(*  Title:      Pure/Isar/named_target.ML

     Author:     Makarius

     Author:     Florian Haftmann, TU Muenchen

 Targets for theory, locale, class -- at the bottom the nested structure.

 *)

 signature NAMED_TARGET =

 sig

   val peek: local_theory -> {target: string, is_locale: bool, is_class: bool} option

   val init: (local_theory -> local_theory) -> string -> theory -> local_theory

   val theory_init: theory -> local_theory

   val reinit: local_theory -> local_theory -> local_theory

   val context_cmd: xstring * Position.T -> theory -> local_theory

 end;

 structure Named_Target: NAMED_TARGET =

 struct

 (* context data *)

 datatype target =

   Target of {target: string, is_locale: bool, is_class: bool,

     before_exit: local_theory -> local_theory};

 fun make_target target is_locale is_class before_exit =

   Target {target = target, is_locale = is_locale, is_class = is_class,

     before_exit = before_exit};

 fun named_target _ "" before_exit = make_target "" false false before_exit

   | named_target thy locale before_exit =

       if Locale.defined thy locale

       then make_target locale true (Class.is_class thy locale) before_exit

       else error ("No such locale: " ^ quote locale);

 structure Data = Proof_Data

 (

   type T = target option;

   fun init _ = NONE;

 );

 val peek =

   Data.get #> Option.map (fn Target {target, is_locale, is_class, ...} =>

     {target = target, is_locale = is_locale, is_class = is_class});

 (* consts in locale *)

 fun locale_const (Target {target, is_class, ...}) prmode ((b, mx), rhs) =

   Generic_Target.locale_declaration target true (fn phi =>

     let

       val b' = Morphism.binding phi b;

       val rhs' = Morphism.term phi rhs;

       val same_shape = Term.aconv_untyped (rhs, rhs');

       (* FIXME workaround based on educated guess *)

       val prefix' = Binding.prefix_of b';

       val is_canonical_class = is_class andalso

         (Binding.eq_name (b, b')

           andalso not (null prefix')

           andalso List.last prefix' = (Class.class_prefix target, false)

         orelse same_shape);

     in

       not is_canonical_class ?

         Generic_Target.generic_const same_shape prmode ((b', mx), Term.close_schematic_term rhs')

     end) #>

   (fn lthy => lthy |> Generic_Target.const_declaration

     (fn level => level <> 0 andalso level <> Local_Theory.level lthy) prmode ((b, mx), rhs));

 (* define *)

 fun locale_foundation ta (((b, U), mx), (b_def, rhs)) (type_params, term_params) =

   Generic_Target.background_foundation (((b, U), NoSyn), (b_def, rhs)) (type_params, term_params)

   #-> (fn (lhs, def) => locale_const ta Syntax.mode_default ((b, mx), lhs)

     #> pair (lhs, def));

 fun class_foundation (ta as Target {target, ...})

     (((b, U), mx), (b_def, rhs)) (type_params, term_params) =

   Generic_Target.background_foundation (((b, U), NoSyn), (b_def, rhs)) (type_params, term_params)

   #-> (fn (lhs, def) => locale_const ta Syntax.mode_default ((b, NoSyn), lhs)

     #> Class.const target ((b, mx), (type_params, lhs))

     #> pair (lhs, def));

 fun target_foundation (ta as Target {is_locale, is_class, ...}) =

   if is_class then class_foundation ta

   else if is_locale then locale_foundation ta

   else Generic_Target.theory_foundation;

 (* notes *)

 fun target_notes (Target {target, is_locale, ...}) =

   if is_locale then Generic_Target.locale_notes target

   else Generic_Target.theory_notes;

 (* abbrev *)

 fun locale_abbrev ta prmode ((b, mx), t) xs =

   Local_Theory.background_theory_result

     (Sign.add_abbrev Print_Mode.internal (b, t)) #->

       (fn (lhs, _) =>

         locale_const ta prmode ((b, mx), Term.list_comb (Logic.unvarify_global lhs, xs)));

 fun target_abbrev (ta as Target {target, is_locale, is_class, ...}) prmode (b, mx) (t, t') xs lthy =

   if is_locale then

     lthy

     |> locale_abbrev ta prmode ((b, if is_class then NoSyn else mx), t) xs

     |> is_class ? Class.abbrev target prmode ((b, mx), t')

   else lthy |> Generic_Target.theory_abbrev prmode (b, mx) (t, t') xs;

 (* declaration *)

 fun target_declaration (Target {target, ...}) {syntax, pervasive} decl lthy =

   if target = "" then Generic_Target.theory_declaration decl lthy

   else

     lthy

     |> pervasive ? Generic_Target.background_declaration decl

     |> Generic_Target.locale_declaration target syntax decl

     |> (fn lthy' => lthy' |> Generic_Target.standard_declaration (fn level => level <> 0) decl);

 (* pretty *)

 fun pretty (Target {target, is_locale, is_class, ...}) ctxt =

   let

     val thy = Proof_Context.theory_of ctxt;

     val target_name =

       [Pretty.command (if is_class then "class" else "locale"),

         Pretty.str (" " ^ Locale.extern thy target)];

     val fixes =

       map (fn (x, T) => (Binding.name x, SOME T, NoSyn))

         (#1 (Proof_Context.inferred_fixes ctxt));

     val assumes =

       map (fn A => (Attrib.empty_binding, [(Thm.term_of A, [])]))

         (Assumption.all_assms_of ctxt);

     val elems =

       (if null fixes then [] else [Element.Fixes fixes]) @

       (if null assumes then [] else [Element.Assumes assumes]);

     val body_elems =

       if not is_locale then []

       else if null elems then [Pretty.block target_name]

       else [Pretty.block (Pretty.fbreaks (Pretty.block (target_name @ [Pretty.str " ="]) ::

         map (Pretty.chunks o Element.pretty_ctxt ctxt) elems))];

   in

     Pretty.block [Pretty.command "theory", Pretty.brk 1,

       Pretty.str (Context.theory_name (Proof_Context.theory_of ctxt))] :: body_elems

   end;

 (* init *)

 fun init_context (Target {target, is_locale, is_class, ...}) =

   if not is_locale then Proof_Context.init_global

   else if not is_class then Locale.init target

   else Class.init target;

 fun init before_exit target thy =

   let

     val ta = named_target thy target before_exit;

     val naming = Sign.naming_of thy

       |> Name_Space.mandatory_path (Long_Name.base_name target);

   in

     thy

     |> init_context ta

     |> Data.put (SOME ta)

     |> Local_Theory.init naming

        {define = Generic_Target.define (target_foundation ta),

         notes = Generic_Target.notes (target_notes ta),

         abbrev = Generic_Target.abbrev (target_abbrev ta),

         declaration = target_declaration ta,

         pretty = pretty ta,

         exit = Local_Theory.target_of o before_exit}

   end;

 val theory_init = init I "";

 val reinit =

   Local_Theory.assert_bottom true #> Data.get #> the #>

   (fn Target {target, before_exit, ...} => Local_Theory.exit_global #> init before_exit target);

 fun context_cmd ("-", _) thy = theory_init thy

   | context_cmd target thy = init I (Locale.check thy target) thy;

 end;