syn) > length (binder_types T) then

       error ("More arguments than in corresponding type of " ^ cname)

     else case AList.lookup (op =) consts (cname, T) of

       NONE => CodegenData.put {codegens = codegens,

         tycodegens = tycodegens,

         consts = ((cname, T), syn) :: consts,

         types = types, preprocs = preprocs,

         modules = modules} thy

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

   end;

 val assoc_const_i = gen_assoc_const (K I);

 val assoc_const = gen_assoc_const Code.read_bare_const;

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

 fun assoc_type (s, syn) thy =

   let

     val {codegens, tycodegens, consts, types, preprocs, modules} =

       CodegenData.get thy;

     val tc = Sign.intern_type thy s;

   in

     case Symtab.lookup (snd (#types (Type.rep_tsig (Sign.tsig_of thy)))) tc of

       SOME (Type.LogicalType i) =>

         if num_args_of (fst syn) > i then

           error ("More arguments than corresponding type constructor " ^ s)

         else

           (case AList.lookup (op =) types tc of

             NONE => CodegenData.put {codegens = codegens,

               tycodegens = tycodegens, consts = consts,

               types = (tc, syn) :: types,

               preprocs = preprocs, modules = modules} thy

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

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

   end;

 fun get_assoc_type thy = AList.lookup (op =) ((#types o CodegenData.get) thy);

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

 fun is_ascii_letdig x = Symbol.is_ascii_letter x orelse

   Symbol.is_ascii_digit x orelse Symbol.is_ascii_quasi x;

 fun dest_sym s = (case split_last (snd (take_prefix (fn c => c = "\\") (explode s))) of

     ("<" :: "^" :: xs, ">") => (true, implode xs)

   | ("<" :: xs, ">") => (false, implode xs)

   | _ => sys_error "dest_sym");

 fun mk_id s = if s = "" then "" else

   let

     fun check_str [] = []

       | check_str xs = (case take_prefix is_ascii_letdig xs of

           ([], " " :: zs) => check_str zs

         | ([], z :: zs) =>

           if size z = 1 then string_of_int (ord z) :: check_str zs

           else (case dest_sym z of

               (true, "isub") => check_str zs

             | (true, "isup") => "" :: check_str zs

             | (ctrl, s') => (if ctrl then "ctrl_" ^ s' else s') :: check_str zs)

         | (ys, zs) => implode ys :: check_str zs);

     val s' = space_implode "_" (maps (check_str o Symbol.explode) (Long_Name.explode s))

   in

     if Symbol.is_ascii_letter (hd (explode s')) then s' else "id_" ^ s'

   end;

 fun mk_long_id (p as (tab, used)) module s =

   let

     fun find_name [] = sys_error "mk_long_id"

       | find_name (ys :: yss) =

           let

             val s' = Long_Name.implode ys

             val s'' = Long_Name.append module s'

           in case Symtab.lookup used s'' of

               NONE => ((module, s'),

                 (Symtab.update_new (s, (module, s')) tab,

                  Symtab.update_new (s'', ()) used))

             | SOME _ => find_name yss

           end

   in case Symtab.lookup tab s of

       NONE => find_name (Library.suffixes1 (Long_Name.explode s))

     | SOME name => (name, p)

   end;

 (* module:  module name for caller                                        *)

 (* module': module name for callee                                        *)

 (* if caller and callee reside in different modules, use qualified access *)

 fun mk_qual_id module (module', s) =

   if module = module' orelse module' = "" then s else module' ^ "." ^ s;

 fun mk_const_id module cname (gr, (tab1, tab2)) =

   let

     val ((module, s), tab1') = mk_long_id tab1 module cname

     val s' = mk_id s;

     val s'' = if ML_Syntax.is_reserved s' then s' ^ "_const" else s'

   in (((module, s'')), (gr, (tab1', tab2))) end;

 fun get_const_id (gr, (tab1, tab2)) cname =

   case Symtab.lookup (fst tab1) cname of

     NONE => error ("get_const_id: no such constant: " ^ quote cname)

   | SOME (module, s) =>

       let

         val s' = mk_id s;

