(* Title: Tools/nbe.ML
Authors: Klaus Aehlig, LMU Muenchen; Tobias Nipkow, Florian Haftmann, TU Muenchen
Normalization by evaluation, based on generic code generator.
*)
signature NBE =
sig
val norm_conv: cterm -> thm
val norm: theory -> term -> term
datatype Univ =
Const of int * Univ list (*named (uninterpreted) constants*)
| DFree of string * int (*free (uninterpreted) dictionary parameters*)
| BVar of int * Univ list
| Abs of (int * (Univ list -> Univ)) * Univ list
val apps: Univ -> Univ list -> Univ (*explicit applications*)
val abss: int -> (Univ list -> Univ) -> Univ
(*abstractions as closures*)
val same: Univ -> Univ -> bool
val univs_ref: (unit -> Univ list -> Univ list) option Unsynchronized.ref
val trace: bool Unsynchronized.ref
val setup: theory -> theory
val add_const_alias: thm -> theory -> theory
end;
structure Nbe: NBE =
struct
(* generic non-sense *)
val trace = Unsynchronized.ref false;
fun traced f x = if !trace then (tracing (f x); x) else x;
(** certificates and oracle for "trivial type classes" **)
structure Triv_Class_Data = Theory_Data
(
type T = (class * thm) list;
val empty = [];
val extend = I;
fun merge data : T = AList.merge (op =) (K true) data;
);
fun add_const_alias thm thy =
let
val (ofclass, eqn) = case try Logic.dest_equals (Thm.prop_of thm)
of SOME ofclass_eq => ofclass_eq
| _ => error ("Bad certificate: " ^ Display.string_of_thm_global thy thm);
val (T, class) = case try Logic.dest_of_class ofclass
of SOME T_class => T_class
| _ => error ("Bad certificate: " ^ Display.string_of_thm_global thy thm);
val tvar = case try Term.dest_TVar T
of SOME (tvar as (_, sort)) => if null (filter (can (AxClass.get_info thy)) sort)
then tvar
else error ("Bad sort: " ^ Display.string_of_thm_global thy thm)
| _ => error ("Bad type: " ^ Display.string_of_thm_global thy thm);
val _ = if Term.add_tvars eqn [] = [tvar] then ()
else error ("Inconsistent type: " ^ Display.string_of_thm_global thy thm);
val lhs_rhs = case try Logic.dest_equals eqn
of SOME lhs_rhs => lhs_rhs
| _ => error ("Not an equation: " ^ Syntax.string_of_term_global thy eqn);
val c_c' = case try (pairself (Code.check_const thy)) lhs_rhs
of SOME c_c' => c_c'
| _ => error ("Not an equation with two constants: "
^ Syntax.string_of_term_global thy eqn);
val _ = if the_list (AxClass.class_of_param thy (snd c_c')) = [class] then ()
else error ("Inconsistent class: " ^ Display.string_of_thm_global thy thm);
in Triv_Class_Data.map (AList.update (op =) (class, thm)) thy end;
local
val get_triv_classes = map fst o Triv_Class_Data.get;
val (_, triv_of_class) = Context.>>> (Context.map_theory_result
(Thm.add_oracle (Binding.name "triv_of_class", fn (thy, T, class) =>
Thm.cterm_of thy (Logic.mk_of_class (T, class)))));
in
fun lift_triv_classes_conv thy conv ct =
let
val algebra = Sign.classes_of thy;
val certT = Thm.ctyp_of thy;
val triv_classes = get_triv_classes thy;
fun additional_classes sort = filter_out (fn class => Sorts.sort_le algebra (sort, [class])) triv_classes;
fun mk_entry (v, sort) =
let
val T = TFree (v, sort);
val cT = certT T;
val triv_sort = additional_classes sort;
in
(v, (Sorts.inter_sort algebra (sort, triv_sort),
(cT, AList.make (fn class => Thm.of_class (cT, class)) sort
@ AList.make (fn class => triv_of_class (thy, T, class)) triv_sort)))
end;
val vs_tab = map mk_entry (Term.add_tfrees (Thm.term_of ct) []);
fun instantiate thm =
let
val cert_tvars = map (certT o TVar) (Term.add_tvars
