(* Title: HOL/datatype_codegen.ML
ID: $Id$
Author: Stefan Berghofer, TU Muenchen
Code generator for inductive datatypes.
*)
signature DATATYPE_CODEGEN =
sig
val setup: theory -> theory
end;
structure DatatypeCodegen : DATATYPE_CODEGEN =
struct
open Codegen;
fun mk_tuple [p] = p
| mk_tuple ps = Pretty.block (Pretty.str "(" ::
List.concat (separate [Pretty.str ",", Pretty.brk 1] (map single ps)) @
[Pretty.str ")"]);
(**** datatype definition ****)
(* find shortest path to constructor with no recursive arguments *)
fun find_nonempty (descr: DatatypeAux.descr) is i =
let
val (_, _, constrs) = valOf (AList.lookup (op =) descr i);
fun arg_nonempty (_, DatatypeAux.DtRec i) = if i mem is then NONE
else Option.map (curry op + 1 o snd) (find_nonempty descr (i::is) i)
| arg_nonempty _ = SOME 0;
fun max xs = Library.foldl
(fn (NONE, _) => NONE
| (SOME i, SOME j) => SOME (Int.max (i, j))
| (_, NONE) => NONE) (SOME 0, xs);
val xs = sort (int_ord o pairself snd)
(List.mapPartial (fn (s, dts) => Option.map (pair s)
(max (map (arg_nonempty o DatatypeAux.strip_dtyp) dts))) constrs)
in case xs of [] => NONE | x :: _ => SOME x end;
fun add_dt_defs thy defs dep module gr (descr: DatatypeAux.descr) =
let
val sg = sign_of thy;
val tab = DatatypePackage.get_datatypes thy;
val descr' = List.filter (can (map DatatypeAux.dest_DtTFree o #2 o snd)) descr;
val rtnames = map (#1 o snd) (List.filter (fn (_, (_, _, cs)) =>
exists (exists DatatypeAux.is_rec_type o snd) cs) descr');
val (_, (tname, _, _)) :: _ = descr';
val node_id = tname ^ " (type)";
val module' = if_library (thyname_of_type tname thy) module;
fun mk_dtdef gr prfx [] = (gr, [])
| mk_dtdef gr prfx ((_, (tname, dts, cs))::xs) =
let
val tvs = map DatatypeAux.dest_DtTFree dts;
val sorts = map (rpair []) tvs;
val cs' = map (apsnd (map (DatatypeAux.typ_of_dtyp descr sorts))) cs;
val (gr', (_, type_id)) = mk_type_id module' tname gr;
val (gr'', ps) =
foldl_map (fn (gr, (cname, cargs)) =>
foldl_map (invoke_tycodegen thy defs node_id module' false)
(gr, cargs) |>>>
mk_const_id module' cname) (gr', cs');
val (gr''', rest) = mk_dtdef gr'' "and " xs
in
(gr''',
Pretty.block (Pretty.str prfx ::
(if null tvs then [] else
[mk_tuple (map Pretty.str tvs), Pretty.str " "]) @
[Pretty.str (type_id ^ " ="), Pretty.brk 1] @
List.concat (separate [Pretty.brk 1, Pretty.str "| "]
(map (fn (ps', (_, cname)) => [Pretty.block
(Pretty.str cname ::
(if null ps' then [] else
List.concat ([Pretty.str " of", Pretty.brk 1] ::
separate [Pretty.str " *", Pretty.brk 1]
(map single ps'))))]) ps))) :: rest)
end;
fun mk_term_of_def gr prfx [] = []
| mk_term_of_def gr prfx ((_, (tname, dts, cs)) :: xs) =
let
val tvs = map DatatypeAux.dest_DtTFree dts;
val sorts = map (rpair []) tvs;
val cs' = map (apsnd (map (DatatypeAux.typ_of_dtyp descr sorts))) cs;
val dts' = map (DatatypeAux.typ_of_dtyp descr sorts) dts;
val T = Type (tname, dts');
val rest = mk_term_of_def gr "and " xs;
val (_, eqs) = foldl_map (fn (prfx, (cname, Ts)) =>
let val args = map (fn i =>
Pretty.str ("x" ^ string_of_int i)) (1 upto length Ts)
in (" | ", Pretty.blk (4,
[Pretty.str prfx, mk_term_of gr module' false T, Pretty.brk 1,
if null Ts then Pretty.str (snd (get_const_id cname gr))
else parens (Pretty.block
[Pretty.str (snd (get_const_id cname gr)),
Pretty.brk 1, mk_tuple args]),
Pretty.str " =", Pretty.brk 1] @
List.concat (separate [Pretty.str " $", Pretty.brk 1]
([Pretty.str ("Const (\"" ^ cname ^ "\","), Pretty.brk 1,
mk_type false (Ts ---> T), Pretty.str ")"] ::
map (fn (x, U) => [Pretty.block [mk_term_of gr module' false U,
