src/Pure/codegen.ML
author wenzelm
Sat Sep 01 00:20:44 2001 +0200 (2001-09-01)
changeset 11546 2b3f02227c35
parent 11539 0f17da240450
child 12123 739eba13e2cd
permissions -rw-r--r--
tuned;
     1 (*  Title:      Pure/codegen.ML
     2     ID:         $Id$
     3     Author:     Stefan Berghofer, TU Muenchen
     4     License:    GPL (GNU GENERAL PUBLIC LICENSE)
     5 
     6 Generic code generator.
     7 *)
     8 
     9 signature CODEGEN =
    10 sig
    11   val quiet_mode : bool ref
    12   val message : string -> unit
    13 
    14   datatype mixfix =
    15       Arg
    16     | Ignore
    17     | Pretty of Pretty.T
    18     | Term of term;
    19 
    20   val add_codegen: string ->
    21     (theory -> (exn option * string) Graph.T -> string -> bool -> term ->
    22     ((exn option * string) Graph.T * Pretty.T) option) -> theory -> theory
    23   val print_codegens: theory -> unit
    24   val generate_code: theory -> (string * string) list -> string
    25   val generate_code_i: theory -> (string * term) list -> string
    26   val assoc_consts: (xstring * string option * mixfix list) list -> theory -> theory
    27   val assoc_consts_i: (xstring * typ option * mixfix list) list -> theory -> theory
    28   val assoc_types: (xstring * string) list -> theory -> theory
    29   val get_assoc_code: theory -> string -> typ -> mixfix list option
    30   val get_assoc_types: theory -> (string * string) list
    31   val invoke_codegen: theory -> (exn option * string) Graph.T ->
    32     string -> bool -> term -> (exn option * string) Graph.T * Pretty.T
    33   val mk_const_id: Sign.sg -> string -> string
    34   val mk_type_id: Sign.sg -> string -> string
    35   val rename_term: term -> term
    36   val get_defn: theory -> string -> typ -> ((term list * term) * int option) option
    37   val is_instance: theory -> typ -> typ -> bool
    38   val parens: Pretty.T -> Pretty.T
    39   val mk_app: bool -> Pretty.T -> Pretty.T list -> Pretty.T
    40   val eta_expand: term -> term list -> int -> term
    41   val parsers: OuterSyntax.parser list
    42   val setup: (theory -> theory) list
    43 end;
    44 
    45 structure Codegen : CODEGEN =
    46 struct
    47 
    48 val quiet_mode = ref true;
    49 fun message s = if !quiet_mode then () else writeln s;
    50 
    51 (**** Mixfix syntax ****)
    52 
    53 datatype mixfix =
    54     Arg
    55   | Ignore
    56   | Pretty of Pretty.T
    57   | Term of term;
    58 
    59 fun is_arg Arg = true
    60   | is_arg Ignore = true
    61   | is_arg _ = false;
    62 
    63 fun terms_of [] = []
    64   | terms_of (Term t :: ms) = t :: terms_of ms
    65   | terms_of (_ :: ms) = terms_of ms;
    66 
    67 val num_args = length o filter is_arg;
    68 
    69 
    70 (**** theory data ****)
    71 
    72 (* data kind 'Pure/codegen' *)
    73 
    74 structure CodegenArgs =
    75 struct
    76   val name = "Pure/codegen";
    77   type T =
    78     {codegens : (string * (theory -> (exn option * string) Graph.T -> string ->
    79        bool -> term -> ((exn option * string) Graph.T * Pretty.T) option)) list,
    80      consts : ((string * typ) * mixfix list) list,
    81      types : (string * string) list};
    82 
    83   val empty = {codegens = [], consts = [], types = []};
    84   val copy = I;
    85   val prep_ext = I;
    86 
    87   fun merge ({codegens = codegens1, consts = consts1, types = types1},
    88              {codegens = codegens2, consts = consts2, types = types2}) =