((fst o Logic.dest_equals o Logic.strip_imp_concl o Thm.prop_of) thm) []);
val instantiation =
map2 (fn cert_tvar => fn (_, (_, (cT, _))) => (cert_tvar, cT)) cert_tvars vs_tab;
in Thm.instantiate (instantiation, []) thm end;
fun of_class (TFree (v, _), class) =
the (AList.lookup (op =) ((snd o snd o the o AList.lookup (op =) vs_tab) v) class)
| of_class (T, _) = error ("Bad type " ^ Syntax.string_of_typ_global thy T);
fun strip_of_class thm =
let
val prems_of_class = Thm.prop_of thm
|> Logic.strip_imp_prems
|> map (Logic.dest_of_class #> of_class);
in fold Thm.elim_implies prems_of_class thm end;
in
ct
|> (Drule.cterm_fun o map_types o map_type_tfree)
(fn (v, sort) => TFree (v, (fst o the o AList.lookup (op =) vs_tab) v))
|> conv
|> Thm.strip_shyps
|> Thm.varifyT_global
|> Thm.unconstrainT
|> instantiate
|> strip_of_class
end;
fun lift_triv_classes_rew thy rew t =
let
val algebra = Sign.classes_of thy;
val triv_classes = get_triv_classes thy;
val vs = Term.add_tfrees t [];
in t
|> (map_types o map_type_tfree)
(fn (v, sort) => TFree (v, Sorts.inter_sort algebra (sort, triv_classes)))
|> rew
|> (map_types o map_type_tfree)
(fn (v, _) => TFree (v, the (AList.lookup (op =) vs v)))
end;
end;
(** the semantic universe **)
(*
Functions are given by their semantical function value. To avoid
trouble with the ML-type system, these functions have the most
generic type, that is "Univ list -> Univ". The calling convention is
that the arguments come as a list, the last argument first. In
other words, a function call that usually would look like
f x_1 x_2 ... x_n or f(x_1,x_2, ..., x_n)
would be in our convention called as
f [x_n,..,x_2,x_1]
Moreover, to handle functions that are still waiting for some
arguments we have additionally a list of arguments collected to far
and the number of arguments we're still waiting for.
*)
datatype Univ =
Const of int * Univ list (*named (uninterpreted) constants*)
| DFree of string * int (*free (uninterpreted) dictionary parameters*)
| BVar of int * Univ list (*bound variables, named*)
| Abs of (int * (Univ list -> Univ)) * Univ list
(*abstractions as closures*);
fun same (Const (k, xs)) (Const (l, ys)) = k = l andalso sames xs ys
| same (DFree (s, k)) (DFree (t, l)) = s = t andalso k = l
| same (BVar (k, xs)) (BVar (l, ys)) = k = l andalso sames xs ys
| same _ _ = false
and sames xs ys = length xs = length ys andalso forall (uncurry same) (xs ~~ ys);
(* constructor functions *)
fun abss n f = Abs ((n, f), []);
fun apps (Abs ((n, f), xs)) ys = let val k = n - length ys in
case int_ord (k, 0)
of EQUAL => f (ys @ xs)
| LESS => let val (zs, ws) = chop (~ k) ys in apps (f (ws @ xs)) zs end
| GREATER => Abs ((k, f), ys @ xs) (*note: reverse convention also for apps!*)
end
| apps (Const (name, xs)) ys = Const (name, ys @ xs)
| apps (BVar (n, xs)) ys = BVar (n, ys @ xs);
(** assembling and compiling ML code from terms **)
(* abstract ML syntax *)
infix 9 `$` `$$`;
fun e1 `$` e2 = "(" ^ e1 ^ " " ^ e2 ^ ")";
fun e `$$` [] = e
| e `$$` es = "(" ^ e ^ " " ^ space_implode " " es ^ ")";
fun ml_abs v e = "(fn " ^ v ^ " => " ^ e ^ ")";
fun ml_cases t cs =
"(case " ^ t ^ " of " ^ space_implode " | " (map (fn (p, t) => p ^ " => " ^ t) cs) ^ ")";
fun ml_Let d e = "let\n" ^ d ^ " in " ^ e ^ " end";
fun ml_as v t = "(" ^ v ^ " as " ^ t ^ ")";
fun ml_and [] = "true"
| ml_and [x] = x
| ml_and xs = "(" ^ space_implode " andalso " xs ^ ")";
