(* Title: Pure/HOL/basic_codegen.ML
ID: $Id$
Author: Stefan Berghofer, TU Muenchen
License: GPL (GNU GENERAL PUBLIC LICENSE)
Code generator for inductive datatypes and recursive functions.
*)
signature BASIC_CODEGEN =
sig
val setup: (theory -> theory) list
end;
structure BasicCodegen : BASIC_CODEGEN =
struct
open Codegen;
fun mk_poly_id thy (s, T) = mk_const_id (sign_of thy) s ^
(case get_defn thy s T of
Some (_, Some i) => "_def" ^ string_of_int i
| _ => "");
fun mk_tuple [p] = p
| mk_tuple ps = Pretty.block (Pretty.str "(" ::
flat (separate [Pretty.str ",", Pretty.brk 1] (map single ps)) @
[Pretty.str ")"]);
fun add_rec_funs thy dep (gr, eqs) =
let
fun dest_eq t =
let val (lhs, rhs) = HOLogic.dest_eq (HOLogic.dest_Trueprop
(Logic.strip_imp_concl (rename_term t)))
in
(mk_poly_id thy (dest_Const (head_of lhs)), (lhs, rhs))
end;
val eqs' = sort (string_ord o pairself fst) (map dest_eq eqs);
val (dname, _) :: _ = eqs';
fun mk_fundef fname prfx gr [] = (gr, [])
| mk_fundef fname prfx gr ((fname', (lhs, rhs))::xs) =
let
val (gr1, pl) = invoke_codegen thy gr dname false lhs;
val (gr2, pr) = invoke_codegen thy gr1 dname false rhs;
val (gr3, rest) = mk_fundef fname' "and " gr2 xs
in
(gr3, Pretty.blk (4, [Pretty.str (if fname=fname' then " | " else prfx),
pl, Pretty.str " =", Pretty.brk 1, pr]) :: rest)
end
in
(Graph.add_edge (dname, dep) gr handle Graph.UNDEF _ =>
let
val gr1 = Graph.add_edge (dname, dep)
(Graph.new_node (dname, (None, "")) gr);
val (gr2, fundef) = mk_fundef "" "fun " gr1 eqs'
in
Graph.map_node dname (K (None, Pretty.string_of (Pretty.blk (0,
separate Pretty.fbrk fundef @ [Pretty.str ";"])) ^ "\n\n")) gr2
end)
end;
(**** generate functions for datatypes specified by descr ****)
(**** (i.e. constructors and case combinators) ****)
fun mk_typ _ _ (TVar ((s, i), _)) =
Pretty.str (s ^ (if i=0 then "" else string_of_int i))
| mk_typ _ _ (TFree (s, _)) = Pretty.str s
| mk_typ sg types (Type ("fun", [T, U])) = Pretty.block [Pretty.str "(",
mk_typ sg types T, Pretty.str " ->", Pretty.brk 1,
mk_typ sg types U, Pretty.str ")"]
| mk_typ sg types (Type (s, Ts)) = Pretty.block ((if null Ts then [] else
[mk_tuple (map (mk_typ sg types) Ts), Pretty.str " "]) @
[Pretty.str (if_none (assoc (types, s)) (mk_type_id sg s))]);
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 types = get_assoc_types thy;
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 tycons = foldr add_typ_tycons (flat (map snd cs'), []) \\
("fun" :: map fst types);
val descrs = map (fn s => case Symtab.lookup (tab, s) of
None => error ("Not a datatype: " ^ s ^ "\nrequired by:\n" ^
commas (Graph.all_succs gr [dep]))
| Some info => #descr info) tycons;
val gr' = foldl (add_dt_defs thy dname) (gr, descrs);
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, cargs) => [Pretty.block
(Pretty.str (mk_const_id sg cname) ::
(if null cargs then [] else
flat ([Pretty.str " of", Pretty.brk 1] ::
separate [Pretty.str " *", Pretty.brk 1]
(map (single o mk_typ sg types) cargs))))]) cs'))) :: 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;
(**** generate code for applications of constructors and case ****)
(**** combinators for datatypes ****)
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 gr dep brack (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 (Ts, _) = strip_type (fastype_of t);
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 gr dep false
(list_comb (Const (cname, Us' ---> dT), frees));
val t' = Envir.beta_norm (list_comb (t, frees));
val (gr1, p) = invoke_codegen thy gr0 dep false 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 gr1 dep false t;
val (gr3, ps2) = foldl_map
(fn (gr, t) => invoke_codegen thy gr dep true t) (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;
fun pretty_constr thy gr dep brack args (c as Const (s, _)) ts =
let val i = length args
in if length ts < i then
invoke_codegen thy gr dep brack (eta_expand c ts i)
else
let
val id = mk_const_id (sign_of thy) s;
val (gr', ps) = foldl_map
(fn (gr, t) => invoke_codegen thy gr dep (i = 1) t) (gr, ts);
in (case args of
[] => (gr', Pretty.str id)
| [_] => (gr', mk_app brack (Pretty.str id) ps)
| _ => (gr', (if brack then parens else I) (Pretty.block
([Pretty.str id, Pretty.brk 1, Pretty.str "("] @
flat (separate [Pretty.str ",", Pretty.brk 1] (map single ps)) @
[Pretty.str ")"]))))
end
end;
fun mk_recfun thy gr dep brack s T ts eqns =
let val (gr', ps) = foldl_map
(fn (gr, t) => invoke_codegen thy gr dep true t) (gr, ts)
in
Some (add_rec_funs thy dep (gr', map (#prop o rep_thm) eqns),
mk_app brack (Pretty.str (mk_poly_id thy (s, T))) ps)
end;
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, rec_names, ...}) =>
s = case_name orelse s mem rec_names orelse
is_some (assoc (#3 (the (assoc (descr, index))), s)))
(Symtab.dest (DatatypePackage.get_datatypes thy)) of
None => None
| Some (tname, {index, descr, case_name, rec_names, rec_rewrites, ...}) =>
if is_some (get_assoc_code thy s T) then None else
let
val Some (_, _, constrs) = assoc (descr, index);
val gr1 =
if exists (equal tname o fst) (get_assoc_types thy) then gr
else add_dt_defs thy dep (gr, descr);
in
(case assoc (constrs, s) of
None => if s mem rec_names then
mk_recfun thy gr1 dep brack s T ts rec_rewrites
else Some (pretty_case thy gr1 dep brack constrs c ts)
| Some args => Some (pretty_constr thy gr1 dep brack args c ts))
end)
| _ => None);
(**** generate code for primrec and recdef ****)
fun recfun_codegen thy gr dep brack t = (case strip_comb t of
(Const (s, T), ts) =>
(case PrimrecPackage.get_primrec thy s of
Some ps => (case find_first (fn (_, thm::_) =>
is_instance thy T (snd (dest_Const (head_of
(fst (HOLogic.dest_eq
(HOLogic.dest_Trueprop (#prop (rep_thm thm))))))))) ps of
Some (_, thms) => mk_recfun thy gr dep brack s T ts thms
| None => None)
| None => case RecdefPackage.get_recdef thy s of
Some {simps, ...} => mk_recfun thy gr dep brack s T ts simps
| None => None)
| _ => None);
val setup = [add_codegen "datatype" datatype_codegen,
add_codegen "primrec+recdef" recfun_codegen];
end;