    89     {codegens = rev (merge_alists (rev codegens1) (rev codegens2)),
    90      consts   = merge_alists consts1 consts2,
    91      types    = merge_alists types1 types2};
    92 
    93   fun print sg (cs:T) = Pretty.writeln
    94     (Pretty.strs ("code generators:" :: map fst (#codegens cs)));
    95 end;
    96 
    97 structure CodegenData = TheoryDataFun(CodegenArgs);
    98 val print_codegens = CodegenData.print;
    99 
   100 
   101 (**** add new code generator to theory ****)
   102 
   103 fun add_codegen name f thy =
   104   let val {codegens, consts, types} = CodegenData.get thy
   105   in (case assoc (codegens, name) of
   106       None => CodegenData.put {codegens = (name, f)::codegens,
   107         consts = consts, types = types} thy
   108     | Some _ => error ("Code generator " ^ name ^ " already declared"))
   109   end;
   110 
   111 
   112 (**** associate constants with target language code ****)
   113 
   114 fun gen_assoc_consts prep_type xs thy = foldl (fn (thy, (s, tyopt, syn)) =>
   115   let
   116     val sg = sign_of thy;
   117     val {codegens, consts, types} = CodegenData.get thy;
   118     val cname = Sign.intern_const sg s;
   119   in
   120     (case Sign.const_type sg cname of
   121        Some T =>
   122          let val T' = (case tyopt of
   123                 None => T
   124               | Some ty =>
   125                   let val U = prep_type sg ty
   126                   in if Type.typ_instance (Sign.tsig_of sg, U, T) then U
   127                     else error ("Illegal type constraint for constant " ^ cname)
   128                   end)
   129          in (case assoc (consts, (cname, T')) of
   130              None => CodegenData.put {codegens = codegens,
   131                consts = ((cname, T'), syn) :: consts, types = types} thy
   132            | Some _ => error ("Constant " ^ cname ^ " already associated with code"))
   133          end
   134      | _ => error ("Not a constant: " ^ s))
   135   end) (thy, xs);
   136 
   137 val assoc_consts_i = gen_assoc_consts (K I);
   138 val assoc_consts = gen_assoc_consts (fn sg => typ_of o read_ctyp sg);
   139 
   140 (**** associate types with target language types ****)
   141 
   142 fun assoc_types xs thy = foldl (fn (thy, (s, syn)) =>
   143   let
   144     val {codegens, consts, types} = CodegenData.get thy;
   145     val tc = Sign.intern_tycon (sign_of thy) s
   146   in
   147     (case assoc (types, tc) of
   148        None => CodegenData.put {codegens = codegens, consts = consts,
   149          types = (tc, syn) :: types} thy
   150      | Some _ => error ("Type " ^ tc ^ " already associated with code"))
   151   end) (thy, xs);
   152 
   153 fun get_assoc_types thy = #types (CodegenData.get thy);
   154 
   155 
   156 (**** retrieve definition of constant ****)
   157 
   158 fun is_instance thy T1 T2 =
   159   Type.typ_instance (Sign.tsig_of (sign_of thy), T1, Type.varifyT T2);
   160 
   161 fun get_assoc_code thy s T = apsome snd (find_first (fn ((s', T'), _) =>
   162   s = s' andalso is_instance thy T T') (#consts (CodegenData.get thy)));
   163 
   164 fun get_defn thy s T =
   165   let
   166     val axms = flat (map (Symtab.dest o #axioms o Theory.rep_theory)
   167       (thy :: Theory.ancestors_of thy));
   168     val defs = mapfilter (fn (_, t) =>
   169       (let
   170          val (lhs, rhs) = Logic.dest_equals t;
   171          val (c, args) = strip_comb lhs;
   172          val (s', T') = dest_Const c
