(*  Title:      Pure/Isar/locale.ML

     Author:     Clemens Ballarin, TU Muenchen

 Locales -- managed Isar proof contexts, based on Pure predicates.

 Draws basic ideas from Florian Kammueller's original version of

 locales, but uses the richer infrastructure of Isar instead of the raw

 meta-logic.  Furthermore, structured import of contexts (with merge

 and rename operations) are provided, as well as type-inference of the

 signature parts, and predicate definitions of the specification text.

 Interpretation enables the reuse of theorems of locales in other

 contexts, namely those defined by theories, structured proofs and

 locales themselves.

 See also:

 [1] Clemens Ballarin. Locales and Locale Expressions in Isabelle/Isar.

     In Stefano Berardi et al., Types for Proofs and Programs: International

     Workshop, TYPES 2003, Torino, Italy, LNCS 3085, pages 34-50, 2004.

 [2] Clemens Ballarin. Interpretation of Locales in Isabelle: Managing

     Dependencies between Locales. Technical Report TUM-I0607, Technische

     Universitaet Muenchen, 2006.

 [3] Clemens Ballarin. Interpretation of Locales in Isabelle: Theories and

     Proof Contexts. In J.M. Borwein and W.M. Farmer, MKM 2006, LNAI 4108,

     pages 31-43, 2006.

 *)

 signature LOCALE =

 sig

   (* Locale specification *)

   val register_locale: binding ->

     (string * sort) list * ((string * typ) * mixfix) list ->

     term option * term list ->

     thm option * thm option -> thm list ->

     declaration list ->

     (string * (Attrib.binding * (thm list * Attrib.src list) list) list) list ->

     (string * morphism) list -> theory -> theory

   val intern: theory -> xstring -> string

   val extern: theory -> string -> xstring

   val defined: theory -> string -> bool

   val params_of: theory -> string -> ((string * typ) * mixfix) list

   val intros_of: theory -> string -> thm option * thm option

   val axioms_of: theory -> string -> thm list

   val instance_of: theory -> string -> morphism -> term list

   val specification_of: theory -> string -> term option * term list

   (* Storing results *)

   val add_thmss: string -> string -> (Attrib.binding * (thm list * Attrib.src list) list) list ->

     Proof.context -> Proof.context

   val add_declaration: string -> declaration -> Proof.context -> Proof.context

   val add_syntax_declaration: string -> declaration -> Proof.context -> Proof.context

   (* Activation *)

   val activate_declarations: string * morphism -> Proof.context -> Proof.context

   val activate_facts: morphism option -> string * morphism -> Context.generic -> Context.generic

   val init: string -> theory -> Proof.context

   (* Reasoning about locales *)

   val get_witnesses: Proof.context -> thm list

   val get_intros: Proof.context -> thm list

   val get_unfolds: Proof.context -> thm list

   val witness_add: attribute

   val intro_add: attribute

   val unfold_add: attribute

   val intro_locales_tac: bool -> Proof.context -> thm list -> tactic

   (* Registrations and dependencies *)

   val add_registration: string * morphism -> (morphism * bool) option ->

     morphism -> Context.generic -> Context.generic

   val amend_registration: string * morphism -> morphism * bool ->

     morphism -> Context.generic -> Context.generic

   val registrations_of: Context.generic -> string -> (string * morphism) list

   val add_dependency: string -> string * morphism -> morphism -> theory -> theory

   (* Diagnostic *)

   val all_locales: theory -> string list

   val print_locales: theory -> unit

   val print_locale: theory -> bool -> xstring -> unit

   val print_registrations: Proof.context -> string -> unit

   val locale_deps: theory ->

     { params: ((string * typ) * mixfix) list, axioms: term list, registrations: term list list } Graph.T

       * term list list Symtab.table Symtab.table

 end;

 structure Locale: LOCALE =

 struct

 datatype ctxt = datatype Element.ctxt;

