src/Pure/Isar/class_declaration.ML
author haftmann
Fri Aug 13 17:17:04 2010 +0200 (2010-08-13)
changeset 38435 1e1ef69ec0de
parent 38390 cb72d89bb444
child 38493 95a41e6ef5a8
permissions -rw-r--r--
corrected handling of `constrains` elements
     1 (*  Title:      Pure/Isar/class_declaration.ML
     2     Author:     Florian Haftmann, TU Muenchen
     3 
     4 Declaring classes and subclass relations.
     5 *)
     6 
     7 signature CLASS_DECLARATION =
     8 sig
     9   val class: binding -> class list -> Element.context_i list
    10     -> theory -> string * local_theory
    11   val class_cmd: binding -> xstring list -> Element.context list
    12     -> theory -> string * local_theory
    13   val prove_subclass: tactic -> class -> local_theory -> local_theory
    14   val subclass: class -> local_theory -> Proof.state
    15   val subclass_cmd: xstring -> local_theory -> Proof.state
    16 end;
    17 
    18 structure Class_Declaration: CLASS_DECLARATION =
    19 struct
    20 
    21 (** class definitions **)
    22 
    23 local
    24 
    25 (* calculating class-related rules including canonical interpretation *)
    26 
    27 fun calculate thy class sups base_sort param_map assm_axiom =
    28   let
    29     val empty_ctxt = ProofContext.init_global thy;
    30 
    31     (* instantiation of canonical interpretation *)
    32     val aT = TFree (Name.aT, base_sort);
    33     val param_map_const = (map o apsnd) Const param_map;
    34     val param_map_inst = (map o apsnd)
    35       (Const o apsnd (map_atyps (K aT))) param_map;
    36     val const_morph = Element.inst_morphism thy
    37       (Symtab.empty, Symtab.make param_map_inst);
    38     val typ_morph = Element.inst_morphism thy
    39       (Symtab.empty |> Symtab.update (Name.aT, TFree (Name.aT, [class])), Symtab.empty);
    40     val (([raw_props], [(_, raw_inst_morph)], export_morph), _) = empty_ctxt
    41       |> Expression.cert_goal_expression ([(class, (("", false),
    42            Expression.Named param_map_const))], []);
    43     val (props, inst_morph) = if null param_map
    44       then (raw_props |> map (Morphism.term typ_morph),
    45         raw_inst_morph $> typ_morph)
    46       else (raw_props, raw_inst_morph); (*FIXME proper handling in
    47         locale.ML / expression.ML would be desirable*)
    48 
    49     (* witness for canonical interpretation *)
    50     val prop = try the_single props;
    51     val wit = Option.map (fn prop => let
    52         val sup_axioms = map_filter (fst o Class.rules thy) sups;
    53         val loc_intro_tac = case Locale.intros_of thy class
    54           of (_, NONE) => all_tac
    55            | (_, SOME intro) => ALLGOALS (Tactic.rtac intro);
    56         val tac = loc_intro_tac
    57           THEN ALLGOALS (ProofContext.fact_tac (sup_axioms @ the_list assm_axiom))
    58       in Element.prove_witness empty_ctxt prop tac end) prop;
    59     val axiom = Option.map Element.conclude_witness wit;
    60 
    61     (* canonical interpretation *)
    62     val base_morph = inst_morph
    63       $> Morphism.binding_morphism (Binding.prefix false (Class.class_prefix class))
    64       $> Element.satisfy_morphism (the_list wit);
    65     val eq_morph = Element.eq_morphism thy (Class.these_defs thy sups);
    66 
    67     (* assm_intro *)
    68     fun prove_assm_intro thm =
    69       let
    70         val ((_, [thm']), _) = Variable.import true [thm] empty_ctxt;
    71         val const_eq_morph = case eq_morph
    72          of SOME eq_morph => const_morph $> eq_morph
    73           | NONE => const_morph
    74         val thm'' = Morphism.thm const_eq_morph thm';
    75         val tac = ALLGOALS (ProofContext.fact_tac [thm'']);
    76       in Skip_Proof.prove_global thy [] [] (Thm.prop_of thm'') (K tac) end;
    77     val assm_intro = Option.map prove_assm_intro
    78       (fst (Locale.intros_of thy class));
    79 
    80     (* of_class *)
    81     val of_class_prop_concl = Logic.mk_of_class (aT, class);
    82     val of_class_prop = case prop of NONE => of_class_prop_concl