   173        in if s=s' then Some (T', (args, rhs)) else None end) handle TERM _ =>
   174          None) axms;
   175     val i = find_index (is_instance thy T o fst) defs
   176   in
   177     if i>=0 then Some (snd (nth_elem (i, defs)),
   178       if length defs = 1 then None else Some i)
   179     else None
   180   end;
   181 
   182 
   183 (**** make valid ML identifiers ****)
   184 
   185 fun gen_mk_id kind rename sg s =
   186   let
   187     val (xs as x::_) = explode (rename (space_implode "_"
   188       (NameSpace.unpack (Sign.cond_extern sg kind s))));
   189     fun check_str [] = ""
   190       | check_str (x::xs) =
   191           (if Symbol.is_letter x orelse Symbol.is_digit x orelse x="_" then x
   192            else "_" ^ string_of_int (ord x)) ^ check_str xs
   193   in
   194     (if not (Symbol.is_letter x) then "id" else "") ^ check_str xs
   195   end;
   196 
   197 val mk_const_id = gen_mk_id Sign.constK I;
   198 val mk_type_id = gen_mk_id Sign.typeK
   199   (fn s => if s mem ThmDatabase.ml_reserved then s ^ "_type" else s);
   200 
   201 fun rename_term t =
   202   let
   203     val names = add_term_names (t, map (fst o fst o dest_Var) (term_vars t));
   204     val clash = names inter ThmDatabase.ml_reserved;
   205     val ps = clash ~~ variantlist (clash, names);
   206 
   207     fun rename (Var ((a, i), T)) = Var ((if_none (assoc (ps, a)) a, i), T)
   208       | rename (Free (a, T)) = Free (if_none (assoc (ps, a)) a, T)
   209       | rename (Abs (s, T, t)) = Abs (s, T, rename t)
   210       | rename (t $ u) = rename t $ rename u
   211       | rename t = t;
   212   in
   213     rename t
   214   end;
   215 
   216 
   217 (**** invoke suitable code generator for term t ****)
   218 
   219 fun invoke_codegen thy gr dep brack t = (case get_first
   220    (fn (_, f) => f thy gr dep brack t) (#codegens (CodegenData.get thy)) of
   221       None => error ("Unable to generate code for term:\n" ^
   222         Sign.string_of_term (sign_of thy) t ^ "\nrequired by:\n" ^
   223         commas (Graph.all_succs gr [dep]))
   224     | Some x => x)
   225 
   226 
   227 (**** code generator for mixfix expressions ****)
   228 
   229 fun parens p = Pretty.block [Pretty.str "(", p, Pretty.str ")"];
   230 
   231 fun pretty_fn [] p = [p]
   232   | pretty_fn (x::xs) p = Pretty.str ("fn " ^ x ^ " =>") ::
   233       Pretty.brk 1 :: pretty_fn xs p;
   234 
   235 fun pretty_mixfix [] [] _ = []
   236   | pretty_mixfix (Arg :: ms) (p :: ps) qs = p :: pretty_mixfix ms ps qs
   237   | pretty_mixfix (Ignore :: ms) (p :: ps) qs = pretty_mixfix ms ps qs
   238   | pretty_mixfix (Pretty p :: ms) ps qs = p :: pretty_mixfix ms ps qs
   239   | pretty_mixfix (Term _ :: ms) ps (q :: qs) = q :: pretty_mixfix ms ps qs;
   240 
   241 
   242 (**** default code generator ****)
   243 
   244 fun eta_expand t ts i =
   245   let
   246     val (Ts, _) = strip_type (fastype_of t);
   247     val j = i - length ts
   248   in
   249     foldr (fn (T, t) => Abs ("x", T, t))
   250       (take (j, Ts), list_comb (t, ts @ map Bound (j-1 downto 0)))
   251   end;
   252 
   253 fun mk_app _ p [] = p
   254   | mk_app brack p ps = if brack then
   255        Pretty.block (Pretty.str "(" ::
   256          separate (Pretty.brk 1) (p :: ps) @ [Pretty.str ")"])
   257      else Pretty.block (separate (Pretty.brk 1) (p :: ps));
   258 
   259 fun new_names t xs = variantlist (xs,
   260   map (fst o fst o dest_Var) (term_vars t) union
   261   add_term_names (t, ThmDatabase.ml_reserved));
   262 