 (*** Locales ***)

 datatype locale = Loc of {

   (** static part **)

   parameters: (string * sort) list * ((string * typ) * mixfix) list,

     (* type and term parameters *)

   spec: term option * term list,

     (* assumptions (as a single predicate expression) and defines *)

   intros: thm option * thm option,

   axioms: thm list,

   (** dynamic part **)

   syntax_decls: (declaration * serial) list,

     (* syntax declarations *)

   notes: ((string * (Attrib.binding * (thm list * Attrib.src list) list) list) * serial) list,

     (* theorem declarations *)

   dependencies: ((string * (morphism * morphism)) * serial) list

     (* locale dependencies (sublocale relation) *)

 };

 fun mk_locale ((parameters, spec, intros, axioms), ((syntax_decls, notes), dependencies)) =

   Loc {parameters = parameters, intros = intros, axioms = axioms, spec = spec,

     syntax_decls = syntax_decls, notes = notes, dependencies = dependencies};

 fun map_locale f (Loc {parameters, spec, intros, axioms, syntax_decls, notes, dependencies}) =

   mk_locale (f ((parameters, spec, intros, axioms), ((syntax_decls, notes), dependencies)));

 fun merge_locale

  (Loc {parameters, spec, intros, axioms, syntax_decls, notes, dependencies},

   Loc {syntax_decls = syntax_decls', notes = notes', dependencies = dependencies', ...}) =

     mk_locale

       ((parameters, spec, intros, axioms),

         ((merge (eq_snd op =) (syntax_decls, syntax_decls'),

           merge (eq_snd op =) (notes, notes')),

             merge (eq_snd op =) (dependencies, dependencies')));

 structure Locales = Theory_Data

 (

   type T = locale Name_Space.table;

   val empty : T = Name_Space.empty_table "locale";

   val extend = I;

   val merge = Name_Space.join_tables (K merge_locale);

 );

 val intern = Name_Space.intern o #1 o Locales.get;

 val extern = Name_Space.extern o #1 o Locales.get;

 val get_locale = Symtab.lookup o #2 o Locales.get;

 val defined = Symtab.defined o #2 o Locales.get;

 fun the_locale thy name =

   (case get_locale thy name of

     SOME (Loc loc) => loc

   | NONE => error ("Unknown locale " ^ quote name));

 fun register_locale binding parameters spec intros axioms syntax_decls notes dependencies thy =

   thy |> Locales.map (Name_Space.define true (Sign.naming_of thy)

     (binding,

       mk_locale ((parameters, spec, intros, axioms),

         ((map (fn decl => (decl, serial ())) syntax_decls, map (fn n => (n, serial ())) notes),

           map (fn d => (d |> apsnd (rpair Morphism.identity), serial ())) dependencies))) #> snd);

           (* FIXME *)

 fun change_locale name =

   Locales.map o apsnd o Symtab.map_entry name o map_locale o apsnd;

 (** Primitive operations **)

 fun params_of thy = snd o #parameters o the_locale thy;

 fun intros_of thy = #intros o the_locale thy;

 fun axioms_of thy = #axioms o the_locale thy;

 fun instance_of thy name morph = params_of thy name |>

   map (Morphism.term morph o Free o #1);

 fun specification_of thy = #spec o the_locale thy;

 fun dependencies_of thy name = the_locale thy name |>

   #dependencies |> map fst;

 (* Print instance and qualifiers *)

 fun pretty_reg thy (name, morph) =

   let

     val name' = extern thy name;

     val ctxt = ProofContext.init_global thy;

     fun prt_qual (qual, mand) = Pretty.str (qual ^ (if mand then "!" else "?"));

     fun prt_quals qs = Pretty.separate "." (map prt_qual qs) |> Pretty.block;

     val prt_term = Pretty.quote o Syntax.pretty_term ctxt;

     fun prt_term' t = if !show_types

       then Pretty.block [prt_term t, Pretty.brk 1, Pretty.str "::",

         Pretty.brk 1, (Pretty.quote o Syntax.pretty_typ ctxt) (type_of t)]

       else prt_term t;

     fun prt_inst ts =

       Pretty.block (Pretty.breaks (Pretty.str name' :: map prt_term' ts));

     val qs = Binding.name "x" |> Morphism.binding morph |> Binding.prefix_of;

     val ts = instance_of thy name morph;

   in

     case qs of

        [] => prt_inst ts

      | qs => Pretty.block [prt_quals qs, Pretty.brk 1, Pretty.str ":",

          Pretty.brk 1, prt_inst ts]

   end;

