(*  Title:      Pure/Isar/theory_target.ML

     ID:         $Id$

     Author:     Makarius

 Common theory/locale/class targets.

 *)

 signature THEORY_TARGET =

 sig

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

   val begin: string -> Proof.context -> local_theory

   val init: string option -> theory -> local_theory

   val init_cmd: xstring option -> theory -> local_theory

 end;

 structure TheoryTarget: THEORY_TARGET =

 struct

 (* context data *)

 datatype target = Target of {target: string, is_locale: bool, is_class: bool};

 fun make_target target is_locale is_class =

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

 structure Data = ProofDataFun

 (

   type T = target;

   fun init _ = make_target "" false false;

 );

 val peek = (fn Target args => args) o Data.get;

 (* pretty *)

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

   let

     val thy = ProofContext.theory_of ctxt;

     val target_name = (if is_class then "class " else "locale ") ^ Locale.extern thy target;

     val fixes = map (fn (x, T) => (x, SOME T, NoSyn)) (#1 (ProofContext.inferred_fixes ctxt));

     val assumes = map (fn A => (("", []), [(A, [])])) (map Thm.term_of (Assumption.assms_of ctxt));

     val elems =

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

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

   in

     Pretty.block [Pretty.str "theory", Pretty.brk 1, Pretty.str (Context.theory_name thy)] ::

      (if target = "" then []

       else if null elems then [Pretty.str target_name]

       else [Pretty.big_list (target_name ^ " =")

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

   end;

 (* target declarations *)

 fun target_decl add (Target {target, ...}) d lthy =

   let

     val d' = Morphism.transform (LocalTheory.target_morphism lthy) d;

     val d0 = Morphism.form d';

   in

     if target = "" then

       lthy

       |> LocalTheory.theory (Context.theory_map d0)

       |> LocalTheory.target (Context.proof_map d0)

     else

       lthy

       |> LocalTheory.target (add target d')

   end;

 val type_syntax = target_decl Locale.add_type_syntax;

 val term_syntax = target_decl Locale.add_term_syntax;

 val declaration = target_decl Locale.add_declaration;

 fun target_naming (Target {target, ...}) lthy =

   (if target = "" then Sign.naming_of (ProofContext.theory_of lthy)

    else ProofContext.naming_of (LocalTheory.target_of lthy))

   |> NameSpace.qualified_names;

 fun class_target (Target {target, ...}) f =

   LocalTheory.raw_theory f #>

   LocalTheory.target (Class.refresh_syntax target);

 (* notes *)

 fun import_export_proof ctxt (name, raw_th) =

   let

     val thy = ProofContext.theory_of ctxt;

     val thy_ctxt = ProofContext.init thy;

     val certT = Thm.ctyp_of thy;

     val cert = Thm.cterm_of thy;

     (*export assumes/defines*)

     val th = Goal.norm_result raw_th;

     val (defs, th') = LocalDefs.export ctxt thy_ctxt th;

     val concl_conv = MetaSimplifier.rewrite true defs (Thm.cprop_of th);

     val assms = map (MetaSimplifier.rewrite_rule defs o Thm.assume) (Assumption.assms_of ctxt);

     val nprems = Thm.nprems_of th' - Thm.nprems_of th;

     (*export fixes*)

     val tfrees = map TFree (Thm.fold_terms Term.add_tfrees th' []);

     val frees = map Free (Thm.fold_terms Term.add_frees th' []);

     val (th'' :: vs) = (th' :: map (Drule.mk_term o cert) (map Logic.mk_type tfrees @ frees))

       |> Variable.export ctxt thy_ctxt

       |> Drule.zero_var_indexes_list;

     (*thm definition*)

     val result = th''

       |> PureThy.name_thm true true ""

       |> Goal.close_result

       |> fold PureThy.tag_rule (ContextPosition.properties_of ctxt)

       |> PureThy.name_thm true true name;

     (*import fixes*)

     val (tvars, vars) =

       chop (length tfrees) (map (Thm.term_of o Drule.dest_term) vs)

       |>> map Logic.dest_type;

     val instT = map_filter (fn (TVar v, T) => SOME (v, T) | _ => NONE) (tvars ~~ tfrees);

     val inst = filter (is_Var o fst) (vars ~~ frees);

     val cinstT = map (pairself certT o apfst TVar) instT;

     val cinst = map (pairself (cert o Term.map_types (TermSubst.instantiateT instT))) inst;

     val result' = Thm.instantiate (cinstT, cinst) result;