         val s'' = if ML_Syntax.is_reserved s' then s' ^ "_const" else s'

       in (module, s'') end;

 fun mk_type_id module tyname (gr, (tab1, tab2)) =

   let

     val ((module, s), tab2') = mk_long_id tab2 module tyname

     val s' = mk_id s;

     val s'' = if ML_Syntax.is_reserved s' then s' ^ "_type" else s'

   in ((module, s''), (gr, (tab1, tab2'))) end;

 fun get_type_id (gr, (tab1, tab2)) tyname =

   case Symtab.lookup (fst tab2) tyname of

     NONE => error ("get_type_id: no such type: " ^ quote tyname)

   | SOME (module, s) =>

       let

         val s' = mk_id s;

         val s'' = if ML_Syntax.is_reserved s' then s' ^ "_type" else s'

       in (module, s'') end;

 fun get_type_id' f tab tyname = apsnd f (get_type_id tab tyname);

 fun get_node (gr, x) k = Graph.get_node gr k;

 fun add_edge e (gr, x) = (Graph.add_edge e gr, x);

 fun add_edge_acyclic e (gr, x) = (Graph.add_edge_acyclic e gr, x);

 fun del_nodes ks (gr, x) = (Graph.del_nodes ks gr, x);

 fun map_node k f (gr, x) = (Graph.map_node k f gr, x);

 fun new_node p (gr, x) = (Graph.new_node p gr, x);

 fun thyname_of_type thy = #theory_name o Name_Space.the_entry (Sign.type_space thy);

 fun thyname_of_const thy = #theory_name o Name_Space.the_entry (Sign.const_space thy);

 fun rename_terms ts =

   let

     val names = List.foldr OldTerm.add_term_names

       (map (fst o fst) (rev (fold Term.add_vars ts []))) ts;

     val reserved = filter ML_Syntax.is_reserved names;

     val (illegal, alt_names) = split_list (map_filter (fn s =>

       let val s' = mk_id s in if s = s' then NONE else SOME (s, s') end) names)

     val ps = (reserved @ illegal) ~~

       Name.variant_list names (map (suffix "'") reserved @ alt_names);

     fun rename_id s = AList.lookup (op =) ps s |> the_default s;

     fun rename (Var ((a, i), T)) = Var ((rename_id a, i), T)

       | rename (Free (a, T)) = Free (rename_id 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 T1 T2 =

   Type.raw_instance (T1, if null (OldTerm.typ_tfrees T2) then T2 else Logic.varifyT_global T2);

 fun get_assoc_code thy (s, T) = Option.map snd (find_first (fn ((s', T'), _) =>

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

 fun get_aux_code xs = map_filter (fn (m, code) =>

   if m = "" orelse member (op =) (!mode) m then SOME code else NONE) xs;

 fun dest_prim_def t =

   let

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

     val (c, args) = strip_comb lhs;

     val (s, T) = dest_Const c

   in if forall is_Var args then SOME (s, (T, (args, rhs))) else NONE

   end handle TERM _ => NONE;

 fun mk_deftab thy =

   let

     val axmss = map (fn thy' => (Context.theory_name thy', Theory.axiom_table thy'))

       (thy :: Theory.ancestors_of thy);

     fun add_def thyname (name, t) = (case dest_prim_def t of

         NONE => I

       | SOME (s, (T, _)) => Symtab.map_default (s, [])

           (cons (T, (thyname, Thm.axiom thy name))));

   in

     fold (fn (thyname, axms) => Symtab.fold (add_def thyname) axms) axmss Symtab.empty

   end;

 fun prep_prim_def thy thm =

   let

     val prop = case preprocess thy [thm]

      of [thm'] => Thm.prop_of thm'

       | _ => error "mk_deftab: bad preprocessor"

   in ((Option.map o apsnd o apsnd)

     (fn (args, rhs) => split_last (rename_terms (args @ [rhs]))) o dest_prim_def) prop

   end;

 fun get_defn thy defs s T = (case Symtab.lookup defs s of

     NONE => NONE

   | SOME ds =>

       let val i = find_index (is_instance T o fst) ds

       in if i >= 0 then

           SOME (nth ds i, if length ds = 1 then NONE else SOME i)

         else NONE

       end);