fun ml_if b x y = "(if " ^ b ^ " then " ^ x ^ " else " ^ y ^ ")";
fun ml_list es = "[" ^ commas es ^ "]";
fun ml_fundefs ([(name, [([], e)])]) =
"val " ^ name ^ " = " ^ e ^ "\n"
| ml_fundefs (eqs :: eqss) =
let
fun fundef (name, eqs) =
let
fun eqn (es, e) = name ^ " " ^ space_implode " " es ^ " = " ^ e
in space_implode "\n | " (map eqn eqs) end;
in
(prefix "fun " o fundef) eqs :: map (prefix "and " o fundef) eqss
|> cat_lines
|> suffix "\n"
end;
(* nbe specific syntax and sandbox communication *)
val univs_ref = Unsynchronized.ref (NONE : (unit -> Univ list -> Univ list) option);
local
val prefix = "Nbe.";
val name_ref = prefix ^ "univs_ref";
val name_const = prefix ^ "Const";
val name_abss = prefix ^ "abss";
val name_apps = prefix ^ "apps";
val name_same = prefix ^ "same";
in
val univs_cookie = (name_ref, univs_ref);
fun nbe_fun 0 "" = "nbe_value"
| nbe_fun i c = "c_" ^ translate_string (fn "." => "_" | c => c) c ^ "_" ^ string_of_int i;
fun nbe_dict v n = "d_" ^ v ^ "_" ^ string_of_int n;
fun nbe_bound v = "v_" ^ v;
fun nbe_bound_optional NONE = "_"
| nbe_bound_optional (SOME v) = nbe_bound v;
fun nbe_default v = "w_" ^ v;
(*note: these three are the "turning spots" where proper argument order is established!*)
fun nbe_apps t [] = t
| nbe_apps t ts = name_apps `$$` [t, ml_list (rev ts)];
fun nbe_apps_local i c ts = nbe_fun i c `$` ml_list (rev ts);
fun nbe_apps_constr idx_of c ts =
let
val c' = if !trace then string_of_int (idx_of c) ^ " (*" ^ c ^ "*)"
else string_of_int (idx_of c);
in name_const `$` ("(" ^ c' ^ ", " ^ ml_list (rev ts) ^ ")") end;
fun nbe_abss 0 f = f `$` ml_list []
| nbe_abss n f = name_abss `$$` [string_of_int n, f];
fun nbe_same v1 v2 = "(" ^ name_same ^ " " ^ nbe_bound v1 ^ " " ^ nbe_bound v2 ^ ")";
end;
open Basic_Code_Thingol;
(* code generation *)
fun assemble_eqnss idx_of deps eqnss =
let
fun prep_eqns (c, (vs, eqns)) =
let
val dicts = maps (fn (v, sort) => map_index (nbe_dict v o fst) sort) vs;
val num_args = length dicts + ((length o fst o hd) eqns);
in (c, (num_args, (dicts, eqns))) end;
val eqnss' = map prep_eqns eqnss;
fun assemble_constapp c dss ts =
let
val ts' = (maps o map) assemble_idict dss @ ts;
in case AList.lookup (op =) eqnss' c
of SOME (num_args, _) => if num_args <= length ts'
then let val (ts1, ts2) = chop num_args ts'
in nbe_apps (nbe_apps_local 0 c ts1) ts2
end else nbe_apps (nbe_abss num_args (nbe_fun 0 c)) ts'
| NONE => if member (op =) deps c
then nbe_apps (nbe_fun 0 c) ts'
else nbe_apps_constr idx_of c ts'
end
and assemble_idict (DictConst (inst, dss)) =
assemble_constapp inst dss []
| assemble_idict (DictVar (supers, (v, (n, _)))) =
fold_rev (fn super => assemble_constapp super [] o single) supers (nbe_dict v n);
fun assemble_iterm constapp =
let
fun of_iterm match_cont t =
let
val (t', ts) = Code_Thingol.unfold_app t
in of_iapp match_cont t' (fold_rev (cons o of_iterm NONE) ts []) end
and of_iapp match_cont (IConst (c, ((_, dss), _))) ts = constapp c dss ts
| of_iapp match_cont (IVar v) ts = nbe_apps (nbe_bound_optional v) ts
| of_iapp match_cont ((v, _) `|=> t) ts =
nbe_apps (nbe_abss 1 (ml_abs (ml_list [nbe_bound_optional v]) (of_iterm NONE t))) ts
| of_iapp match_cont (ICase (((t, _), cs), t0)) ts =
nbe_apps (ml_cases (of_iterm NONE t)
(map (fn (p, t) => (of_iterm NONE p, of_iterm match_cont t)) cs
@ [("_", case match_cont of SOME s => s | NONE => of_iterm NONE t0)])) ts
in of_iterm end;
fun subst_nonlin_vars args =
let
