datatype_codegen now checks type of constructor.
(* Title: HOL/datatype_codegen.ML
ID: $Id$
Author: Stefan Berghofer, TU Muenchen
License: GPL (GNU GENERAL PUBLIC LICENSE)
Code generator for inductive datatypes.
*)
signature DATATYPE_CODEGEN =
sig
val setup: (theory -> theory) list
end;
structure DatatypeCodegen : DATATYPE_CODEGEN =
struct
open Codegen;
fun mk_tuple [p] = p
| mk_tuple ps = Pretty.block (Pretty.str "(" ::
flat (separate [Pretty.str ",", Pretty.brk 1] (map single ps)) @
[Pretty.str ")"]);
(**** datatype definition ****)
fun add_dt_defs thy dep gr descr =
let
val sg = sign_of thy;
val tab = DatatypePackage.get_datatypes thy;
val descr' = filter (can (map DatatypeAux.dest_DtTFree o #2 o snd)) descr;
val (_, (_, _, (cname, _) :: _)) :: _ = descr';
val dname = mk_const_id sg cname;
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', ps) = foldl_map (fn (gr, (cname, cargs)) =>
apsnd (pair cname) (foldl_map
(invoke_tycodegen thy dname false) (gr, cargs))) (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 (mk_type_id sg tname ^ " ="), Pretty.brk 1] @
flat (separate [Pretty.brk 1, Pretty.str "| "]
(map (fn (cname, ps') => [Pretty.block
(Pretty.str (mk_const_id sg cname) ::
(if null ps' then [] else
flat ([Pretty.str " of", Pretty.brk 1] ::
separate [Pretty.str " *", Pretty.brk 1]
(map single ps'))))]) ps))) :: rest)
end
in
((Graph.add_edge_acyclic (dname, dep) gr
handle Graph.CYCLES _ => gr) handle Graph.UNDEF _ =>
let
val gr1 = Graph.add_edge (dname, dep)
(Graph.new_node (dname, (None, "")) gr);
val (gr2, dtdef) = mk_dtdef gr1 "datatype " descr';
in
Graph.map_node dname (K (None,
Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk dtdef @
[Pretty.str ";"])) ^ "\n\n")) gr2
end)
end;
(**** case expressions ****)
fun pretty_case thy gr dep brack constrs (c as Const (_, T)) ts =
let val i = length constrs
in if length ts <= i then
invoke_codegen thy dep brack (gr, eta_expand c ts (i+1))
else
let
val ts1 = take (i, ts);
val t :: ts2 = drop (i, ts);
val names = foldr add_term_names (ts1,
map (fst o fst o dest_Var) (foldr add_term_vars (ts1, [])));
val (Ts, dT) = split_last (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' = take (j, fst (strip_type U));
val frees = map Free (xs ~~ Us');
val (gr0, cp) = invoke_codegen thy dep false
(gr, list_comb (Const (cname, Us' ---> dT), frees));
val t' = Envir.beta_norm (list_comb (t, frees));
val (gr1, p) = invoke_codegen thy dep 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 = flat (separate [Pretty.brk 1, Pretty.str "| "] ps1);
val (gr2, p) = invoke_codegen thy dep false (gr1, t);
val (gr3, ps2) = foldl_map (invoke_codegen thy dep 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 gr dep brack args (c as Const (s, _)) ts =
let val i = length args
in if i > 1 andalso length ts < i then
invoke_codegen thy dep brack (gr, eta_expand c ts i)
else
let
val id = mk_const_id (sign_of thy) s;
val (gr', ps) = foldl_map (invoke_codegen thy dep (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 gr dep brack t = (case strip_comb t of
(c as Const (s, T), ts) =>
(case find_first (fn (_, {index, descr, case_name, ...}) =>
s = case_name orelse
is_some (assoc (#3 (the (assoc (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) = assoc (descr, index)
in (case (assoc (constrs, s), strip_type T) of
(None, _) => Some (pretty_case thy gr dep brack
(#3 (the (assoc (descr, index)))) c ts)
| (Some args, (_, Type _)) => Some (pretty_constr thy
(fst (invoke_tycodegen thy dep false (gr, snd (strip_type T))))
dep brack args c ts)
| _ => None)
end)
| _ => None);
fun datatype_tycodegen thy gr dep brack (Type (s, Ts)) =
(case Symtab.lookup (DatatypePackage.get_datatypes thy, s) of
None => None
| Some {descr, ...} =>
if is_some (get_assoc_type thy s) then None else
let val (gr', ps) = foldl_map
(invoke_tycodegen thy dep false) (gr, Ts)
in Some (add_dt_defs thy dep gr' descr,
Pretty.block ((if null Ts then [] else
[mk_tuple ps, Pretty.str " "]) @
[Pretty.str (mk_type_id (sign_of thy) s)]))
end)
| datatype_tycodegen _ _ _ _ _ = None;
val setup =
[add_codegen "datatype" datatype_codegen,
add_tycodegen "datatype" datatype_tycodegen];
end;