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

 fun codegen_error (gr, _) dep s =

   error (s ^ "\nrequired by:\n" ^ commas (Graph.all_succs gr [dep]));

 fun invoke_codegen thy defs dep module brack t gr = (case get_first

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

       NONE => codegen_error gr dep ("Unable to generate code for term:\n" ^

         Syntax.string_of_term_global thy t)

     | SOME x => x);

 fun invoke_tycodegen thy defs dep module brack T gr = (case get_first

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

       NONE => codegen_error gr dep ("Unable to generate code for type:\n" ^

         Syntax.string_of_typ_global thy T)

     | SOME x => x);

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

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

 fun pretty_fn [] p = [p]

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

       Pretty.brk 1 :: pretty_fn xs p;

 fun pretty_mixfix _ _ [] [] _ = []

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

       p :: pretty_mixfix module module' ms ps qs

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

       pretty_mixfix module module' ms ps qs

   | pretty_mixfix module module' (Module :: ms) ps qs =

       (if module <> module'

        then cons (str (module' ^ ".")) else I)

       (pretty_mixfix module module' ms ps qs)

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

       p :: pretty_mixfix module module' ms ps qs

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

       q :: pretty_mixfix module module' ms ps qs;

 fun replace_quotes [] [] = []

   | replace_quotes xs (Arg :: ms) =

       Arg :: replace_quotes xs ms

   | replace_quotes xs (Ignore :: ms) =

       Ignore :: replace_quotes xs ms

   | replace_quotes xs (Module :: ms) =

       Module :: replace_quotes xs ms

   | replace_quotes xs (Pretty p :: ms) =

       Pretty p :: replace_quotes xs ms

   | replace_quotes (x::xs) (Quote _ :: ms) =

       Quote x :: replace_quotes xs ms;

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

 fun eta_expand t ts i =

   let

     val k = length ts;

     val Ts = drop k (binder_types (fastype_of t));

     val j = i - k

   in

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

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

   end;

 fun mk_app _ p [] = p

   | mk_app brack p ps = if brack then

        Pretty.block (str "(" ::

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

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

 fun new_names t xs = Name.variant_list

   (union (op =) (map (fst o fst o dest_Var) (OldTerm.term_vars t))

     (OldTerm.add_term_names (t, ML_Syntax.reserved_names))) (map mk_id xs);

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

 fun if_library x y = if member (op =) (!mode) "library" then x else y;

 fun default_codegen thy defs dep module brack t gr =

   let

     val (u, ts) = strip_comb t;

     fun codegens brack = fold_map (invoke_codegen thy defs dep module brack)

   in (case u of

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

         let

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

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

         in SOME (mk_app brack (str (s ^

            (if i=0 then "" else string_of_int i))) ps, gr'')

         end

     | Free (s, T) =>

         let

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

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

         in SOME (mk_app brack (str s) ps, gr'') end

     | Const (s, T) =>

       (case get_assoc_code thy (s, T) of

          SOME (ms, aux) =>

            let val i = num_args_of ms

            in if length ts < i then

                default_codegen thy defs dep module brack (eta_expand u ts i) gr 

              else

                let

                  val (ts1, ts2) = args_of ms ts;

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

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

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

                  val (_, gr4) = invoke_tycodegen thy defs dep module false

                    (funpow (length ts) (hd o tl o snd o dest_Type) T) gr3;

                  val (module', suffix) = (case get_defn thy defs s T of

                      NONE => (if_library (thyname_of_const thy s) module, "")

                    | SOME ((U, (module', _)), NONE) =>

                        (if_library module' module, "")

                    | SOME ((U, (module', _)), SOME i) =>

                        (if_library module' module, " def" ^ string_of_int i));

                  val node_id = s ^ suffix;

                  fun p module' = mk_app brack (Pretty.block

                    (pretty_mixfix module module' ms ps1 ps3)) ps2

                in SOME (case try (get_node gr4) node_id of

                    NONE => (case get_aux_code aux of

                        [] => (p module, gr4)

