(*  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 * 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

   val declarations_of: theory -> string -> declaration list * declaration list

   val dependencies_of: theory -> string -> (string * morphism) list

   (* Storing results *)

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

     Proof.context -> Proof.context

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

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

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

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

   (* Activation *)

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

   val activate_facts: 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 *)

   val add_registration: string * (morphism * morphism) -> theory -> theory

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

   val get_registrations: theory -> (string * morphism) list

   (* Diagnostic *)

   val print_locales: theory -> unit

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

 end;

 structure Locale: LOCALE =

 struct

 datatype ctxt = datatype Element.ctxt;

 (*** Theory data ***)

 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 **)

   decls: (declaration * stamp) list * (declaration * stamp) list,

     (* type and term syntax declarations *)

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

     (* theorem declarations *)

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

     (* locale dependencies (sublocale relation) *)

 };

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

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

     decls = decls, notes = notes, dependencies = dependencies};

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

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

 fun merge_locale (Loc {parameters, spec, intros, axioms, decls = (decls1, decls2),

   notes, dependencies}, Loc {decls = (decls1', decls2'), notes = notes',

     dependencies = dependencies', ...}) = mk_locale

       ((parameters, spec, intros, axioms),

         (((merge (eq_snd op =) (decls1, decls1'), merge (eq_snd op =) (decls2, decls2')),

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

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

 structure Locales = TheoryDataFun

 (

   type T = locale NameSpace.table;

   val empty = NameSpace.empty_table;

   val copy = I;

   val extend = I;

   fun merge _ = NameSpace.join_tables (K merge_locale);

 );

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

 val extern = NameSpace.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 decls notes dependencies thy =

   thy |> Locales.map (NameSpace.define (Sign.naming_of thy)

     (binding,

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

         ((pairself (map (fn decl => (decl, stamp ()))) decls, map (fn n => (n, stamp ())) notes),

           map (fn d => (d, stamp ())) dependencies))) #> snd);

 fun change_locale name =

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

 fun print_locales thy =

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

   |> Pretty.writeln;

 (*** 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 declarations_of thy name = the_locale thy name |>

   #decls |> pairself (map fst);

 fun dependencies_of thy name = the_locale thy name |>

   #dependencies |> map fst;

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

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

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

 local

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

 structure Identifiers = GenericDataFun

 (

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

   val empty = Ready [];

   val extend = I;

   fun merge _ = ToDo;

 );

 fun finish thy (ToDo (i1, i2)) = merge (ident_eq 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 (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;

     in

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

       then (deps, marked)

       else

         let

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

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

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

         in

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

         end

     end;

 in

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

   let

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

       existing registrations). *)

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

     (* Filter out exisiting fragments. *)

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

       member (ident_eq thy) marked (name, instance_of thy name morph)) dependencies;

   in

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

   end;

 end;

 (* Declarations, facts and entire locale content *)

 fun activate_decls (name, morph) context =

   let

     val thy = Context.theory_of context;

     val {decls = (typ_decls, term_decls), ...} = the_locale thy name;

   in

     context

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

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

   end;

 fun activate_notes activ_elem transfer thy (name, morph) input =

   let

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

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

       let

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

       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 thy;

   in

     roundup thy activate (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;

     val context' = roundup thy activate_decls dep (get_idents context, context) |-> put_idents;

   in context' end);

 fun activate_facts dep context =

   let

     val thy = Context.theory_of context;

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

   in roundup thy activate 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 thy)) |-> put_idents |> Context.proof_of;

 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;

 (*** Registrations: interpretations in theories ***)

 structure Registrations = TheoryDataFun

 (

   type T = ((string * (morphism * morphism)) * stamp) list;

     (* FIXME mixins need to be stamped *)

     (* registrations, in reverse order of declaration *)

   val empty = [];

   val extend = I;

   val copy = I;

   fun merge _ data : T = Library.merge (eq_snd op =) data;

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

 );

 val get_registrations =

   Registrations.get #> map (#1 #> apsnd op $>);

 fun add_registration (name, (base_morph, export)) thy =

   roundup thy (fn (name', morph') => Registrations.map (cons ((name', (morph', export)), stamp ())))

     (name, base_morph) (get_idents (Context.Theory thy), thy) |> snd;

     (* FIXME |-> put_global_idents ?*)

 fun amend_registration morph (name, base_morph) thy =

   let

     val regs = map #1 (Registrations.get thy);

     val base = instance_of thy name base_morph;

     fun match (name', (morph', _)) =

       name = name' andalso eq_list (op aconv) (base, instance_of thy name' morph');

     val i = find_index match (rev regs);

     val _ =

       if i = ~1 then error ("No registration of locale " ^

         quote (extern thy name) ^ " and parameter instantiation " ^

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

       else ();

   in

     Registrations.map (nth_map (length regs - 1 - i)

       (fn ((name, (base, export)), stamp) => ((name, (base $> morph, export)), stamp))) thy

   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.theory (

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

         #>

       (* Registrations *)

       (fn thy => fold_rev (fn (name, 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)

         (get_registrations thy |> filter (fn (name, _) => name = loc)) thy))

   in ctxt'' end;

 (* Declarations *)

 local

 fun decl_attrib decl phi = Thm.declaration_attribute (K (decl phi));

 fun add_decls add loc decl =

   ProofContext.theory ((change_locale loc o apfst o apfst) (add (decl, stamp ()))) #>

   add_thmss loc Thm.internalK

     [((Binding.empty, [Attrib.internal (decl_attrib decl)]), [([Drule.dummy_thm], [])])];

 in

 val add_type_syntax = add_decls (apfst o cons);

 val add_term_syntax = add_decls (apsnd o cons);

 val add_declaration = add_decls (K I);

 end;

 (* Dependencies *)

 fun add_dependency loc dep = (change_locale loc o apsnd) (cons (dep, stamp ()));

 (*** Reasoning about locales ***)

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

 structure Thms = GenericDataFun

 (

   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 intro_locales_tac eager ctxt =

   Method.intros_tac

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

 val _ = Context.>> (Context.map_theory

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

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

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

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

 end;