--- a/src/HOL/Tools/primrec_package.ML Thu Dec 06 12:58:01 2007 +0100
+++ b/src/HOL/Tools/primrec_package.ML Thu Dec 06 15:10:09 2007 +0100
@@ -1,27 +1,15 @@
(* Title: HOL/Tools/primrec_package.ML
ID: $Id$
- Author: Stefan Berghofer, TU Muenchen and Norbert Voelker, FernUni Hagen
+ Author: Stefan Berghofer, TU Muenchen; Norbert Voelker, FernUni Hagen;
+ Florian Haftmann, TU Muenchen
Package for defining functions on datatypes by primitive recursion.
*)
signature PRIMREC_PACKAGE =
sig
- val quiet_mode: bool ref
- val unify_consts: theory -> term list -> term list -> term list * term list
- val add_primrec: string -> ((bstring * string) * Attrib.src list) list
- -> theory -> thm list * theory
- val add_primrec_unchecked: string -> ((bstring * string) * Attrib.src list) list
- -> theory -> thm list * theory
- val add_primrec_i: string -> ((bstring * term) * attribute list) list
- -> theory -> thm list * theory
- val add_primrec_unchecked_i: string -> ((bstring * term) * attribute list) list
- -> theory -> thm list * theory
- (* FIXME !? *)
- val gen_primrec: ((bstring * attribute list) * thm list -> theory -> (bstring * thm list) * theory)
- -> ((bstring * attribute list) * term -> theory -> (bstring * thm) * theory)
- -> string -> ((bstring * attribute list) * term) list
- -> theory -> thm list * theory;
+ val add_primrec: (string * typ option * mixfix) list ->
+ ((bstring * Attrib.src list) * term) list -> local_theory -> thm list * local_theory
end;
structure PrimrecPackage : PRIMREC_PACKAGE =
@@ -29,98 +17,71 @@
open DatatypeAux;
-exception RecError of string;
-
-fun primrec_err s = error ("Primrec definition error:\n" ^ s);
-fun primrec_eq_err thy s eq =
- primrec_err (s ^ "\nin\n" ^ quote (Sign.string_of_term thy eq));
-
-
-(* messages *)
-
-val quiet_mode = ref false;
-fun message s = if ! quiet_mode then () else writeln s;
-
+exception PrimrecError of string * term option;
-(*the following code ensures that each recursive set always has the
- same type in all introduction rules*)
-fun unify_consts thy cs intr_ts =
- (let
- val add_term_consts_2 = fold_aterms (fn Const c => insert (op =) c | _ => I);
- fun varify (t, (i, ts)) =
- let val t' = map_types (Logic.incr_tvar (i + 1)) (snd (Type.varify [] t))
- in (maxidx_of_term t', t'::ts) end;
- val (i, cs') = foldr varify (~1, []) cs;
- val (i', intr_ts') = foldr varify (i, []) intr_ts;
- val rec_consts = fold add_term_consts_2 cs' [];
- val intr_consts = fold add_term_consts_2 intr_ts' [];
- fun unify (cname, cT) =
- let val consts = map snd (filter (fn (c, _) => c = cname) intr_consts)
- in fold (Sign.typ_unify thy) ((replicate (length consts) cT) ~~ consts) end;
- val (env, _) = fold unify rec_consts (Vartab.empty, i');
- val subst = Type.freeze o map_types (Envir.norm_type env)
+fun primrec_error msg = raise PrimrecError (msg, NONE);
+fun primrec_error_eqn msg eqn = raise PrimrecError (msg, SOME eqn);
- in (map subst cs', map subst intr_ts')
- end) handle Type.TUNIFY =>
- (warning "Occurrences of recursive constant have non-unifiable types"; (cs, intr_ts));
+fun message s = if ! Toplevel.debug then () else writeln s;
(* preprocessing of equations *)