 (*** Identifiers: activated locales in theory or proof context ***)

 (* subsumption *)

 fun ident_le thy ((n: string, ts), (m, ss)) = (m = n) andalso Pattern.matchess thy (ss, ts);

   (* smaller term is more general *)

 (* total order *)

 fun ident_ord ((n: string, ts), (m, ss)) =

   case fast_string_ord (m, n) of

       EQUAL => list_ord Term_Ord.fast_term_ord (ts, ss)

     | ord => ord;

 local

 datatype 'a delayed = Ready of 'a | ToDo of 'a delayed * 'a delayed;

 structure Identifiers = Generic_Data

 (

   type T = (string * term list) list delayed;

   val empty = Ready [];

   val extend = I;

   val merge = ToDo;

 );

 fun finish thy (ToDo (i1, i2)) = merge (ident_le thy) (finish thy i1, finish thy i2)

   | finish _ (Ready ids) = ids;

 val _ = Context.>> (Context.map_theory (Theory.at_begin (fn thy =>

   (case Identifiers.get (Context.Theory thy) of

     Ready _ => NONE

   | ids => SOME (Context.theory_map (Identifiers.put (Ready (finish thy ids))) thy)))));

 in

 val get_idents = (fn Ready ids => ids) o Identifiers.get;

 val put_idents = Identifiers.put o Ready;

 end;

 (** Resolve locale dependencies in a depth-first fashion **)

 local

 val roundup_bound = 120;

 fun add thy depth export (name, morph) (deps, marked) =

   if depth > roundup_bound

   then error "Roundup bound exceeded (sublocale relation probably not terminating)."

   else

     let

       val dependencies = dependencies_of thy name;

       val instance = instance_of thy name (morph $> export);

     in

       if member (ident_le thy) marked (name, instance)

       then (deps, marked)

       else

         let

           val dependencies' = map (fn (name, (morph', export')) => (name, morph' $> export' $> morph)) dependencies;

           val marked' = (name, instance) :: marked;

           val (deps', marked'') = fold_rev (add thy (depth + 1) export) dependencies' ([], marked');

         in

           ((name, morph) :: deps' @ deps, marked'')

         end

     end;

 in

 (* Note that while identifiers always have the external (exported) view, activate_dep

   is presented with the internal view. *)

 fun roundup thy activate_dep export (name, morph) (marked, input) =

   let

     (* Find all dependencies incuding new ones (which are dependencies enriching

       existing registrations). *)

     val (dependencies, marked') = add thy 0 export (name, morph) ([], []);

     (* Filter out fragments from marked; these won't be activated. *)

     val dependencies' = filter_out (fn (name, morph) =>

       member (ident_le thy) marked (name, instance_of thy name (morph $> export))) dependencies;

   in

     (merge (ident_le thy) (marked, marked'), input |> fold_rev activate_dep dependencies')

   end;

 end;

 (*** Registrations: interpretations in theories or proof contexts ***)

 structure Idtab = Table(type key = string * term list val ord = ident_ord);

 structure Registrations = Generic_Data

 (

   type T = ((morphism * morphism) * serial) Idtab.table *

     (* registrations, indexed by locale name and instance;

        serial points to mixin list *)

     (((morphism * bool) * serial) list) Inttab.table;

     (* table of mixin lists, per list mixins in reverse order of declaration;

        lists indexed by registration serial,

        entries for empty lists may be omitted *)

   val empty = (Idtab.empty, Inttab.empty);

   val extend = I;

   fun merge ((reg1, mix1), (reg2, mix2)) : T =

     (Idtab.join (fn id => fn (r1 as (_, s1), r2 as (_, s2)) =>

         if s1 = s2 then raise Idtab.SAME else raise Idtab.DUP id) (reg1, reg2),

       Inttab.join (K (Library.merge (eq_snd op =))) (mix1, mix2))

     handle Idtab.DUP id =>

       (* distinct interpretations with same base: merge their mixins *)

       let

         val (_, s1) = Idtab.lookup reg1 id |> the;

         val (morph2, s2) = Idtab.lookup reg2 id |> the;

         val reg2' = Idtab.update (id, (morph2, s1)) reg2;

         val mix2' = case Inttab.lookup mix2 s2 of

               NONE => mix2 |

               SOME mxs => Inttab.delete s2 mix2 |> Inttab.update_new (s1, mxs);

         val _ = warning "Removed duplicate interpretation after retrieving its mixins.";