                      | xs => (p module', add_edge (node_id, dep) (new_node

                          (node_id, (NONE, module', cat_lines xs ^ "\n")) gr4)))

                  | SOME (_, module'', _) =>

                      (p module'', add_edge (node_id, dep) gr4))

                end

            end

        | NONE => (case get_defn thy defs s T of

            NONE => NONE

          | SOME ((U, (thyname, thm)), k) => (case prep_prim_def thy thm

             of SOME (_, (_, (args, rhs))) => let

                val module' = if_library thyname module;

                val suffix = (case k of NONE => "" | SOME i => " def" ^ string_of_int i);

                val node_id = s ^ suffix;

                val ((ps, def_id), gr') = gr |> codegens true ts

                  ||>> mk_const_id module' (s ^ suffix);

                val p = mk_app brack (str (mk_qual_id module def_id)) ps

              in SOME (case try (get_node gr') node_id of

                  NONE =>

                    let

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

                      val (Ts, _) = strip_type U;

                      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 (p', gr1) = invoke_codegen thy defs node_id module' false

                        rhs' (add_edge (node_id, dep)

                           (new_node (node_id, (NONE, "", "")) gr'));

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

                      val (_, gr3) = invoke_tycodegen thy defs dep module false T gr2;

                      val (ty, gr4) = invoke_tycodegen thy defs node_id module' false U gr3;

                    in (p, map_node node_id (K (NONE, module', string_of

                        (Pretty.block (separate (Pretty.brk 1)

                          (if null args' then

                             [str ("val " ^ snd def_id ^ " :"), ty]

                           else str ("fun " ^ snd def_id) :: xs) @

                         [str " =", Pretty.brk 1, p', str ";"])) ^ "\n\n")) gr4)

                    end

                | SOME _ => (p, add_edge (node_id, dep) gr'))

              end

              | NONE => NONE)))

     | Abs _ =>

       let

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

         val t = strip_abs_body u

         val bs' = new_names t bs;

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

         val (p, gr2) = invoke_codegen thy defs dep module false

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

       in

         SOME (mk_app brack (Pretty.block (str "(" :: pretty_fn bs' p @

           [str ")"])) ps, gr2)

       end

     | _ => NONE)

   end;

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

       SOME (str (s ^ (if i = 0 then "" else string_of_int i)), gr)

   | default_tycodegen thy defs dep module brack (TFree (s, _)) gr =

       SOME (str s, gr)

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

       (case AList.lookup (op =) ((#types o CodegenData.get) thy) s of

          NONE => NONE

        | SOME (ms, aux) =>

            let

              val (ps, gr') = fold_map

                (invoke_tycodegen thy defs dep module false)

                (fst (args_of ms Ts)) gr;

              val (qs, gr'') = fold_map

                (invoke_tycodegen thy defs dep module false)

                (quotes_of ms) gr';

              val module' = if_library (thyname_of_type thy s) module;

              val node_id = s ^ " (type)";

              fun p module' = Pretty.block (pretty_mixfix module module' ms ps qs)

            in SOME (case try (get_node gr'') node_id of

                NONE => (case get_aux_code aux of

                    [] => (p module', gr'')

                  | xs => (p module', snd (mk_type_id module' s

                        (add_edge (node_id, dep) (new_node (node_id,

                          (NONE, module', cat_lines xs ^ "\n")) gr'')))))

              | SOME (_, module'', _) =>

                  (p module'', add_edge (node_id, dep) gr''))

            end);

 fun mk_tuple [p] = p

   | mk_tuple ps = Pretty.block (str "(" ::

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

 fun mk_let bindings body =

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

     Pretty.blk (0, separate Pretty.fbrk (map (fn (pat, rhs) =>

       Pretty.block [str "val ", pat, str " =", Pretty.brk 1,

       rhs, str ";"]) bindings)),

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

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

 fun mk_struct name s = "structure " ^ name ^ " =\nstruct\n\n" ^ s ^ "end;\n";

 fun add_to_module name s = AList.map_entry (op =) (name : string) (suffix s);

 fun output_code gr module xs =

   let

     val code = map_filter (fn s =>

       let val c as (_, module', _) = Graph.get_node gr s

       in if module = "" orelse module = module' then SOME (s, c) else NONE end)