Pretty.brk 1, x]]) (args ~~ Ts)))))
end) (prfx, cs')
in eqs @ rest end;
fun mk_gen_of_def gr prfx [] = []
| mk_gen_of_def gr prfx ((i, (tname, dts, cs)) :: xs) =
let
val tvs = map DatatypeAux.dest_DtTFree dts;
val sorts = map (rpair []) tvs;
val (cs1, cs2) =
List.partition (exists DatatypeAux.is_rec_type o snd) cs;
val SOME (cname, _) = find_nonempty descr [i] i;
fun mk_delay p = Pretty.block
[Pretty.str "fn () =>", Pretty.brk 1, p];
fun mk_constr s b (cname, dts) =
let
val gs = map (fn dt => mk_app false (mk_gen gr module' false rtnames s
(DatatypeAux.typ_of_dtyp descr sorts dt))
[Pretty.str (if b andalso DatatypeAux.is_rec_type dt then "0"
else "j")]) dts;
val (_, id) = get_const_id cname gr
in case gs of
_ :: _ :: _ => Pretty.block
[Pretty.str id, Pretty.brk 1, mk_tuple gs]
| _ => mk_app false (Pretty.str id) (map parens gs)
end;
fun mk_choice [c] = mk_constr "(i-1)" false c
| mk_choice cs = Pretty.block [Pretty.str "one_of",
Pretty.brk 1, Pretty.blk (1, Pretty.str "[" ::
List.concat (separate [Pretty.str ",", Pretty.fbrk]
(map (single o mk_delay o mk_constr "(i-1)" false) cs)) @
[Pretty.str "]"]), Pretty.brk 1, Pretty.str "()"];
val gs = map (Pretty.str o suffix "G" o strip_tname) tvs;
val gen_name = "gen_" ^ snd (get_type_id tname gr)
in
Pretty.blk (4, separate (Pretty.brk 1)
(Pretty.str (prfx ^ gen_name ^
(if null cs1 then "" else "'")) :: gs @
(if null cs1 then [] else [Pretty.str "i"]) @
[Pretty.str "j"]) @
[Pretty.str " =", Pretty.brk 1] @
(if not (null cs1) andalso not (null cs2)
then [Pretty.str "frequency", Pretty.brk 1,
Pretty.blk (1, [Pretty.str "[",
mk_tuple [Pretty.str "i", mk_delay (mk_choice cs1)],
Pretty.str ",", Pretty.fbrk,
mk_tuple [Pretty.str "1", mk_delay (mk_choice cs2)],
Pretty.str "]"]), Pretty.brk 1, Pretty.str "()"]
else if null cs2 then
[Pretty.block [Pretty.str "(case", Pretty.brk 1,
Pretty.str "i", Pretty.brk 1, Pretty.str "of",
Pretty.brk 1, Pretty.str "0 =>", Pretty.brk 1,
mk_constr "0" true (cname, valOf (AList.lookup (op =) cs cname)),
Pretty.brk 1, Pretty.str "| _ =>", Pretty.brk 1,
mk_choice cs1, Pretty.str ")"]]
else [mk_choice cs2])) ::
(if null cs1 then []
else [Pretty.blk (4, separate (Pretty.brk 1)
(Pretty.str ("and " ^ gen_name) :: gs @ [Pretty.str "i"]) @
[Pretty.str " =", Pretty.brk 1] @
separate (Pretty.brk 1) (Pretty.str (gen_name ^ "'") :: gs @
[Pretty.str "i", Pretty.str "i"]))]) @
mk_gen_of_def gr "and " xs
end
in
(add_edge_acyclic (node_id, dep) gr
handle Graph.CYCLES _ => gr) handle Graph.UNDEF _ =>
let
val gr1 = add_edge (node_id, dep)
(new_node (node_id, (NONE, "", "")) gr);
val (gr2, dtdef) = mk_dtdef gr1 "datatype " descr';
in
map_node node_id (K (NONE, module',
Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk dtdef @
[Pretty.str ";"])) ^ "\n\n" ^
(if "term_of" mem !mode then
Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk
(mk_term_of_def gr2 "fun " descr') @ [Pretty.str ";"])) ^ "\n\n"
else "") ^
(if "test" mem !mode then
Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk
(mk_gen_of_def gr2 "fun " descr') @ [Pretty.str ";"])) ^ "\n\n"
else ""))) gr2
end
end;
(**** case expressions ****)
fun pretty_case thy defs gr dep module brack constrs (c as Const (_, T)) ts =
let val i = length constrs
in if length ts <= i then
invoke_codegen thy defs dep module brack (gr, eta_expand c ts (i+1))
else
let
val ts1 = Library.take (i, ts);
val t :: ts2 = Library.drop (i, ts);
val names = foldr add_term_names
(map (fst o fst o dest_Var) (foldr add_term_vars [] ts1)) ts1;
val (Ts, dT) = split_last (Library.take (i+1, fst (strip_type T)));