-fun process_eqn thy eq rec_fns =
+fun process_eqn is_fixed is_const spec rec_fns =
let
- val (lhs, rhs) =
- if null (term_vars eq) then
- HOLogic.dest_eq (HOLogic.dest_Trueprop eq)
- handle TERM _ => raise RecError "not a proper equation"
- else raise RecError "illegal schematic variable(s)";
-
+ val vars = strip_qnt_vars "all" spec;
+ val body = strip_qnt_body "all" spec;
+ val eqn = curry subst_bounds (map Free (rev vars)) body;
+ val (lhs, rhs) = HOLogic.dest_eq (HOLogic.dest_Trueprop eqn)
+ handle TERM _ => primrec_error "not a proper equation";
val (recfun, args) = strip_comb lhs;
- val fnameT = dest_Const recfun handle TERM _ =>
- raise RecError "function is not declared as constant in theory";
+ val fname = case recfun of Free (v, _) => if is_fixed v then v
+ else primrec_error "illegal head of function equation"
+ | _ => primrec_error "illegal head of function equation";
val (ls', rest) = take_prefix is_Free args;
val (middle, rs') = take_suffix is_Free rest;
val rpos = length ls';
- val (constr, cargs') = if null middle then raise RecError "constructor missing"
+ val (constr, cargs') = if null middle then primrec_error "constructor missing"
else strip_comb (hd middle);
val (cname, T) = dest_Const constr
- handle TERM _ => raise RecError "ill-formed constructor";
+ handle TERM _ => primrec_error "ill-formed constructor";
val (tname, _) = dest_Type (body_type T) handle TYPE _ =>
- raise RecError "cannot determine datatype associated with function"
+ primrec_error "cannot determine datatype associated with function"
val (ls, cargs, rs) =
(map dest_Free ls', map dest_Free cargs', map dest_Free rs')
- handle TERM _ => raise RecError "illegal argument in pattern";
+ handle TERM _ => primrec_error "illegal argument in pattern";
val lfrees = ls @ rs @ cargs;
fun check_vars _ [] = ()
- | check_vars s vars = raise RecError (s ^ commas_quote (map fst vars))
+ | check_vars s vars = primrec_error (s ^ commas_quote (map fst vars)) eqn;
in
if length middle > 1 then
- raise RecError "more than one non-variable in pattern"
+ primrec_error "more than one non-variable in pattern"
else
(check_vars "repeated variable names in pattern: " (duplicates (op =) lfrees);
check_vars "extra variables on rhs: "
- (map dest_Free (term_frees rhs) \\ lfrees);
- case AList.lookup (op =) rec_fns fnameT of
+ (map dest_Free (term_frees rhs) |> subtract (op =) lfrees
+ |> filter_out (is_const o fst) |> filter_out (is_fixed o fst));
+ case AList.lookup (op =) rec_fns fname of
NONE =>
- (fnameT, (tname, rpos, [(cname, (ls, cargs, rs, rhs, eq))]))::rec_fns
+ (fname, (tname, rpos, [(cname, (ls, cargs, rs, rhs, eqn))]))::rec_fns
| SOME (_, rpos', eqns) =>
if AList.defined (op =) eqns cname then
- raise RecError "constructor already occurred as pattern"
+ primrec_error "constructor already occurred as pattern"
else if rpos <> rpos' then
- raise RecError "position of recursive argument inconsistent"
+ primrec_error "position of recursive argument inconsistent"
else
- AList.update (op =) (fnameT, (tname, rpos, (cname, (ls, cargs, rs, rhs, eq))::eqns))
+ AList.update (op =)
+ (fname, (tname, rpos, (cname, (ls, cargs, rs, rhs, eqn))::eqns))
rec_fns)
- end
