(* Title: HOL/Tools/recfun_codegen.ML ID: $Id: recfun_codegen.ML,v 1.43 2007/11/11 13:00:08 wenzelm Exp $ Author: Stefan Berghofer, TU Muenchen Code generator for recursive functions. *) signature RECFUN_CODEGEN = sig val add: string option -> attribute val add_default: attribute val del: attribute val setup: theory -> theory end; structure RecfunCodegen : RECFUN_CODEGEN = struct open Codegen; structure RecCodegenData = TheoryDataFun ( type T = (thm * string option) list Symtab.table; val empty = Symtab.empty; val copy = I; val extend = I; fun merge _ = Symtab.merge_list (Thm.eq_thm_prop o pairself fst); ); val dest_eqn = HOLogic.dest_eq o HOLogic.dest_Trueprop; val lhs_of = fst o dest_eqn o prop_of; val const_of = dest_Const o head_of o fst o dest_eqn; fun warn thm = warning ("RecfunCodegen: Not a proper equation:\n" ^ string_of_thm thm); fun add_thm opt_module thm = if Pattern.pattern (lhs_of thm) then RecCodegenData.map (Symtab.cons_list ((fst o const_of o prop_of) thm, (thm, opt_module))) else tap (fn _ => warn thm) handle TERM _ => tap (fn _ => warn thm); fun add opt_module = Thm.declaration_attribute (fn thm => Context.mapping (add_thm opt_module thm #> Code.add_liberal_func thm) I); val add_default = Thm.declaration_attribute (fn thm => Context.mapping (add_thm NONE thm #> Code.add_default_func thm) I); fun del_thm thm = case try const_of (prop_of thm) of SOME (s, _) => RecCodegenData.map (Symtab.map_entry s (remove (Thm.eq_thm o apsnd fst) thm)) | NONE => tap (fn _ => warn thm); val del = Thm.declaration_attribute (fn thm => Context.mapping (del_thm thm #> Code.del_func thm) I) fun del_redundant thy eqs [] = eqs | del_redundant thy eqs (eq :: eqs') = let val matches = curry (Pattern.matches thy o pairself (lhs_of o fst)) in del_redundant thy (eq :: eqs) (filter_out (matches eq) eqs') end; fun get_equations thy defs (s, T) = (case Symtab.lookup (RecCodegenData.get thy) s of NONE => ([], "") | SOME thms => let val thms' = del_redundant thy [] (filter (fn (thm, _) => is_instance T (snd (const_of (prop_of thm)))) thms) in if null thms' then ([], "") else (preprocess thy (map fst thms'), case snd (snd (split_last thms')) of NONE => (case get_defn thy defs s T of NONE => thyname_of_const s thy | SOME ((_, (thyname, _)), _) => thyname) | SOME thyname => thyname) end); fun mk_suffix thy defs (s, T) = (case get_defn thy defs s T of SOME (_, SOME i) => " def" ^ string_of_int i | _ => ""); exception EQN of string * typ * string; fun cycle g (xs, x : string) = if member (op =) xs x then xs else Library.foldl (cycle g) (x :: xs, flat (Graph.all_paths (fst g) (x, x))); fun add_rec_funs thy defs gr dep eqs module = let fun dest_eq t = (fst (const_of t) ^ mk_suffix thy defs (const_of t), dest_eqn (rename_term t)); val eqs' = map dest_eq eqs; val (dname, _) :: _ = eqs'; val (s, T) = const_of (hd eqs); fun mk_fundef module fname prfx gr [] = (gr, []) | mk_fundef module fname prfx gr ((fname' : string, (lhs, rhs)) :: xs) = let val (gr1, pl) = invoke_codegen thy defs dname module false (gr, lhs); val (gr2, pr) = invoke_codegen thy defs dname module false (gr1, rhs); val (gr3, rest) = mk_fundef module 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; fun put_code module fundef = map_node dname (K (SOME (EQN ("", dummyT, dname)), module, Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk fundef @ [Pretty.str ";"])) ^ "\n\n")); in (case try (get_node gr) dname of NONE => let val gr1 = add_edge (dname, dep) (new_node (dname, (SOME (EQN (s, T, "")), module, "")) gr); val (gr2, fundef) = mk_fundef module "" "fun " gr1 eqs'; val xs = cycle gr2 ([], dname); val cs = map (fn x => case get_node gr2 x of (SOME (EQN (s, T, _)), _, _) => (s, T) | _ => error ("RecfunCodegen: illegal cyclic dependencies:\n" ^ implode (separate ", " xs))) xs in (case xs of [_] => (put_code module fundef gr2, module) | _ => if not (dep mem xs) then let val thmss as (_, thyname) :: _ = map (get_equations thy defs) cs; val module' = if_library thyname module; val eqs'' = map (dest_eq o prop_of) (List.concat (map fst thmss)); val (gr3, fundef') = mk_fundef module' "" "fun " (add_edge (dname, dep) (foldr (uncurry new_node) (del_nodes xs gr2) (map (fn k => (k, (SOME (EQN ("", dummyT, dname)), module', ""))) xs))) eqs'' in (put_code module' fundef' gr3, module') end else (gr2, module)) end | SOME (SOME (EQN (_, _, s)), module', _) => (if s = "" then if dname = dep then gr else add_edge (dname, dep) gr else if s = dep then gr else add_edge (s, dep) gr, module')) end; fun recfun_codegen thy defs gr dep module brack t = (case strip_comb t of (Const (p as (s, T)), ts) => (case (get_equations thy defs p, get_assoc_code thy (s, T)) of (([], _), _) => NONE | (_, SOME _) => NONE | ((eqns, thyname), NONE) => let val module' = if_library thyname module; val (gr', ps) = foldl_map (invoke_codegen thy defs dep module true) (gr, ts); val suffix = mk_suffix thy defs p; val (gr'', module'') = add_rec_funs thy defs gr' dep (map prop_of eqns) module'; val (gr''', fname) = mk_const_id module'' (s ^ suffix) gr'' in SOME (gr''', mk_app brack (Pretty.str (mk_qual_id module fname)) ps) end) | _ => NONE); val setup = add_codegen "recfun" recfun_codegen #> Code.add_attribute ("", Args.del |-- Scan.succeed del || Scan.option (Args.$$$ "target" |-- Args.colon |-- Args.name) >> add); end;