         (* FIXME print interpretations,

            which is not straightforward without theory context *)

       in merge ((reg1, mix1), (reg2', mix2')) end;

     (* FIXME consolidate with dependencies, consider one data slot only *)

 );

 (* Primitive operations *)

 fun add_reg thy export (name, morph) =

   Registrations.map (apfst (Idtab.insert (K false)

     ((name, instance_of thy name (morph $> export)), ((morph, export), serial ()))));

 fun add_mixin serial' mixin =

   (* registration to be amended identified by its serial id *)

   Registrations.map (apsnd (Inttab.map_default (serial', []) (cons (mixin, serial ()))));

 fun get_mixins context (name, morph) =

   let

     val thy = Context.theory_of context;

     val (regs, mixins) = Registrations.get context;

   in

     case Idtab.lookup regs (name, instance_of thy name morph) of

       NONE => []

     | SOME (_, serial) => the_default [] (Inttab.lookup mixins serial)

   end;

 fun compose_mixins mixins =

   fold_rev Morphism.compose (map (fst o fst) mixins) Morphism.identity;

 fun collect_mixins context (name, morph) =

   let

     val thy = Context.theory_of context;

   in

     roundup thy (fn dep => fn mixins => merge (eq_snd op =) (mixins, get_mixins context dep))

       Morphism.identity (name, morph) ([(name, instance_of thy name morph)], [])

     |> snd |> filter (snd o fst)  (* only inheritable mixins *)

     |> (fn x => merge (eq_snd op =) (x, get_mixins context (name, morph)))

     |> compose_mixins

   end;

 fun get_registrations context select = Registrations.get context

   |>> Idtab.dest |>> select

   (* with inherited mixins *)

   |-> (fn regs => fn _ => map (fn ((name, _), ((base, export) ,_)) =>

     (name, base $> (collect_mixins context (name, base $> export)) $> export)) regs);

 fun registrations_of context name =

   get_registrations context (filter (curry (op =) name o fst o fst));

 fun all_registrations context = get_registrations context I;

 (*** Activate context elements of locale ***)

 (* Declarations, facts and entire locale content *)

 fun activate_syntax_decls (name, morph) context =

   let

     val thy = Context.theory_of context;

     val {syntax_decls, ...} = the_locale thy name;

   in

     context

     |> fold_rev (fn (decl, _) => decl morph) syntax_decls

   end;

 fun activate_notes activ_elem transfer context export' (name, morph) input =

   let

     val thy = Context.theory_of context;

     val {notes, ...} = the_locale thy name;

     fun activate ((kind, facts), _) input =

       let

         val mixin = case export' of NONE => Morphism.identity

          | SOME export => collect_mixins context (name, morph $> export) $> export;

         val facts' = facts |> Element.facts_map (Element.morph_ctxt (transfer input $> morph $> mixin))

       in activ_elem (Notes (kind, facts')) input end;

   in

     fold_rev activate notes input

   end;

 fun activate_all name thy activ_elem transfer (marked, input) =

   let

     val {parameters = (_, params), spec = (asm, defs), ...} = the_locale thy name;

     val input' = input |>

       (not (null params) ?

         activ_elem (Fixes (map (fn ((x, T), mx) => (Binding.name x, SOME T, mx)) params))) |>

       (* FIXME type parameters *)

       (case asm of SOME A => activ_elem (Assumes [(Attrib.empty_binding, [(A, [])])]) | _ => I) |>

       (if not (null defs)

         then activ_elem (Defines (map (fn def => (Attrib.empty_binding, (def, []))) defs))

         else I);

     val activate = activate_notes activ_elem transfer (Context.Theory thy) NONE;

   in

     roundup thy activate Morphism.identity (name, Morphism.identity) (marked, input')

   end;