- handle RecError s => primrec_eq_err thy s eq;
+ end handle PrimrecError (msg, NONE) => primrec_error_eqn msg spec;
-fun process_fun thy descr rec_eqns (i, fnameT as (fname, _)) (fnameTs, fnss) =
+fun process_fun descr eqns (i, fname) (fnames, fnss) =
let
- val (_, (tname, _, constrs)) = List.nth (descr, i);
+ val (_, (tname, _, constrs)) = nth descr i;
(* substitute "fname ls x rs" by "y ls rs" for (x, (_, y)) in subs *)
@@ -133,14 +94,13 @@
let
val (f, ts) = strip_comb t;
in
- if is_Const f andalso dest_Const f mem map fst rec_eqns then
+ if is_Free f
+ andalso member (fn ((v, _), (w, _)) => v = w) eqns (dest_Free f) then
let
- val fnameT' as (fname', _) = dest_Const f;
- val (_, rpos, _) = the (AList.lookup (op =) rec_eqns fnameT');
- val ls = Library.take (rpos, ts);
- val rest = Library.drop (rpos, ts);
- val (x', rs) = (hd rest, tl rest)
- handle Empty => raise RecError ("not enough arguments\
+ val (fname', _) = dest_Free f;
+ val (_, rpos, _) = the (AList.lookup (op =) eqns fname');
+ val (ls, x' :: rs) = chop rpos ts
+ handle Empty => primrec_error ("not enough arguments\
\ in recursive application\nof function " ^ quote fname' ^ " on rhs");
val (x, xs) = strip_comb x'
in case AList.lookup (op =) subs x
@@ -151,7 +111,7 @@
| SOME (i', y) =>
fs
|> fold_map (subst subs) (xs @ ls @ rs)
- ||> process_fun thy descr rec_eqns (i', fnameT')
+ ||> process_fun descr eqns (i', fname')
|-> (fn ts' => pair (list_comb (y, ts')))
end
else
@@ -163,41 +123,39 @@
(* translate rec equations into function arguments suitable for rec comb *)
- fun trans eqns (cname, cargs) (fnameTs', fnss', fns) =
+ fun trans eqns (cname, cargs) (fnames', fnss', fns) =
(case AList.lookup (op =) eqns cname of
NONE => (warning ("No equation for constructor " ^ quote cname ^
"\nin definition of function " ^ quote fname);
- (fnameTs', fnss', (Const ("HOL.undefined", dummyT))::fns))
+ (fnames', fnss', (Const ("HOL.undefined", dummyT))::fns))
| SOME (ls, cargs', rs, rhs, eq) =>
let
val recs = filter (is_rec_type o snd) (cargs' ~~ cargs);
val rargs = map fst recs;
val subs = map (rpair dummyT o fst)
(rev (rename_wrt_term rhs rargs));
- val (rhs', (fnameTs'', fnss'')) =
- (subst (map (fn ((x, y), z) =>
- (Free x, (body_index y, Free z)))
- (recs ~~ subs)) rhs (fnameTs', fnss'))
- handle RecError s => primrec_eq_err thy s eq
- in (fnameTs'', fnss'',
+ val (rhs', (fnames'', fnss'')) = (subst (map2 (fn (x, y) => fn z =>
+ (Free x, (body_index y, Free z))) recs subs) rhs (fnames', fnss'))
+ handle PrimrecError (s, NONE) => primrec_error_eqn s eq
+ in (fnames'', fnss'',
(list_abs_free (cargs' @ subs @ ls @ rs, rhs'))::fns)
end)
- in (case AList.lookup (op =) fnameTs i of
+ in (case AList.lookup (op =) fnames i of
NONE =>
- if exists (equal fnameT o snd) fnameTs then
- raise RecError ("inconsistent functions for datatype " ^ quote tname)
+ if exists (fn (_, v) => fname = v) fnames then
+ primrec_error ("inconsistent functions for datatype " ^ quote tname)
else
let
- val (_, _, eqns) = the (AList.lookup (op =) rec_eqns fnameT);
- val (fnameTs', fnss', fns) = fold_rev (trans eqns) constrs
- ((i, fnameT)::fnameTs, fnss, [])
+ val (_, _, eqns) = the (AList.lookup (op =) eqns fname);
