src/Pure/Isar/locale.ML

Proper inheritance of mixins for activated facts and locale dependencies.

(*  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

  (* 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

  (* 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 and dependencies *)
  val add_registration: string * morphism -> (morphism * bool) option ->
    morphism -> theory -> theory
  val amend_registration: string * morphism -> morphism * bool ->
    morphism -> theory -> theory
  val add_dependency: string -> string * morphism -> morphism -> theory -> theory

  (* Diagnostic *)
  val print_locales: theory -> unit
  val print_locale: theory -> bool -> xstring -> unit
  val print_registrations: theory -> string -> 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 * serial) list * (declaration * serial) list,
    (* type and term syntax declarations *)
  notes: ((string * (Attrib.binding * (thm list * Attrib.src list) list) list) * serial) list,
    (* theorem declarations *)
  dependencies: ((string * morphism) * serial) 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 = 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 decls notes dependencies thy =
  thy |> Locales.map (Name_Space.define true (Sign.naming_of thy)
    (binding,
      mk_locale ((parameters, spec, intros, axioms),
        ((pairself (map (fn decl => (decl, serial ()))) decls, map (fn n => (n, serial ())) notes),
          map (fn d => (d, serial ())) 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 (Name_Space.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);
(* FIXME: this is ident_le, smaller term is more general *)

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_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 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_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) 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_eq thy) marked (name, instance_of thy name (morph $> export))) 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 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_decls Morphism.identity dep (get_idents context, context) |-> put_idents 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 Morphism.identity 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 = Theory_Data
(
  type T = ((string * (morphism * morphism)) * serial) list *
    (* registrations, in reverse order of declaration;
       serial points to mixin list *)
    (serial * ((morphism * bool) * serial) list) list;
    (* alist 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 = ([], []);
  val extend = I;
  fun merge ((r1, m1), (r2, m2)) : T =
    (Library.merge (eq_snd op =) (r1, r2),
      AList.join (op =) (K (Library.merge (eq_snd op =))) (m1, m2));
    (* FIXME consolidate with dependencies, consider one data slot only *)
);


(* Primitive operations *)

fun add_reg export (dep, morph) =
  Registrations.map (apfst (cons ((dep, (morph, export)), serial ())));

fun add_mixin serial' mixin =
  (* registration to be amended identified by its serial id *)
  Registrations.map (apsnd (AList.map_default (op =) (serial', []) (cons (mixin, serial ()))));

fun get_mixins thy (name, morph) =
  let
    val (regs, mixins) = Registrations.get thy;
  in
    case find_first (fn ((name', (morph', export')), _) => ident_eq thy
      ((name', instance_of thy name' (morph' $> export')), (name, instance_of thy name morph))) (rev regs) of
      NONE => []
    | SOME (_, serial) => the_default [] (AList.lookup (op =) mixins serial)
  end;

fun collect_mixins thy (name, morph) =
  roundup thy (fn dep => fn mixins =>
    merge (eq_snd op =) (mixins, get_mixins thy dep)) Morphism.identity (name, morph) ([], [])
  |> snd |> filter (snd o fst);  (* only inheritable mixins *)
  (* FIXME refactor usage *)

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

fun reg_morph mixins ((name, (base, export)), serial) =
  let val mix = the_default [] (AList.lookup (op =) mixins serial) |> compose_mixins;
  in (name, base $> mix $> export) end;

fun these_registrations thy name = Registrations.get thy
  |>> filter (curry (op =) name o fst o fst)
  (* with inherited mixins *)
  |-> (fn regs => fn _ => map (fn ((name, (base, export)) ,_) =>
    (name, base $> (collect_mixins thy (name, base $> export) |> compose_mixins) $> export)) regs);

fun all_registrations thy = Registrations.get thy
  |-> (fn regs => fn mixins => map (reg_morph mixins) regs);
  (* without inherited mixins *)

fun activate_notes' activ_elem transfer thy export (name, morph) input =
  let
    val {notes, ...} = the_locale thy name;
    fun activate ((kind, facts), _) input =
      let
        val mixin = collect_mixins thy (name, morph $> export) |> compose_mixins;
        val facts' = facts |> Element.facts_map (Element.morph_ctxt (transfer input $> morph $> mixin $> export))
      in activ_elem (Notes (kind, facts')) input end;
  in
    fold_rev activate notes input
  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) thy export;
  in roundup thy activate export dep (get_idents context, context) |-> put_idents end;


(* Diagnostic *)

fun print_registrations thy raw_name =
  let
    val name = intern thy raw_name;
    val name' = extern thy name;
    val ctxt = ProofContext.init 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));
    fun prt_reg (name, morph) =
      let
        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;
  in
    (case these_registrations thy name of
        [] => Pretty.str ("no interpretations")
      | regs => Pretty.big_list "interpretations:" (map prt_reg (rev regs)))
    |> Pretty.writeln
  end;


(* Add and extend registrations *)

fun amend_registration (name, morph) mixin export thy =
  let
    val regs = Registrations.get thy |> fst;
    val base = instance_of thy name (morph $> export);
    fun match ((name', (morph', export')), _) =
      name = name' andalso eq_list (op aconv) (base, instance_of thy name' (morph' $> export'));
  in
    case find_first match (rev regs) 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 thy
  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 thy =
  let
    val base = instance_of thy name base_morph;
  in
    if member (ident_eq thy) (get_idents (Context.Theory thy)) (name, base)
    then thy
    else
      (get_idents (Context.Theory thy), thy)
      (* add new registrations with inherited mixins *)
      |> roundup thy (add_reg export) export (name, base_morph)
      |> snd
      (* add mixin *)
      |> (case mixin of NONE => I
           | SOME mixin => amend_registration (name, base_morph) mixin export)
      (* activate import hierarchy as far as not already active *)
      |> Context.theory_map (activate_facts' export (name, base_morph))
  end;


(*** Dependencies ***)

fun add_reg_activate_facts export (dep, morph) thy =
  (get_idents (Context.Theory thy), thy)
  |> roundup thy (add_reg export) export (dep, morph)
  |> snd
  |> Context.theory_map (activate_facts' export (dep, morph));

fun add_dependency loc (dep, morph) export thy =
  thy
  |> (change_locale loc o apsnd) (cons ((dep, morph $> export), serial ()))
  |> (fn thy => fold_rev (add_reg_activate_facts export)
      (all_registrations thy) thy);


(*** 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', 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)
        (these_registrations thy 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, serial ()))) #>
  add_thmss loc ""
    [((Binding.conceal 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;


(*** 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"));

end;