   263 fun new_name t x = hd (new_names t [x]);
   264 
   265 fun default_codegen thy gr dep brack t =
   266   let
   267     val (u, ts) = strip_comb t;
   268     fun mapcode brack' gr ts = foldl_map
   269       (fn (gr, t) => invoke_codegen thy gr dep brack' t) (gr, ts)
   270 
   271   in (case u of
   272       Var ((s, i), _) =>
   273         let val (gr', ps) = mapcode true gr ts
   274         in Some (gr', mk_app brack (Pretty.str (s ^
   275            (if i=0 then "" else string_of_int i))) ps)
   276         end
   277 
   278     | Free (s, _) =>
   279         let val (gr', ps) = mapcode true gr ts
   280         in Some (gr', mk_app brack (Pretty.str s) ps) end
   281 
   282     | Const (s, T) =>
   283       (case get_assoc_code thy s T of
   284          Some ms =>
   285            let val i = num_args ms
   286            in if length ts < i then
   287                default_codegen thy gr dep brack (eta_expand u ts i)
   288              else
   289                let
   290                  val ts1 = take (i, ts);
   291                  val ts2 = drop (i, ts);
   292                  val (gr1, ps1) = mapcode false gr ts1;
   293                  val (gr2, ps2) = mapcode true gr1 ts2;
   294                  val (gr3, ps3) = mapcode false gr2 (terms_of ms);
   295                in
   296                  Some (gr3, mk_app brack (Pretty.block (pretty_mixfix ms ps1 ps3)) ps2)
   297                end
   298            end
   299        | None => (case get_defn thy s T of
   300            None => None
   301          | Some ((args, rhs), k) =>
   302              let
   303                val id = mk_const_id (sign_of thy) s ^ (case k of
   304                  None => "" | Some i => "_def" ^ string_of_int i);
   305                val (gr', ps) = mapcode true gr ts;
   306              in
   307                Some (Graph.add_edge (id, dep) gr' handle Graph.UNDEF _ =>
   308                  let
   309                    val _ = message ("expanding definition of " ^ s);
   310                    val (Ts, _) = strip_type T;
   311                    val (args', rhs') =
   312                      if not (null args) orelse null Ts then (args, rhs) else
   313                        let val v = Free (new_name rhs "x", hd Ts)
   314                        in ([v], betapply (rhs, v)) end;
   315                    val (gr1, p) = invoke_codegen thy (Graph.add_edge (id, dep)
   316                      (Graph.new_node (id, (None, "")) gr')) id false rhs';
   317                    val (gr2, xs) = mapcode false gr1 args';
   318                  in Graph.map_node id (K (None, Pretty.string_of (Pretty.block
   319                    (Pretty.str (if null args' then "val " else "fun ") ::
   320                     separate (Pretty.brk 1) (Pretty.str id :: xs) @
   321                     [Pretty.str " =", Pretty.brk 1, p, Pretty.str ";"])) ^ "\n\n")) gr2
   322                  end, mk_app brack (Pretty.str id) ps)
   323              end))
   324 
   325     | Abs _ =>
   326       let
   327         val (bs, Ts) = ListPair.unzip (strip_abs_vars u);
   328         val t = strip_abs_body u
   329         val bs' = new_names t bs;
   330         val (gr1, ps) = mapcode true gr ts;
   331         val (gr2, p) = invoke_codegen thy gr1 dep false
   332           (subst_bounds (map Free (rev (bs' ~~ Ts)), t));
   333       in
   334         Some (gr2, mk_app brack (Pretty.block (Pretty.str "(" :: pretty_fn bs' p @
   335           [Pretty.str ")"])) ps)
   336       end
   337 