val vs = (fold o Code_Thingol.fold_varnames)
(fn v => AList.map_default (op =) (v, 0) (Integer.add 1)) args [];
val names = Name.make_context (map fst vs);
fun declare v k ctxt = let val vs = Name.invents ctxt v k
in (vs, fold Name.declare vs ctxt) end;
val (vs_renames, _) = fold_map (fn (v, k) => if k > 1
then declare v (k - 1) #>> (fn vs => (v, vs))
else pair (v, [])) vs names;
val samepairs = maps (fn (v, vs) => map (pair v) vs) vs_renames;
fun subst_vars (t as IConst _) samepairs = (t, samepairs)
| subst_vars (t as IVar NONE) samepairs = (t, samepairs)
| subst_vars (t as IVar (SOME v)) samepairs = (case AList.lookup (op =) samepairs v
of SOME v' => (IVar (SOME v'), AList.delete (op =) v samepairs)
| NONE => (t, samepairs))
| subst_vars (t1 `$ t2) samepairs = samepairs
|> subst_vars t1
||>> subst_vars t2
|>> (op `$)
| subst_vars (ICase (_, t)) samepairs = subst_vars t samepairs;
val (args', _) = fold_map subst_vars args samepairs;
in (samepairs, args') end;
fun assemble_eqn c dicts default_args (i, (args, rhs)) =
let
val is_eval = (c = "");
val default_rhs = nbe_apps_local (i+1) c (dicts @ default_args);
val match_cont = if is_eval then NONE else SOME default_rhs;
val assemble_arg = assemble_iterm
(fn c => fn _ => fn ts => nbe_apps_constr idx_of c ts) NONE;
val assemble_rhs = assemble_iterm assemble_constapp match_cont;
val (samepairs, args') = subst_nonlin_vars args;
val s_args = map assemble_arg args';
val s_rhs = if null samepairs then assemble_rhs rhs
else ml_if (ml_and (map (uncurry nbe_same) samepairs))
(assemble_rhs rhs) default_rhs;
val eqns = if is_eval then
[([ml_list (rev (dicts @ s_args))], s_rhs)]
else
[([ml_list (rev (dicts @ map2 ml_as default_args s_args))], s_rhs),
([ml_list (rev (dicts @ default_args))], default_rhs)]
in (nbe_fun i c, eqns) end;
fun assemble_eqns (c, (num_args, (dicts, eqns))) =
let
val default_args = map nbe_default
(Name.invent_list [] "a" (num_args - length dicts));
val eqns' = map_index (assemble_eqn c dicts default_args) eqns
@ (if c = "" then [] else [(nbe_fun (length eqns) c,
[([ml_list (rev (dicts @ default_args))],
nbe_apps_constr idx_of c (dicts @ default_args))])]);
in (eqns', nbe_abss num_args (nbe_fun 0 c)) end;
val (fun_vars, fun_vals) = map_split assemble_eqns eqnss';
val deps_vars = ml_list (map (nbe_fun 0) deps);
in ml_abs deps_vars (ml_Let (ml_fundefs (flat fun_vars)) (ml_list fun_vals)) end;
(* code compilation *)
fun compile_eqnss ctxt gr raw_deps [] = []
| compile_eqnss ctxt gr raw_deps eqnss =
let
val (deps, deps_vals) = split_list (map_filter
(fn dep => Option.map (fn univ => (dep, univ)) (fst ((Graph.get_node gr dep)))) raw_deps);
val idx_of = raw_deps
|> map (fn dep => (dep, snd (Graph.get_node gr dep)))
|> AList.lookup (op =)
|> (fn f => the o f);
val s = assemble_eqnss idx_of deps eqnss;
val cs = map fst eqnss;
in
s
|> traced (fn s => "\n--- code to be evaluated:\n" ^ s)
|> ML_Context.evaluate ctxt (!trace) univs_cookie
|> (fn f => f deps_vals)
|> (fn univs => cs ~~ univs)
end;
(* preparing function equations *)
fun eqns_of_stmt (_, Code_Thingol.Fun (_, ((_, []), _))) =
[]
| eqns_of_stmt (const, Code_Thingol.Fun (_, (((vs, _), eqns), _))) =
[(const, (vs, map fst eqns))]
| eqns_of_stmt (_, Code_Thingol.Datatypecons _) =
[]
| eqns_of_stmt (_, Code_Thingol.Datatype _) =
[]
| eqns_of_stmt (class, Code_Thingol.Class (_, (v, (super_classes, classparams)))) =
let
val names = map snd super_classes @ map fst classparams;