fun pcase gr [] [] [] = ([], gr)
| pcase gr ((cname, cargs)::cs) (t::ts) (U::Us) =
let
val j = length cargs;
val xs = variantlist (replicate j "x", names);
val Us' = Library.take (j, fst (strip_type U));
val frees = map Free (xs ~~ Us');
val (gr0, cp) = invoke_codegen thy defs dep module false
(gr, list_comb (Const (cname, Us' ---> dT), frees));
val t' = Envir.beta_norm (list_comb (t, frees));
val (gr1, p) = invoke_codegen thy defs dep module false (gr0, t');
val (ps, gr2) = pcase gr1 cs ts Us;
in
([Pretty.block [cp, Pretty.str " =>", Pretty.brk 1, p]] :: ps, gr2)
end;
val (ps1, gr1) = pcase gr constrs ts1 Ts;
val ps = List.concat (separate [Pretty.brk 1, Pretty.str "| "] ps1);
val (gr2, p) = invoke_codegen thy defs dep module false (gr1, t);
val (gr3, ps2) = foldl_map (invoke_codegen thy defs dep module true) (gr2, ts2)
in (gr3, (if not (null ts2) andalso brack then parens else I)
(Pretty.block (separate (Pretty.brk 1)
(Pretty.block ([Pretty.str "(case ", p, Pretty.str " of",
Pretty.brk 1] @ ps @ [Pretty.str ")"]) :: ps2))))
end
end;
(**** constructors ****)
fun pretty_constr thy defs gr dep module brack args (c as Const (s, T)) ts =
let val i = length args
in if i > 1 andalso length ts < i then
invoke_codegen thy defs dep module brack (gr, eta_expand c ts i)
else
let
val id = mk_qual_id module (get_const_id s gr);
val (gr', ps) = foldl_map
(invoke_codegen thy defs dep module (i = 1)) (gr, ts);
in (case args of
_ :: _ :: _ => (gr', (if brack then parens else I)
(Pretty.block [Pretty.str id, Pretty.brk 1, mk_tuple ps]))
| _ => (gr', mk_app brack (Pretty.str id) ps))
end
end;
(**** code generators for terms and types ****)
fun datatype_codegen thy defs gr dep module brack t = (case strip_comb t of
(c as Const (s, T), ts) =>
(case Library.find_first (fn (_, {index, descr, case_name, ...}) =>
s = case_name orelse
AList.defined (op =) ((#3 o the o AList.lookup (op =) descr) index) s)
(Symtab.dest (DatatypePackage.get_datatypes thy)) of
NONE => NONE
| SOME (tname, {index, descr, ...}) =>
if is_some (get_assoc_code thy s T) then NONE else
let val SOME (_, _, constrs) = AList.lookup (op =) descr index
in (case (AList.lookup (op =) constrs s, strip_type T) of
(NONE, _) => SOME (pretty_case thy defs gr dep module brack
((#3 o the o AList.lookup (op =) descr) index) c ts)
| (SOME args, (_, Type _)) => SOME (pretty_constr thy defs
(fst (invoke_tycodegen thy defs dep module false
(gr, snd (strip_type T))))
dep module brack args c ts)
| _ => NONE)
end)
| _ => NONE);
fun datatype_tycodegen thy defs gr dep module brack (Type (s, Ts)) =
(case Symtab.lookup (DatatypePackage.get_datatypes thy) s of
NONE => NONE
| SOME {descr, ...} =>
if isSome (get_assoc_type thy s) then NONE else
let
val (gr', ps) = foldl_map
(invoke_tycodegen thy defs dep module false) (gr, Ts);
val gr'' = add_dt_defs thy defs dep module gr' descr
in SOME (gr'',
Pretty.block ((if null Ts then [] else
[mk_tuple ps, Pretty.str " "]) @
[Pretty.str (mk_qual_id module (get_type_id s gr''))]))
end)
| datatype_tycodegen _ _ _ _ _ _ _ = NONE;
val setup =
add_codegen "datatype" datatype_codegen #>
add_tycodegen "datatype" datatype_tycodegen #>
CodegenPackage.set_is_datatype
DatatypePackage.is_datatype #>
CodegenPackage.set_get_all_datatype_cons
DatatypePackage.get_all_datatype_cons #>
CodegenPackage.add_defgen
("datatype", CodegenPackage.defgen_datatype DatatypePackage.get_datatype DatatypePackage.get_datatype_cons) #>
CodegenPackage.ensure_datatype_case_consts
DatatypePackage.get_datatype_case_consts
DatatypePackage.get_case_const_data;
end;