         (rev (Graph.all_preds gr xs));

     fun string_of_cycle (a :: b :: cs) =

           let val SOME (x, y) = get_first (fn (x, (_, a', _)) =>

             if a = a' then Option.map (pair x)

               (find_first ((fn (_, b', _) => b' = b) o Graph.get_node gr)

                 (Graph.imm_succs gr x))

             else NONE) code

           in x ^ " called by " ^ y ^ "\n" ^ string_of_cycle (b :: cs) end

       | string_of_cycle _ = ""

   in

     if module = "" then

       let

         val modules = distinct (op =) (map (#2 o snd) code);

         val mod_gr = fold_rev Graph.add_edge_acyclic

           (maps (fn (s, (_, module, _)) => map (pair module)

             (filter_out (fn s => s = module) (map (#2 o Graph.get_node gr)

               (Graph.imm_succs gr s)))) code)

           (fold_rev (Graph.new_node o rpair ()) modules Graph.empty);

         val modules' =

           rev (Graph.all_preds mod_gr (map (#2 o Graph.get_node gr) xs))

       in

         List.foldl (fn ((_, (_, module, s)), ms) => add_to_module module s ms)

           (map (rpair "") modules') code

       end handle Graph.CYCLES (cs :: _) =>

         error ("Cyclic dependency of modules:\n" ^ commas cs ^

           "\n" ^ string_of_cycle cs)

     else [(module, implode (map (#3 o snd) code))]

   end;

 fun gen_generate_code prep_term thy modules module xs =

   let

     val _ = (module <> "" orelse

         member (op =) (!mode) "library" andalso forall (fn (s, _) => s = "") xs)

       orelse error "missing module name";

     val graphs = get_modules thy;

     val defs = mk_deftab thy;

     val gr = new_node ("<Top>", (NONE, module, ""))

       (List.foldl (fn ((gr, (tab1, tab2)), (gr', (tab1', tab2'))) =>

         (Graph.merge (fn ((_, module, _), (_, module', _)) =>

            module = module') (gr, gr'),

          (merge_nametabs (tab1, tab1'), merge_nametabs (tab2, tab2')))) emptygr

            (map (fn s => case Symtab.lookup graphs s of

                 NONE => error ("Undefined code module: " ^ s)

               | SOME gr => gr) modules))

       handle Graph.DUP k => error ("Duplicate code for " ^ k);

     fun expand (t as Abs _) = t

       | expand t = (case fastype_of t of

           Type ("fun", [T, U]) => Abs ("x", T, t $ Bound 0) | _ => t);

     val (ps, gr') = fold_map (fn (s, t) => fn gr => apfst (pair s)

       (invoke_codegen thy defs "<Top>" module false t gr))

         (map (apsnd (expand o preprocess_term thy o prep_term thy)) xs) gr;

     val code = map_filter

       (fn ("", _) => NONE

         | (s', p) => SOME (string_of (Pretty.block

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

     val code' = space_implode "\n\n" code ^ "\n\n";

     val code'' =

       map_filter (fn (name, s) =>

           if member (op =) (!mode) "library" andalso name = module andalso null code

           then NONE

           else SOME (name, mk_struct name s))

         ((if null code then I

           else add_to_module module code')

            (output_code (fst gr') (if_library "" module) ["<Top>"]))

   in

     (code'', del_nodes ["<Top>"] gr')

   end;

 val generate_code_i = gen_generate_code Sign.cert_term;

 val generate_code =

   gen_generate_code (Syntax.read_term o ProofContext.allow_dummies o ProofContext.init_global);

 (**** Reflection ****)

 val strip_tname = implode o tl o explode;

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

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

   [str "]"]);