val params = Name.invent_list [] "d" (length names);
fun mk (k, name) =
(name, ([(v, [])],
[([IConst (class, (([], []), [])) `$$ map (IVar o SOME) params],
IVar (SOME (nth params k)))]));
in map_index mk names end
| eqns_of_stmt (_, Code_Thingol.Classrel _) =
[]
| eqns_of_stmt (_, Code_Thingol.Classparam _) =
[]
| eqns_of_stmt (inst, Code_Thingol.Classinst ((class, (_, arity_args)), (super_instances, (classparam_instances, _)))) =
[(inst, (arity_args, [([], IConst (class, (([], []), [])) `$$
map (fn (_, (_, (inst, dss))) => IConst (inst, (([], dss), []))) super_instances
@ map (IConst o snd o fst) classparam_instances)]))];
fun compile_stmts ctxt stmts_deps =
let
val names = map (fst o fst) stmts_deps;
val names_deps = map (fn ((name, _), deps) => (name, deps)) stmts_deps;
val eqnss = maps (eqns_of_stmt o fst) stmts_deps;
val refl_deps = names_deps
|> maps snd
|> distinct (op =)
|> fold (insert (op =)) names;
fun new_node name (gr, (maxidx, idx_tab)) = if can (Graph.get_node gr) name
then (gr, (maxidx, idx_tab))
else (Graph.new_node (name, (NONE, maxidx)) gr,
(maxidx + 1, Inttab.update_new (maxidx, name) idx_tab));
fun compile gr = eqnss
|> compile_eqnss ctxt gr refl_deps
|> rpair gr;
in
fold new_node refl_deps
#> apfst (fold (fn (name, deps) => fold (curry Graph.add_edge name) deps) names_deps
#> compile
#-> fold (fn (name, univ) => (Graph.map_node name o apfst) (K (SOME univ))))
end;
fun ensure_stmts ctxt program =
let
fun add_stmts names (gr, (maxidx, idx_tab)) = if exists ((can o Graph.get_node) gr) names
then (gr, (maxidx, idx_tab))
else (gr, (maxidx, idx_tab))
|> compile_stmts ctxt (map (fn name => ((name, Graph.get_node program name),
Graph.imm_succs program name)) names);
in
fold_rev add_stmts (Graph.strong_conn program)
end;
(** evaluation **)
(* term evaluation *)
fun eval_term ctxt gr deps (vs : (string * sort) list, t) =
let
val dict_frees = maps (fn (v, sort) => map_index (curry DFree v o fst) sort) vs;
in
("", (vs, [([], t)]))
|> singleton (compile_eqnss ctxt gr deps)
|> snd
|> (fn t => apps t (rev dict_frees))
end;
(* reification *)
fun typ_of_itype program vs (ityco `%% itys) =
let
val Code_Thingol.Datatype (tyco, _) = Graph.get_node program ityco;
in Type (tyco, map (typ_of_itype program vs) itys) end
| typ_of_itype program vs (ITyVar v) =
let
val sort = (the o AList.lookup (op =) vs) v;
in TFree ("'" ^ v, sort) end;
fun term_of_univ thy program idx_tab t =
let
fun take_until f [] = []
| take_until f (x::xs) = if f x then [] else x :: take_until f xs;
fun is_dict (Const (idx, _)) = (case (Graph.get_node program o the o Inttab.lookup idx_tab) idx
of Code_Thingol.Class _ => true
| Code_Thingol.Classrel _ => true
| Code_Thingol.Classinst _ => true
| _ => false)
| is_dict (DFree _) = true
| is_dict _ = false;
fun const_of_idx idx = (case (Graph.get_node program o the o Inttab.lookup idx_tab) idx
of Code_Thingol.Fun (c, _) => c
| Code_Thingol.Datatypecons (c, _) => c
| Code_Thingol.Classparam (c, _) => c);
fun of_apps bounds (t, ts) =
fold_map (of_univ bounds) ts
#>> (fn ts' => list_comb (t, rev ts'))
and of_univ bounds (Const (idx, ts)) typidx =
let
val ts' = take_until is_dict ts;
val c = const_of_idx idx;
val T = map_type_tvar (fn ((v, i), _) =>
Type_Infer.param typidx (v ^ string_of_int i, []))
(Sign.the_const_type thy c);
val typidx' = typidx + 1;
in of_apps bounds (Term.Const (c, T), ts') typidx' end
| of_univ bounds (BVar (n, ts)) typidx =