+ val (fnames', fnss', fns) = fold_rev (trans eqns) constrs
+ ((i, fname)::fnames, fnss, [])
in
- (fnameTs', (i, (fname, #1 (snd (hd eqns)), fns))::fnss')
+ (fnames', (i, (fname, #1 (snd (hd eqns)), fns))::fnss')
end
- | SOME fnameT' =>
- if fnameT = fnameT' then (fnameTs, fnss)
- else raise RecError ("inconsistent functions for datatype " ^ quote tname))
+ | SOME fname' =>
+ if fname = fname' then (fnames, fnss)
+ else primrec_error ("inconsistent functions for datatype " ^ quote tname))
end;
@@ -219,17 +177,17 @@
(* make definition *)
-fun make_def thy fs (fname, ls, rec_name, tname) =
+fun make_def ctxt fixes fs (fname, ls, rec_name, tname) =
let
- val rhs = fold_rev (fn T => fn t => Abs ("", T, t))
+ val raw_rhs = fold_rev (fn T => fn t => Abs ("", T, t))
((map snd ls) @ [dummyT])
(list_comb (Const (rec_name, dummyT),
fs @ map Bound (0 ::(length ls downto 1))))
- val def_name = Sign.base_name fname ^ "_" ^ Sign.base_name tname ^ "_def";
- val def_prop =
- singleton (Syntax.check_terms (ProofContext.init thy))
- (Logic.mk_equals (Const (fname, dummyT), rhs));
- in (def_name, def_prop) end;
+ val def_name = Thm.def_name (Sign.base_name fname);
+ val rhs = singleton (Syntax.check_terms ctxt) raw_rhs;
+ val SOME mfx = get_first
+ (fn ((v, _), mfx) => if v = fname then SOME mfx else NONE) fixes;
+ in ((fname, mfx), ((def_name, []), rhs)) end;
(* find datatypes which contain all datatypes in tnames' *)
@@ -237,103 +195,87 @@
fun find_dts (dt_info : datatype_info Symtab.table) _ [] = []
| find_dts dt_info tnames' (tname::tnames) =
(case Symtab.lookup dt_info tname of
- NONE => primrec_err (quote tname ^ " is not a datatype")
+ NONE => primrec_error (quote tname ^ " is not a datatype")
| SOME dt =>
if tnames' subset (map (#1 o snd) (#descr dt)) then
(tname, dt)::(find_dts dt_info tnames' tnames)
else find_dts dt_info tnames' tnames);
-fun prepare_induct ({descr, induction, ...}: datatype_info) rec_eqns =
+
+(* adapted induction rule *)
+
+fun prepare_induct ({descr, induction, ...}: datatype_info) eqns =
let
fun constrs_of (_, (_, _, cs)) =
map (fn (cname:string, (_, cargs, _, _, _)) => (cname, map fst cargs)) cs;
- val params_of = these o AList.lookup (op =) (List.concat (map constrs_of rec_eqns));
+ val params_of = these o AList.lookup (op =) (List.concat (map constrs_of eqns));
in
induction
- |> RuleCases.rename_params (map params_of (List.concat (map (map #1 o #3 o #2) descr)))
+ |> RuleCases.rename_params (map params_of (maps (map #1 o #3 o #2) descr))
|> RuleCases.save induction
end;
+
+(* primrec definition *)
+
local
-fun gen_primrec_i note def alt_name eqns_atts thy =
+fun prepare_spec prep_spec ctxt raw_fixes raw_spec =
+ let
+ val ((fixes, spec), _) = prep_spec raw_fixes [(map o apsnd) single raw_spec] ctxt
+ in (fixes, (map o apsnd) the_single spec) end;
+
+fun prove_spec ctxt rec_rewrites defs =
+ let
+ val rewrites = map mk_meta_eq rec_rewrites @ map (snd o snd) defs;
+ fun tac _ = EVERY [rewrite_goals_tac rewrites, rtac refl 1];
+ val _ = message "Proving equations for primrec function";
+ in map (fn (name_attr, t) => (name_attr, [Goal.prove ctxt [] [] t tac])) end;
+