 (** Public activation functions **)

 fun activate_declarations dep = Context.proof_map (fn context =>

   let

     val thy = Context.theory_of context;

   in

     roundup thy activate_syntax_decls Morphism.identity dep (get_idents context, context)

     |-> put_idents

   end);

 fun activate_facts export dep context =

   let

     val thy = Context.theory_of context;

     val activate = activate_notes Element.init (Element.transfer_morphism o Context.theory_of) context export;

   in

     roundup thy activate (case export of NONE => Morphism.identity | SOME export => export)

       dep (get_idents context, context)

     |-> put_idents

   end;

 fun init name thy =

   activate_all name thy Element.init (Element.transfer_morphism o Context.theory_of)

     ([], Context.Proof (ProofContext.init_global thy)) |-> put_idents |> Context.proof_of;

 (*** Add and extend registrations ***)

 fun amend_registration (name, morph) mixin export context =

   let

     val thy = Context.theory_of context;

     val regs = Registrations.get context |> fst;

     val base = instance_of thy name (morph $> export);

   in

     case Idtab.lookup regs (name, base) of

         NONE => error ("No interpretation of locale " ^

           quote (extern thy name) ^ " and\nparameter instantiation " ^

           space_implode " " (map (quote o Syntax.string_of_term_global thy) base) ^

           " available")

       | SOME (_, serial') => add_mixin serial' mixin context

   end;

 (* Note that a registration that would be subsumed by an existing one will not be

    generated, and it will not be possible to amend it. *)

 fun add_registration (name, base_morph) mixin export context =

   let

     val thy = Context.theory_of context;

     val mix = case mixin of NONE => Morphism.identity

           | SOME (mix, _) => mix;

     val morph = base_morph $> mix;

     val inst = instance_of thy name morph;

   in

     if member (ident_le thy) (get_idents context) (name, inst)

     then context

     else

       (get_idents context, context)

       (* add new registrations with inherited mixins *)

       |> roundup thy (add_reg thy export) export (name, morph)

       |> snd

       (* add mixin *)

       |> (case mixin of NONE => I

            | SOME mixin => amend_registration (name, morph) mixin export)

       (* activate import hierarchy as far as not already active *)

       |> activate_facts (SOME export) (name, morph)

   end;

 (*** Dependencies ***)

 fun add_dependency loc (name, morph) export thy =

   let

     val thy' = (change_locale loc o apsnd) (cons ((name, (morph, export)), serial ())) thy;

     val context' = Context.Theory thy';

     val (_, regs) = fold_rev (roundup thy' cons export)

       (all_registrations context') (get_idents (context'), []);

   in

     thy'

     |> fold_rev (fn dep => Context.theory_map (add_registration dep NONE export)) regs

   end;

 (*** Storing results ***)

 (* Theorems *)

 fun add_thmss loc kind args ctxt =

   let

     val (Notes args', ctxt') = Element.activate_i (Notes (kind, args)) ctxt;

     val ctxt'' = ctxt' |> ProofContext.background_theory

      ((change_locale loc o apfst o apsnd) (cons (args', serial ()))

         #>

       (* Registrations *)

       (fn thy => fold_rev (fn (_, morph) =>

             let

               val args'' = snd args' |> Element.facts_map (Element.morph_ctxt morph) |>

                 Attrib.map_facts (Attrib.attribute_i thy)

             in PureThy.note_thmss kind args'' #> snd end)

         (registrations_of (Context.Theory thy) loc) thy))

   in ctxt'' end;

 (* Declarations *)

 fun add_declaration loc decl =

   add_thmss loc ""

     [((Binding.conceal Binding.empty,

         [Attrib.internal (fn phi => Thm.declaration_attribute (K (decl phi)))]),

       [([Drule.dummy_thm], [])])];

 fun add_syntax_declaration loc decl =

   ProofContext.background_theory ((change_locale loc o apfst o apfst) (cons (decl, serial ())))

   #> add_declaration loc decl;

 (*** Reasoning about locales ***)