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

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

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

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

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

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

 fun mk_term_of gr module p (TVar ((s, i), _)) = str

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

   | mk_term_of gr module p (TFree (s, _)) = str (strip_tname s ^ "F")

   | mk_term_of gr module p (Type (s, Ts)) = (if p then parens else I)

       (Pretty.block (separate (Pretty.brk 1)

         (str (mk_qual_id module

           (get_type_id' (fn s' => "term_of_" ^ s') gr s)) ::

         maps (fn T =>

           [mk_term_of gr module true T, mk_type true T]) Ts)));

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

 fun mk_gen gr module p xs a (TVar ((s, i), _)) = str

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

   | mk_gen gr module p xs a (TFree (s, _)) = str (strip_tname s ^ "G")

   | mk_gen gr module p xs a (Type (tyc as (s, Ts))) = (if p then parens else I)

       (Pretty.block (separate (Pretty.brk 1)

         (str (mk_qual_id module (get_type_id' (fn s' => "gen_" ^ s') gr s) ^

           (if member (op =) xs s then "'" else "")) ::

          (case tyc of

             ("fun", [T, U]) =>

               [mk_term_of gr module true T, mk_type true T,

                mk_gen gr module true xs a U, mk_type true U]

           | _ => maps (fn T =>

               [mk_gen gr module true xs a T, mk_type true T]) Ts) @

          (if member (op =) xs s then [str a] else []))));

 val test_fn : (int -> term list option) Unsynchronized.ref =

   Unsynchronized.ref (fn _ => NONE);

 fun test_term ctxt report t =

   let

     val thy = ProofContext.theory_of ctxt;

     val (code, gr) = setmp_CRITICAL mode ["term_of", "test"]

       (generate_code_i thy [] "Generated") [("testf", t)];

     val Ts = map snd (fst (strip_abs t));

     val args = map_index (fn (i, T) => ("arg" ^ string_of_int i, T)) Ts;

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

       cat_lines (map snd code) ^

       "\nopen Generated;\n\n" ^ string_of

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

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

           mk_let (map (fn (s, T) =>

               (mk_tuple [str s, str (s ^ "_t")],

                Pretty.block [mk_gen gr "Generated" false [] "" T, Pretty.brk 1,

                  str "i"])) args)

             (Pretty.block [str "if ",

               mk_app false (str "testf") (map (str o fst) args),

               Pretty.brk 1, str "then NONE",

               Pretty.brk 1, str "else ",

               Pretty.block [str "SOME ", Pretty.block (str "[" ::

                 Pretty.commas (map (fn (s, _) => str (s ^ "_t ()")) args) @

                   [str "]"])]]),

           str ");"]) ^

       "\n\nend;\n";

     val _ = ML_Context.eval_text_in (SOME ctxt) false Position.none s;

     val dummy_report = ([], false)

   in (fn size => (! test_fn size, dummy_report)) end;

 (**** Evaluator for terms ****)

 val eval_result = Unsynchronized.ref (fn () => Bound 0);

 fun eval_term thy t =

   let

     val ctxt = ProofContext.init_global thy;

     val e =

       let

         val _ = (null (Term.add_tvars t []) andalso null (Term.add_tfrees t [])) orelse

           error "Term to be evaluated contains type variables";

         val _ = (null (Term.add_vars t []) andalso null (Term.add_frees t [])) orelse

           error "Term to be evaluated contains variables";

         val (code, gr) = setmp_CRITICAL mode ["term_of"]

           (generate_code_i thy [] "Generated")

           [("result", Abs ("x", TFree ("'a", []), t))];

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

           cat_lines (map snd code) ^

           "\nopen Generated;\n\n" ^ string_of

             (Pretty.block [str "val () = Codegen.eval_result := (fn () =>",

               Pretty.brk 1,

               mk_app false (mk_term_of gr "Generated" false (fastype_of t))

                 [str "(result ())"],

               str ");"]) ^

           "\n\nend;\n";

         val _ = NAMED_CRITICAL "codegen" (fn () =>   (* FIXME ??? *)