    83       | SOME prop => Logic.mk_implies (Morphism.term const_morph
    84           ((map_types o map_atyps) (K aT) prop), of_class_prop_concl);
    85     val sup_of_classes = map (snd o Class.rules thy) sups;
    86     val loc_axiom_intros = map Drule.export_without_context_open (Locale.axioms_of thy class);
    87     val axclass_intro = #intro (AxClass.get_info thy class);
    88     val base_sort_trivs = Thm.of_sort (Thm.ctyp_of thy aT, base_sort);
    89     val tac = REPEAT (SOMEGOAL
    90       (Tactic.match_tac (axclass_intro :: sup_of_classes
    91          @ loc_axiom_intros @ base_sort_trivs)
    92            ORELSE' Tactic.assume_tac));
    93     val of_class = Skip_Proof.prove_global thy [] [] of_class_prop (K tac);
    94 
    95   in (base_morph, eq_morph, export_morph, axiom, assm_intro, of_class) end;
    96 
    97 
    98 (* reading and processing class specifications *)
    99 
   100 fun prep_class_elems prep_decl thy sups raw_elems =
   101   let
   102 
   103     (* user space type system: only permits 'a type variable, improves towards 'a *)
   104     val algebra = Sign.classes_of thy;
   105     val inter_sort = curry (Sorts.inter_sort algebra);
   106     val proto_base_sort = if null sups then Sign.defaultS thy
   107       else fold inter_sort (map (Class.base_sort thy) sups) [];
   108     val base_constraints = (map o apsnd)
   109       (map_type_tfree (K (TVar ((Name.aT, 0), proto_base_sort))) o fst o snd)
   110         (Class.these_operations thy sups);
   111     val reject_bcd_etc = (map o map_atyps) (fn T as TFree (v, sort) =>
   112           if v = Name.aT then T
   113           else error ("No type variable other than " ^ Name.aT ^ " allowed in class specification")
   114       | T => T);
   115     fun singleton_fixate Ts =
   116       let
   117         fun extract f = (fold o fold_atyps) f Ts [];
   118         val tfrees = extract
   119           (fn TFree (v, sort) => insert (op =) (v, sort) | _ => I);
   120         val inferred_sort = extract
   121           (fn TVar (_, sort) => inter_sort sort | _ => I);
   122         val fixate_sort = if null tfrees then inferred_sort
   123           else case tfrees
   124            of [(_, a_sort)] => if Sorts.sort_le algebra (a_sort, inferred_sort)
   125                 then inter_sort a_sort inferred_sort
   126                 else error ("Type inference imposes additional sort constraint "
   127                   ^ Syntax.string_of_sort_global thy inferred_sort
   128                   ^ " of type parameter " ^ Name.aT ^ " of sort "
   129                   ^ Syntax.string_of_sort_global thy a_sort ^ ".")
   130             | _ => error "Multiple type variables in class specification.";
   131       in (map o map_atyps) (K (TFree (Name.aT, fixate_sort))) Ts end;
   132     fun add_typ_check level name f = Context.proof_map
   133       (Syntax.add_typ_check level name (fn Ts => fn ctxt =>
   134         let val Ts' = f Ts in if eq_list (op =) (Ts, Ts') then NONE else SOME (Ts', ctxt) end));
   135 
   136     (* preprocessing elements, retrieving base sort from type-checked elements *)
   137     val init_class_body = fold (ProofContext.add_const_constraint o apsnd SOME) base_constraints
   138       #> Class.redeclare_operations thy sups
   139       #> add_typ_check 10 "reject_bcd_etc" reject_bcd_etc
   140       #> add_typ_check ~10 "singleton_fixate" singleton_fixate;
   141     val raw_supexpr = (map (fn sup => (sup, (("", false),
   142       Expression.Positional []))) sups, []);
   143     val ((raw_supparams, _, raw_inferred_elems), _) = ProofContext.init_global thy
   144       |> prep_decl raw_supexpr init_class_body raw_elems;
   145     fun filter_element (Element.Fixes []) = NONE
   146       | filter_element (e as Element.Fixes _) = SOME e
   147       | filter_element (Element.Constrains []) = NONE
   148       | filter_element (e as Element.Constrains _) = SOME e
   149       | filter_element (Element.Assumes []) = NONE
   150       | filter_element (e as Element.Assumes _) = SOME e
   151       | filter_element (Element.Defines _) = error ("\"defines\" element not allowed in class specification.")