+fun gen_primrec prep_spec raw_fixes raw_spec lthy =
let
- val (eqns, atts) = split_list eqns_atts;
- val dt_info = DatatypePackage.get_datatypes thy;
- val rec_eqns = fold_rev (process_eqn thy o snd) eqns [] ;
- val tnames = distinct (op =) (map (#1 o snd) rec_eqns);
- val dts = find_dts dt_info tnames tnames;
- val main_fns =
- map (fn (tname, {index, ...}) =>
- (index,
- (fst o the o find_first (fn f => (#1 o snd) f = tname)) rec_eqns))
- dts;
+ val (fixes, spec) = prepare_spec prep_spec lthy raw_fixes raw_spec;
+ val eqns = fold_rev (process_eqn (member (op =) (map (fst o fst) fixes))
+ (Variable.is_const lthy) o snd) spec [];
+ val tnames = distinct (op =) (map (#1 o snd) eqns);
+ val dts = find_dts (DatatypePackage.get_datatypes
+ (ProofContext.theory_of lthy)) tnames tnames;
+ val main_fns = map (fn (tname, {index, ...}) =>
+ (index, (fst o the o find_first (fn (_, x) => #1 x = tname)) eqns)) dts;
val {descr, rec_names, rec_rewrites, ...} =
- if null dts then
- primrec_err ("datatypes " ^ commas_quote tnames ^ "\nare not mutually recursive")
+ if null dts then primrec_error
+ ("datatypes " ^ commas_quote tnames ^ "\nare not mutually recursive")
else snd (hd dts);
- val (fnameTs, fnss) =
- fold_rev (process_fun thy descr rec_eqns) main_fns ([], []);
+ val (fnames, fnss) = fold_rev (process_fun descr eqns) main_fns ([], []);
val (fs, defs) = fold_rev (get_fns fnss) (descr ~~ rec_names) ([], []);
- val defs' = map (make_def thy fs) defs;
- val nameTs1 = map snd fnameTs;
- val nameTs2 = map fst rec_eqns;
+ val nameTs1 = map snd fnames;
+ val nameTs2 = map fst eqns;
val _ = if gen_eq_set (op =) (nameTs1, nameTs2) then ()
- else primrec_err ("functions " ^ commas_quote (map fst nameTs2) ^
- "\nare not mutually recursive");
- val primrec_name =
- if alt_name = "" then (space_implode "_" (map (Sign.base_name o #1) defs)) else alt_name;
- val (defs_thms', thy') =
- thy
- |> Sign.add_path primrec_name
- |> fold_map def (map (fn (name, t) => ((name, []), t)) defs');
- val rewrites = (map mk_meta_eq rec_rewrites) @ map snd defs_thms';
- val _ = message ("Proving equations for primrec function(s) " ^
- commas_quote (map fst nameTs1) ^ " ...");
- val simps = map (fn (_, t) => Goal.prove_global thy' [] [] t
- (fn _ => EVERY [rewrite_goals_tac rewrites, rtac refl 1])) eqns;
- val (simps', thy'') =
- thy'
- |> fold_map note ((map fst eqns ~~ atts) ~~ map single simps);
- val simps'' = maps snd simps';
+ else primrec_error ("functions " ^ commas_quote nameTs2 ^
+ "\nare not mutually recursive");
+ val qualify = NameSpace.qualified
+ (space_implode "_" (map (Sign.base_name o #1) defs));
+ val simp_atts = [Attrib.internal (K Simplifier.simp_add),
+ Code.add_default_func_attr (*FIXME*)];
in
- thy''
- |> note (("simps", [Simplifier.simp_add, RecfunCodegen.add_default]), simps'')
- |> snd
- |> note (("induct", []), [prepare_induct (#2 (hd dts)) rec_eqns])
- |> snd
- |> Sign.parent_path
- |> pair simps''
- end;
-
-fun gen_primrec note def alt_name eqns thy =
- let
- val ((names, strings), srcss) = apfst split_list (split_list eqns);
- val atts = map (map (Attrib.attribute thy)) srcss;
- val eqn_ts = map (fn s => Syntax.read_prop_global thy s