 (* Storage for witnesses, intro and unfold rules *)

 structure Thms = Generic_Data

 (

   type T = thm list * thm list * thm list;

   val empty = ([], [], []);

   val extend = I;

   fun merge ((witnesses1, intros1, unfolds1), (witnesses2, intros2, unfolds2)) =

    (Thm.merge_thms (witnesses1, witnesses2),

     Thm.merge_thms (intros1, intros2),

     Thm.merge_thms (unfolds1, unfolds2));

 );

 val get_witnesses = #1 o Thms.get o Context.Proof;

 val get_intros = #2 o Thms.get o Context.Proof;

 val get_unfolds = #3 o Thms.get o Context.Proof;

 val witness_add =

   Thm.declaration_attribute (fn th => Thms.map (fn (x, y, z) => (Thm.add_thm th x, y, z)));

 val intro_add =

   Thm.declaration_attribute (fn th => Thms.map (fn (x, y, z) => (x, Thm.add_thm th y, z)));

 val unfold_add =

   Thm.declaration_attribute (fn th => Thms.map (fn (x, y, z) => (x, y, Thm.add_thm th z)));

 (* Tactic *)

 fun gen_intro_locales_tac intros_tac eager ctxt =

   intros_tac

     (get_witnesses ctxt @ get_intros ctxt @ (if eager then get_unfolds ctxt else []));

 val intro_locales_tac = gen_intro_locales_tac Method.intros_tac;

 val try_intro_locales_tac= gen_intro_locales_tac Method.try_intros_tac;

 val _ = Context.>> (Context.map_theory

  (Method.setup (Binding.name "intro_locales") (Scan.succeed (METHOD o try_intro_locales_tac false))

     "back-chain introduction rules of locales without unfolding predicates" #>

   Method.setup (Binding.name "unfold_locales") (Scan.succeed (METHOD o try_intro_locales_tac true))

     "back-chain all introduction rules of locales"));

 (*** diagnostic commands and interfaces ***)

 val all_locales = Symtab.keys o snd o Locales.get;

 fun print_locales thy =

   Pretty.strs ("locales:" :: map #1 (Name_Space.extern_table (Locales.get thy)))

   |> Pretty.writeln;

 fun print_locale thy show_facts raw_name =

   let

     val name = intern thy raw_name;

     val ctxt = init name thy;

     fun cons_elem (elem as Notes _) = show_facts ? cons elem

       | cons_elem elem = cons elem;

     val elems =

       activate_all name thy cons_elem (K (Element.transfer_morphism thy)) ([], [])

       |> snd |> rev;

   in

     Pretty.big_list "locale elements:" (map (Pretty.chunks o Element.pretty_ctxt ctxt) elems)

     |> Pretty.writeln

   end;

 fun print_registrations ctxt raw_name =

   let

     val thy = ProofContext.theory_of ctxt;

   in

     (case registrations_of  (Context.Proof ctxt) (* FIXME *) (intern thy raw_name) of

         [] => Pretty.str ("no interpretations")

       | regs => Pretty.big_list "interpretations:" (map (pretty_reg thy) (rev regs)))

     |> Pretty.writeln

   end;

 fun locale_deps thy =

   let

     val names = all_locales thy

     fun add_locale_node name =

       let

         val params = params_of thy name;

         val axioms = (these o Option.map (Logic.strip_imp_prems o Thm.prop_of) o fst o intros_of thy) name;

         val registrations = map (instance_of thy name o snd)

           (registrations_of (Context.Theory thy) name);

       in 

         Graph.new_node (name, { params = params, axioms = axioms, registrations = registrations })

       end;

     fun add_locale_deps name =

       let

         val dependencies = (map o apsnd) (instance_of thy name o op $>)

           (dependencies_of thy name);

       in

         fold (fn (super, ts) => fn (gr, deps) => (gr |> Graph.add_edge (super, name),

           deps |> Symtab.map_default (super, Symtab.empty) (Symtab.cons_list (name, ts))))

             dependencies

       end;

   in

     Graph.empty

     |> fold add_locale_node names

     |> rpair Symtab.empty

     |> fold add_locale_deps names

   end;

 end;