   152       | filter_element (Element.Notes _) = error ("\"notes\" element not allowed in class specification.");
   153     val inferred_elems = map_filter filter_element raw_inferred_elems;
   154     fun fold_element_types f (Element.Fixes fxs) = fold (fn (_, SOME T, _) => f T) fxs
   155       | fold_element_types f (Element.Constrains cnstrs) = fold (f o snd) cnstrs
   156       | fold_element_types f (Element.Assumes assms) = fold (fold (fn (t, ts) =>
   157           fold_types f t #> (fold o fold_types) f ts) o snd) assms
   158     val base_sort = if null inferred_elems then proto_base_sort else
   159       case (fold o fold_element_types) Term.add_tfreesT inferred_elems []
   160        of [] => error "No type variable in class specification"
   161         | [(_, sort)] => sort
   162         | _ => error "Multiple type variables in class specification";
   163     val supparams = map (fn ((c, T), _) =>
   164       (c, map_atyps (K (TFree (Name.aT, base_sort))) T)) raw_supparams;
   165     val supparam_names = map fst supparams;
   166     fun mk_param ((c, _), _) = Free (c, (the o AList.lookup (op =) supparams) c);
   167     val supexpr = (map (fn sup => (sup, (("", false),
   168       Expression.Positional (map (SOME o mk_param) (Locale.params_of thy sup))))) sups,
   169         map (fn (c, T) => (Binding.name c, SOME T, NoSyn)) supparams);
   170 
   171   in (base_sort, supparam_names, supexpr, inferred_elems) end;
   172 
   173 val cert_class_elems = prep_class_elems Expression.cert_declaration;
   174 val read_class_elems = prep_class_elems Expression.cert_read_declaration;
   175 
   176 fun prep_class_spec prep_class prep_class_elems thy raw_supclasses raw_elems =
   177   let
   178 
   179     (* prepare import *)
   180     val inter_sort = curry (Sorts.inter_sort (Sign.classes_of thy));
   181     val sups = map (prep_class thy) raw_supclasses
   182       |> Sign.minimize_sort thy;
   183     val _ = case filter_out (Class.is_class thy) sups
   184      of [] => ()
   185       | no_classes => error ("No (proper) classes: " ^ commas (map quote no_classes));
   186     val raw_supparams = (map o apsnd) (snd o snd) (Class.these_params thy sups);
   187     val raw_supparam_names = map fst raw_supparams;
   188     val _ = if has_duplicates (op =) raw_supparam_names
   189       then error ("Duplicate parameter(s) in superclasses: "
   190         ^ (commas o map quote o duplicates (op =)) raw_supparam_names)
   191       else ();
   192 
   193     (* infer types and base sort *)
   194     val (base_sort, supparam_names, supexpr, inferred_elems) =
   195       prep_class_elems thy sups raw_elems;
   196     val sup_sort = inter_sort base_sort sups;
   197 
   198     (* process elements as class specification *)
   199     val class_ctxt = Class.begin sups base_sort (ProofContext.init_global thy);
   200     val ((_, _, syntax_elems), _) = class_ctxt
   201       |> Expression.cert_declaration supexpr I inferred_elems;
   202     fun check_vars e vs = if null vs
   203       then error ("No type variable in part of specification element "
   204         ^ (Pretty.string_of o Pretty.chunks) (Element.pretty_ctxt class_ctxt e))
   205       else ();
   206     fun check_element (e as Element.Fixes fxs) =
   207           map (fn (_, SOME T, _) => check_vars e (Term.add_tfreesT T [])) fxs
   208       | check_element (e as Element.Assumes assms) =
   209           maps (fn (_, ts_pss) => map
   210             (fn (t, _) => check_vars e (Term.add_tfrees t [])) ts_pss) assms
   211       | check_element e = [()];
   212     val _ = map check_element syntax_elems;
   213     fun fork_syn (Element.Fixes xs) =
   214           fold_map (fn (c, ty, syn) => cons (c, syn) #> pair (c, ty, NoSyn)) xs
   215           #>> Element.Fixes
   216       | fork_syn x = pair x;
   217     val (elems, global_syntax) = fold_map fork_syn syntax_elems [];
   218 
   219   in (((sups, supparam_names), (sup_sort, base_sort, supexpr)), (elems, global_syntax)) end;
   220 
   221 val cert_class_spec = prep_class_spec (K I) cert_class_elems;
   222 val read_class_spec = prep_class_spec Sign.intern_class read_class_elems;
   223 
   224 
   225 (* class establishment *)
   226 
   227 fun add_consts class base_sort sups supparam_names global_syntax thy =
   228   let
   229     (*FIXME simplify*)
   230     val supconsts = supparam_names
   231       |> AList.make (snd o the o AList.lookup (op =) (Class.these_params thy sups))
   232       |> (map o apsnd o apsnd o map_atyps o K o TFree) (Name.aT, [class]);
   233     val all_params = Locale.params_of thy class;
   234     val raw_params = (snd o chop (length supparam_names)) all_params;
   235     fun add_const ((raw_c, raw_ty), _) thy =
   236       let
   237         val b = Binding.name raw_c;
   238         val c = Sign.full_name thy b;