           ML_Context.eval_text_in (SOME ctxt) false Position.none s);

       in !eval_result end;

   in e () end;

 val (_, evaluation_conv) = Context.>>> (Context.map_theory_result

   (Thm.add_oracle (Binding.name "evaluation", fn ct =>

     let

       val thy = Thm.theory_of_cterm ct;

       val t = Thm.term_of ct;

     in Thm.cterm_of thy (Logic.mk_equals (t, eval_term thy t)) end)));

 (**** Interface ****)

 fun parse_mixfix rd s =

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

      (   $$ "_" >> K Arg

       || $$ "?" >> K Ignore

       || $$ "\\<module>" >> K Module

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

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

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

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

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

       || Scan.repeat1

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

             || Scan.unless ($$ "_" || $$ "?" || $$ "\\<module>" || $$ "/" || $$ "{" |-- $$ "*")

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

        (Symbol.explode s) of

      (p, []) => p

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

 val _ = List.app Keyword.keyword ["attach", "file", "contains"];

 fun strip_whitespace s = implode (fst (take_suffix (fn c => c = "\n" orelse c = " ")

   (snd (take_prefix (fn c => c = "\n" orelse c = " ") (explode s))))) ^ "\n";

 val parse_attach = Scan.repeat (Parse.$$$ "attach" |--

   Scan.optional (Parse.$$$ "(" |-- Parse.xname --| Parse.$$$ ")") "" --

     (Parse.verbatim >> strip_whitespace));

 val _ =

   Outer_Syntax.command "types_code"

   "associate types with target language types" Keyword.thy_decl

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

      (fn xs => Toplevel.theory (fn thy => fold (assoc_type o

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

          (Syntax.read_typ_global thy) mfx, aux)))) xs thy)));

 val _ =

   Outer_Syntax.command "consts_code"

   "associate constants with target language code" Keyword.thy_decl

     (Scan.repeat1

        (Parse.term --|

         Parse.$$$ "(" -- Parse.string --| Parse.$$$ ")" -- parse_attach) >>

      (fn xs => Toplevel.theory (fn thy => fold (assoc_const o

        (fn ((const, mfx), aux) =>

          (const, (parse_mixfix (Syntax.read_term_global thy) mfx, aux)))) xs thy)));

 fun parse_code lib =

   Scan.optional (Parse.$$$ "(" |-- Parse.enum "," Parse.xname --| Parse.$$$ ")") (!mode) --

   (if lib then Scan.optional Parse.name "" else Parse.name) --

   Scan.option (Parse.$$$ "file" |-- Parse.name) --

   (if lib then Scan.succeed []

    else Scan.optional (Parse.$$$ "imports" |-- Scan.repeat1 Parse.name) []) --|

   Parse.$$$ "contains" --

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

    || Scan.repeat1 (Parse.term >> pair "")) >>

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

     let

       val mode'' = (if lib then insert (op =) "library" else I) (remove (op =) "library" mode');

       val (code, gr) = setmp_CRITICAL mode mode'' (generate_code thy modules module) xs;

       val thy' = thy |> Context.theory_map (ML_Context.exec (fn () =>

         (case opt_fname of

           NONE => ML_Context.eval_text false Position.none (cat_lines (map snd code))

         | SOME fname =>

             if lib then app (fn (name, s) => File.write

                 (Path.append (Path.explode fname) (Path.basic (name ^ ".ML"))) s)

               (("ROOT", implode (map (fn (name, _) =>

                   "use \"" ^ name ^ ".ML\";\n") code)) :: code)

             else File.write (Path.explode fname) (snd (hd code)))));

     in

       if lib then thy'

       else map_modules (Symtab.update (module, gr)) thy'

     end));

 val setup = add_codegen "default" default_codegen

   #> add_tycodegen "default" default_tycodegen

   #> add_preprocessor unfold_preprocessor;

 val _ =

   Outer_Syntax.command "code_library"

     "generates code for terms (one structure for each theory)" Keyword.thy_decl

     (parse_code true);

 val _ =

   Outer_Syntax.command "code_module"

     "generates code for terms (single structure, incremental)" Keyword.thy_decl

     (parse_code false);

 end;