   338     | _ => None)
   339   end;
   340 
   341 
   342 fun output_code gr xs = implode (map (snd o Graph.get_node gr)
   343   (rev (Graph.all_preds gr xs)));
   344 
   345 fun gen_generate_code prep_term thy = Pretty.setmp_margin 80 (fn xs =>
   346   let
   347     val sg = sign_of thy;
   348     val gr = Graph.new_node ("<Top>", (None, "")) Graph.empty;
   349     val (gr', ps) = foldl_map (fn (gr, (s, t)) => apsnd (pair s)
   350       (invoke_codegen thy gr "<Top>" false t)) (gr, map (apsnd (prep_term sg)) xs)
   351   in
   352     "structure Generated =\nstruct\n\n" ^
   353     output_code gr' ["<Top>"] ^
   354     space_implode "\n\n" (map (fn (s', p) => Pretty.string_of (Pretty.block
   355       [Pretty.str ("val " ^ s' ^ " ="), Pretty.brk 1, p, Pretty.str ";"])) ps) ^
   356     "\n\nend;\n\nopen Generated;\n"
   357   end);
   358 
   359 val generate_code_i = gen_generate_code (K I);
   360 val generate_code = gen_generate_code
   361   (fn sg => term_of o read_cterm sg o rpair TypeInfer.logicT);
   362 
   363 fun parse_mixfix rd s =
   364   (case Scan.finite Symbol.stopper (Scan.repeat
   365      (   $$ "_" >> K Arg
   366       || $$ "?" >> K Ignore
   367       || $$ "/" |-- Scan.repeat ($$ " ") >> (Pretty o Pretty.brk o length)
   368       || $$ "{" |-- $$ "*" |-- Scan.repeat1
   369            (   $$ "'" |-- Scan.one Symbol.not_eof
   370             || Scan.unless ($$ "*" -- $$ "}") (Scan.one Symbol.not_eof)) --|
   371          $$ "*" --| $$ "}" >> (Term o rd o implode)
   372       || Scan.repeat1
   373            (   $$ "'" |-- Scan.one Symbol.not_eof
   374             || Scan.unless ($$ "_" || $$ "?" || $$ "/" || $$ "{" |-- $$ "*")
   375                  (Scan.one Symbol.not_eof)) >> (Pretty o Pretty.str o implode)))
   376        (Symbol.explode s) of
   377      (p, []) => p
   378    | _ => error ("Malformed annotation: " ^ quote s));
   379 
   380 structure P = OuterParse and K = OuterSyntax.Keyword;
   381 
   382 val assoc_typeP =
   383   OuterSyntax.command "types_code"
   384   "associate types with target language types" K.thy_decl
   385     (Scan.repeat1 (P.xname --| P.$$$ "(" -- P.string --| P.$$$ ")") >>
   386      (Toplevel.theory o assoc_types));
   387 
   388 val assoc_constP =
   389   OuterSyntax.command "consts_code"
   390   "associate constants with target language code" K.thy_decl
   391     (Scan.repeat1
   392        (P.xname -- (Scan.option (P.$$$ "::" |-- P.string)) --|
   393         P.$$$ "(" -- P.string --| P.$$$ ")") >>
   394      (fn xs => Toplevel.theory (fn thy => assoc_consts
   395        (map (fn ((name, optype), mfx) => (name, optype, parse_mixfix
   396          (term_of o read_cterm (sign_of thy) o rpair TypeInfer.logicT) mfx))
   397            xs) thy)));
   398 
   399 val generate_codeP =
   400   OuterSyntax.command "generate_code" "generates code for terms" K.thy_decl
   401     (Scan.option (P.$$$ "(" |-- P.string --| P.$$$ ")") --
   402      Scan.repeat1 (P.name --| P.$$$ "=" -- P.string) >>
   403      (fn (opt_fname, xs) => Toplevel.theory (fn thy =>
   404         ((case opt_fname of
   405             None => use_text Context.ml_output false
   406           | Some fname => File.write (Path.unpack fname))
   407               (generate_code thy xs); thy))));
   408 
   409 val parsers = [assoc_typeP, assoc_constP, generate_codeP];
   410 
   411 val setup = [CodegenData.init, add_codegen "default" default_codegen];
   412 
   413 end;
   414 
   415 OuterSyntax.add_parsers Codegen.parsers;