     (*import assumes/defines*)

     val assm_tac = FIRST' (map (fn assm => Tactic.compose_tac (false, assm, 0)) assms);

     val result'' =

       (case SINGLE (Seq.INTERVAL assm_tac 1 nprems) result' of

         NONE => raise THM ("Failed to re-import result", 0, [result'])

       | SOME res => LocalDefs.trans_props ctxt [res, Thm.symmetric concl_conv])

       |> Goal.norm_result

       |> PureThy.name_thm false false name;

   in (result'', result) end;

 fun notes (Target {target, is_locale, ...}) kind facts lthy =

   let

     val thy = ProofContext.theory_of lthy;

     val full = LocalTheory.full_name lthy;

     val facts' = facts

       |> map (fn (a, bs) => (a, PureThy.burrow_fact (PureThy.name_multi (full (fst a))) bs))

       |> PureThy.map_facts (import_export_proof lthy);

     val local_facts = PureThy.map_facts #1 facts'

       |> Attrib.map_facts (Attrib.attribute_i thy);

     val target_facts = PureThy.map_facts #1 facts'

       |> is_locale ? Element.facts_map (Element.morph_ctxt (LocalTheory.target_morphism lthy));

     val global_facts = PureThy.map_facts #2 facts'

       |> Attrib.map_facts (if is_locale then K I else Attrib.attribute_i thy);

   in

     lthy |> LocalTheory.theory

       (Sign.qualified_names

         #> PureThy.note_thmss_i kind global_facts #> snd

         #> Sign.restore_naming thy)

     |> is_locale ? LocalTheory.target (Locale.add_thmss target kind target_facts)

     |> ProofContext.qualified_names

     |> ProofContext.note_thmss_i kind local_facts

     ||> ProofContext.restore_naming lthy

   end;

 (* declare_const *)

 fun fork_mixfix (Target {is_locale, is_class, ...}) mx =

   if not is_locale then (NoSyn, NoSyn, mx)

   else if not is_class then (NoSyn, mx, NoSyn)

   else (mx, NoSyn, NoSyn);

 fun locale_const (prmode as (mode, _)) pos ((c, mx), rhs) phi =

   let

     val c' = Morphism.name phi c;

     val rhs' = Morphism.term phi rhs;

     val legacy_arg = (c', Term.close_schematic_term (Logic.legacy_varify rhs'));

     val arg = (c', Term.close_schematic_term rhs');

   in

     Context.mapping_result

       (Sign.add_abbrev PrintMode.internal pos legacy_arg)

       (ProofContext.add_abbrev PrintMode.internal pos arg)

     #-> (fn (lhs' as Const (d, _), _) =>

         Type.similar_types (rhs, rhs') ?

           (Context.mapping (Sign.revert_abbrev mode d) (ProofContext.revert_abbrev mode d) #>

            Morphism.form (ProofContext.target_notation true prmode [(lhs', mx)])))

   end;

 fun declare_const (ta as Target {target, is_locale, is_class}) depends ((c, T), mx) lthy =

   let

     val pos = ContextPosition.properties_of lthy;

     val xs = filter depends (#1 (ProofContext.inferred_fixes (LocalTheory.target_of lthy)));

     val U = map #2 xs ---> T;

     val (mx1, mx2, mx3) = fork_mixfix ta mx;

     val (const, lthy') = lthy |> LocalTheory.theory_result (Sign.declare_const pos (c, U, mx3));

     val t = Term.list_comb (const, map Free xs);

   in

     lthy'

     |> is_locale ? term_syntax ta (locale_const Syntax.mode_default pos ((c, mx2), t))

     |> is_class ? class_target ta (Class.add_logical_const target pos ((c, mx1), t))

     |> LocalDefs.add_def ((c, NoSyn), t)

   end;

 (* abbrev *)

 fun abbrev (ta as Target {target, is_locale, is_class}) prmode ((c, mx), t) lthy =

   let

     val pos = ContextPosition.properties_of lthy;

     val thy_ctxt = ProofContext.init (ProofContext.theory_of lthy);

     val target_ctxt = LocalTheory.target_of lthy;

     val (mx1, mx2, mx3) = fork_mixfix ta mx;

     val t' = Assumption.export_term lthy target_ctxt t;

     val xs = map Free (rev (Variable.add_fixed target_ctxt t' []));

     val u = fold_rev lambda xs t';

     val global_rhs =

       singleton (Variable.export_terms (Variable.declare_term u target_ctxt) thy_ctxt) u;

     val class_t = Morphism.term (LocalTheory.target_morphism lthy) t;

   in

     lthy |>

      (if is_locale then

         LocalTheory.theory_result (Sign.add_abbrev PrintMode.internal pos (c, global_rhs))