   239         val ty = map_atyps (K (TFree (Name.aT, base_sort))) raw_ty;
   240         val ty0 = Type.strip_sorts ty;
   241         val ty' = map_atyps (K (TFree (Name.aT, [class]))) ty0;
   242         val syn = (the_default NoSyn o AList.lookup Binding.eq_name global_syntax) b;
   243       in
   244         thy
   245         |> Sign.declare_const ((b, ty0), syn)
   246         |> snd
   247         |> pair ((Name.of_binding b, ty), (c, ty'))
   248       end;
   249   in
   250     thy
   251     |> Sign.add_path (Class.class_prefix class)
   252     |> fold_map add_const raw_params
   253     ||> Sign.restore_naming thy
   254     |-> (fn params => pair (supconsts @ (map o apfst) fst params, params))
   255   end;
   256 
   257 fun adjungate_axclass bname class base_sort sups supsort supparam_names global_syntax thy =
   258   let
   259     (*FIXME simplify*)
   260     fun globalize param_map = map_aterms
   261       (fn Free (v, ty) => Const ((fst o the o AList.lookup (op =) param_map) v, ty)
   262         | t => t);
   263     val raw_pred = Locale.intros_of thy class
   264       |> fst
   265       |> Option.map (Logic.unvarify_global o Logic.strip_imp_concl o Thm.prop_of);
   266     fun get_axiom thy = case (#axioms o AxClass.get_info thy) class
   267      of [] => NONE
   268       | [thm] => SOME thm;
   269   in
   270     thy
   271     |> add_consts class base_sort sups supparam_names global_syntax
   272     |-> (fn (param_map, params) => AxClass.define_class (bname, supsort)
   273           (map (fst o snd) params)
   274           [(Thm.empty_binding, Option.map (globalize param_map) raw_pred |> the_list)]
   275     #> snd
   276     #> `get_axiom
   277     #-> (fn assm_axiom => fold (Sign.add_const_constraint o apsnd SOME o snd) params
   278     #> pair (param_map, params, assm_axiom)))
   279   end;
   280 
   281 fun gen_class prep_class_spec b raw_supclasses raw_elems thy =
   282   let
   283     val class = Sign.full_name thy b;
   284     val (((sups, supparam_names), (supsort, base_sort, supexpr)), (elems, global_syntax)) =
   285       prep_class_spec thy raw_supclasses raw_elems;
   286   in
   287     thy
   288     |> Expression.add_locale b (Binding.qualify true "class" b) supexpr elems
   289     |> snd |> Local_Theory.exit_global
   290     |> adjungate_axclass b class base_sort sups supsort supparam_names global_syntax
   291     ||> Theory.checkpoint
   292     |-> (fn (param_map, params, assm_axiom) =>
   293        `(fn thy => calculate thy class sups base_sort param_map assm_axiom)
   294     #-> (fn (base_morph, eq_morph, export_morph, axiom, assm_intro, of_class) =>
   295        Context.theory_map (Locale.add_registration (class, base_morph)
   296          (Option.map (rpair true) eq_morph) export_morph)
   297     #> Class.register class sups params base_sort base_morph export_morph axiom assm_intro of_class))
   298     |> Named_Target.init class
   299     |> pair class
   300   end;
   301 
   302 in
   303 
   304 val class = gen_class cert_class_spec;
   305 val class_cmd = gen_class read_class_spec;
   306 
   307 end; (*local*)
   308 
   309 
   310 (** subclass relations **)
   311 
   312 local
   313 
   314 fun gen_subclass prep_class do_proof raw_sup lthy =
   315   let
   316     val thy = ProofContext.theory_of lthy;
   317     val proto_sup = prep_class thy raw_sup;
   318     val proto_sub = case Named_Target.peek lthy
   319      of SOME {target, is_class = true, ...} => target
   320       | _ => error "Not in a class target";
   321     val (sub, sup) = AxClass.cert_classrel thy (proto_sub, proto_sup);
   322 
   323     val expr = ([(sup, (("", false), Expression.Positional []))], []);
   324     val (([props], deps, export), goal_ctxt) =
   325       Expression.cert_goal_expression expr lthy;
   326     val some_prop = try the_single props;
   327     val some_dep_morph = try the_single (map snd deps);
   328     fun after_qed some_wit =
   329       ProofContext.theory (Class.register_subclass (sub, sup)
   330         some_dep_morph some_wit export)
   331       #> ProofContext.theory_of #> Named_Target.init sub;
   332   in do_proof after_qed some_prop goal_ctxt end;
   333 
   334 fun user_proof after_qed some_prop =
   335   Element.witness_proof (after_qed o try the_single o the_single)
   336     [the_list some_prop];
   337 
   338 fun tactic_proof tac after_qed some_prop ctxt =
   339   after_qed (Option.map
   340     (fn prop => Element.prove_witness ctxt prop tac) some_prop) ctxt;
   341 
   342 in
   343 
   344 val subclass = gen_subclass (K I) user_proof;
   345 fun prove_subclass tac = gen_subclass (K I) (tactic_proof tac);
   346 val subclass_cmd = gen_subclass (ProofContext.read_class o ProofContext.init_global) user_proof;
   347 
   348 end; (*local*)
   349 
   350 end;