of_apps bounds (Bound (bounds - n - 1), ts) typidx
| of_univ bounds (t as Abs _) typidx =
typidx
|> of_univ (bounds + 1) (apps t [BVar (bounds, [])])
|-> (fn t' => pair (Term.Abs ("u", dummyT, t')))
in of_univ 0 t 0 |> fst end;
(* function store *)
structure Nbe_Functions = Code_Data
(
type T = (Univ option * int) Graph.T * (int * string Inttab.table);
val empty = (Graph.empty, (0, Inttab.empty));
);
(* compilation, evaluation and reification *)
fun compile_eval thy program vs_t deps =
let
val ctxt = ProofContext.init_global thy;
val (gr, (_, idx_tab)) =
Nbe_Functions.change thy (ensure_stmts ctxt program);
in
vs_t
|> eval_term ctxt gr deps
|> term_of_univ thy program idx_tab
end;
(* evaluation with type reconstruction *)
fun normalize thy program ((vs0, (vs, ty)), t) deps =
let
val ty' = typ_of_itype program vs0 ty;
fun type_infer t =
singleton (Type_Infer.infer_types (Syntax.pp_global thy) (Sign.tsig_of thy) I
(try (Type.strip_sorts o Sign.the_const_type thy)) (K NONE) Name.context 0)
(Type_Infer.constrain ty' t);
fun check_tvars t = if null (Term.add_tvars t []) then t else
error ("Illegal schematic type variables in normalized term: "
^ setmp_CRITICAL show_types true (Syntax.string_of_term_global thy) t);
val string_of_term = setmp_CRITICAL show_types true (Syntax.string_of_term_global thy);
in
compile_eval thy program (vs, t) deps
|> traced (fn t => "Normalized:\n" ^ string_of_term t)
|> type_infer
|> traced (fn t => "Types inferred:\n" ^ string_of_term t)
|> check_tvars
|> traced (fn _ => "---\n")
end;
(* evaluation oracle *)
fun mk_equals thy lhs raw_rhs =
let
val ty = Thm.typ_of (Thm.ctyp_of_term lhs);
val eq = Thm.cterm_of thy (Term.Const ("==", ty --> ty --> propT));
val rhs = Thm.cterm_of thy raw_rhs;
in Thm.mk_binop eq lhs rhs end;
val (_, raw_norm_oracle) = Context.>>> (Context.map_theory_result
(Thm.add_oracle (Binding.name "norm", fn (thy, program, vsp_ty_t, deps, ct) =>
mk_equals thy ct (normalize thy program vsp_ty_t deps))));
fun norm_oracle thy program vsp_ty_t deps ct =
raw_norm_oracle (thy, program, vsp_ty_t, deps, ct);
fun no_frees_rew rew t =
let
val frees = map Free (Term.add_frees t []);
in
t
|> fold_rev lambda frees
|> rew
|> (fn t' => Term.betapplys (t', frees))
end;
val norm_conv = Code_Simp.no_frees_conv (fn ct =>
let
val thy = Thm.theory_of_cterm ct;
in lift_triv_classes_conv thy (Code_Thingol.eval_conv thy (K (norm_oracle thy))) ct end);
fun norm thy = lift_triv_classes_rew thy (no_frees_rew (Code_Thingol.eval thy I (K (normalize thy))));
(* evaluation command *)
fun norm_print_term ctxt modes t =
let
val thy = ProofContext.theory_of ctxt;
val t' = norm thy t;
val ty' = Term.type_of t';
val ctxt' = Variable.auto_fixes t ctxt;
val p = Print_Mode.with_modes modes (fn () =>
Pretty.block [Pretty.quote (Syntax.pretty_term ctxt' t'), Pretty.fbrk,
Pretty.str "::", Pretty.brk 1, Pretty.quote (Syntax.pretty_typ ctxt' ty')]) ();
in Pretty.writeln p end;
(** Isar setup **)
fun norm_print_term_cmd (modes, s) state =
let val ctxt = Toplevel.context_of state
in norm_print_term ctxt modes (Syntax.read_term ctxt s) end;
val setup = Value.add_evaluator ("nbe", norm o ProofContext.theory_of);
val opt_modes =
Scan.optional (Parse.$$$ "(" |-- Parse.!!! (Scan.repeat1 Parse.xname --| Parse.$$$ ")")) [];
val _ =
Outer_Syntax.improper_command "normal_form" "normalize term by evaluation" Keyword.diag
(opt_modes -- Parse.term >> (Toplevel.keep o norm_print_term_cmd));
end;