         #-> (fn (lhs, _) =>

           let val lhs' = Term.list_comb (Logic.unvarify lhs, xs) in

             term_syntax ta (locale_const prmode pos ((c, mx2), lhs')) #>

             is_class ?

               class_target ta (Class.add_syntactic_const target prmode pos ((c, mx1), class_t))

           end)

       else

         LocalTheory.theory

           (Sign.add_abbrev (#1 prmode) pos (c, global_rhs) #-> (fn (lhs, _) =>

            Sign.notation true prmode [(lhs, mx3)])))

     |> ProofContext.add_abbrev PrintMode.internal pos (c, t) |> snd

     |> LocalDefs.fixed_abbrev ((c, NoSyn), t)

   end;

 (* define *)

 fun define (ta as Target {target, is_locale, is_class})

     kind ((c, mx), ((name, atts), rhs)) lthy =

   let

     val thy = ProofContext.theory_of lthy;

     val thy_ctxt = ProofContext.init thy;

     val name' = Thm.def_name_optional c name;

     val (rhs', rhs_conv) =

       LocalDefs.export_cterm lthy thy_ctxt (Thm.cterm_of thy rhs) |>> Thm.term_of;

     val xs = Variable.add_fixed (LocalTheory.target_of lthy) rhs' [];

     val T = Term.fastype_of rhs;

     (*const*)

     val ((lhs, local_def), lthy2) = lthy |> declare_const ta (member (op =) xs) ((c, T), mx);

     val (_, lhs') = Logic.dest_equals (Thm.prop_of local_def);

     (*def*)

     val (global_def, lthy3) = lthy2

       |> LocalTheory.theory_result (Thm.add_def false (name', Logic.mk_equals (lhs', rhs')));

     val def = LocalDefs.trans_terms lthy3

       [(*c == global.c xs*)     local_def,

        (*global.c xs == rhs'*)  global_def,

        (*rhs' == rhs*)          Thm.symmetric rhs_conv];

     (*note*)

     val ([(res_name, [res])], lthy4) = lthy3

       |> notes ta kind [((name', atts), [([def], [])])];

   in ((lhs, (res_name, res)), lthy4) end;

 (* axioms *)

 fun axioms ta kind (vars, specs) lthy =

   let

     val thy_ctxt = ProofContext.init (ProofContext.theory_of lthy);

     val expanded_props = map (Assumption.export_term lthy thy_ctxt) (maps snd specs);

     val xs = fold Term.add_frees expanded_props [];

     (*consts*)

     val (consts, lthy') = fold_map (declare_const ta (member (op =) xs)) vars lthy;

     val global_consts = map (Term.dest_Const o Term.head_of o Thm.term_of o Thm.rhs_of o #2) consts;

     (*axioms*)

     val hyps = map Thm.term_of (Assumption.assms_of lthy');

     fun axiom ((name, atts), props) thy = thy

       |> fold_map (Thm.add_axiom hyps) (PureThy.name_multi name props)

       |-> (fn ths => pair ((name, atts), [(ths, [])]));

   in

     lthy'

     |> fold Variable.declare_term expanded_props

     |> LocalTheory.theory (fold (fn c => Theory.add_deps "" c []) global_consts)

     |> LocalTheory.theory_result (fold_map axiom specs)

     |-> notes ta kind

     |>> pair (map #1 consts)

   end;

 (* init and exit *)

 fun begin target ctxt =

   let

     val thy = ProofContext.theory_of ctxt;

     val is_locale = target <> "";

     val is_class = Class.is_class thy target;

     val ta = Target {target = target, is_locale = is_locale, is_class = is_class};

   in

     ctxt

     |> Data.put ta

     |> is_class ? Class.init target

     |> LocalTheory.init (NameSpace.base target)

      {pretty = pretty ta,

       axioms = axioms ta,

       abbrev = abbrev ta,

       define = define ta,

       notes = notes ta,

       type_syntax = type_syntax ta,

       term_syntax = term_syntax ta,

       declaration = declaration ta,

       target_naming = target_naming ta,

       reinit = fn _ =>

         begin target o (if is_locale then Locale.init target else ProofContext.init),

       exit = LocalTheory.target_of}

   end;

 fun init NONE thy = begin "" (ProofContext.init thy)

   | init (SOME target) thy = begin target (Locale.init target thy);

 fun init_cmd (SOME "-") thy = init NONE thy

   | init_cmd target thy = init (Option.map (Locale.intern thy) target) thy;

 end;