- handle ERROR msg => cat_error msg ("The error(s) above occurred for " ^ s)) strings;
- val rec_ts = map (fn eq => head_of (fst (HOLogic.dest_eq (HOLogic.dest_Trueprop eq)))
- handle TERM _ => primrec_eq_err thy "not a proper equation" eq) eqn_ts;
- val (_, eqn_ts') = unify_consts thy rec_ts eqn_ts
- in
- gen_primrec_i note def alt_name (names ~~ eqn_ts' ~~ atts) thy
- end;
-
-fun thy_note ((name, atts), thms) =
- PureThy.add_thmss [((name, thms), atts)] #-> (fn [thms] => pair (name, thms));
-fun thy_def false ((name, atts), t) =
- PureThy.add_defs_i false [((name, t), atts)] #-> (fn [thm] => pair (name, thm))
- | thy_def true ((name, atts), t) =
- PureThy.add_defs_unchecked_i false [((name, t), atts)] #-> (fn [thm] => pair (name, thm));
+ lthy
+ |> fold_map (LocalTheory.define Thm.definitionK o make_def lthy fixes fs) defs
+ |-> (fn defs => `(fn ctxt => prove_spec ctxt rec_rewrites defs spec))
+ |-> (fn simps => fold_map (LocalTheory.note Thm.theoremK) simps)
+ |-> (fn simps' => LocalTheory.note Thm.theoremK
+ ((qualify "simps", simp_atts), maps snd simps'))
+ ||>> LocalTheory.note Thm.theoremK
+ ((qualify "induct", []), [prepare_induct (#2 (hd dts)) eqns])
+ |>> (snd o fst)
+ end handle PrimrecError (msg, some_eqn) =>
+ error ("Primrec definition error:\n" ^ msg ^ (case some_eqn
+ of SOME eqn => "\nin\n" ^ quote (Syntax.string_of_term lthy eqn)
+ | NONE => ""));
in
-val add_primrec = gen_primrec thy_note (thy_def false);
-val add_primrec_unchecked = gen_primrec thy_note (thy_def true);
-val add_primrec_i = gen_primrec_i thy_note (thy_def false);
-val add_primrec_unchecked_i = gen_primrec_i thy_note (thy_def true);
-fun gen_primrec note def alt_name specs =
- gen_primrec_i note def alt_name (map (fn ((name, t), atts) => ((name, atts), t)) specs);
+val add_primrec = gen_primrec Specification.check_specification;
+val add_primrec_cmd = gen_primrec Specification.read_specification;
end;
@@ -347,15 +289,27 @@
(((P.$$$ "unchecked" >> K true) -- Scan.optional P.name "" ||
P.name >> pair false) --| P.$$$ ")")) (false, "");
-val primrec_decl =
+val old_primrec_decl =
opt_unchecked_name -- Scan.repeat1 (SpecParse.opt_thm_name ":" -- P.prop);
+fun pipe_error t = P.!!! (Scan.fail_with (K
+ (cat_lines ["Equations must be separated by " ^ quote "|", quote t])));
+
+val statement = SpecParse.opt_thm_name ":" -- P.prop --| Scan.ahead
+ ((P.term :-- pipe_error) || Scan.succeed ("",""));
+
+val statements = P.enum1 "|" statement;
+
+val primrec_decl = P.opt_target -- P.fixes --| P.$$$ "where" -- statements;
+
val _ =
OuterSyntax.command "primrec" "define primitive recursive functions on datatypes" K.thy_decl
- (primrec_decl >> (fn ((unchecked, alt_name), eqns) =>
+ ((primrec_decl >> (fn ((opt_target, raw_fixes), raw_spec) =>
+ Toplevel.local_theory opt_target (add_primrec_cmd raw_fixes raw_spec #> snd)))
+ || (old_primrec_decl >> (fn ((unchecked, alt_name), eqns) =>
Toplevel.theory (snd o
- (if unchecked then add_primrec_unchecked else add_primrec) alt_name
- (map P.triple_swap eqns))));
+ (if unchecked then OldPrimrecPackage.add_primrec_unchecked else OldPrimrecPackage.add_primrec) alt_name
+ (map P.triple_swap eqns)))));
end;