src/Pure/Isar/local_theory.ML

turned into abstract wrapper module, cf. theory_target.ML;
simplified interfaces;

(*  Title:      Pure/Isar/local_theory.ML
    ID:         $Id$
    Author:     Makarius

Local theory operations, with abstract target context.
*)

type local_theory = Proof.context;

signature LOCAL_THEORY =
sig
  type operations
  val target_of: local_theory -> Proof.context
  val init: string option -> operations -> Proof.context -> local_theory
  val reinit: local_theory -> local_theory
  val theory: (theory -> theory) -> local_theory -> local_theory
  val theory_result: (theory -> 'a * theory) -> local_theory -> 'a * local_theory
  val target: (Proof.context -> Proof.context) -> local_theory -> local_theory
  val target_result: (Proof.context -> 'a * Proof.context) -> local_theory -> 'a * local_theory
  val pretty: local_theory -> Pretty.T
  val consts: (string * typ -> bool) ->
    ((bstring * typ) * mixfix) list -> local_theory -> (term * thm) list * local_theory
  val axioms: ((bstring * Attrib.src list) * term list) list -> local_theory ->
    (bstring * thm list) list * local_theory
  val defs: ((bstring * mixfix) * ((bstring * Attrib.src list) * term)) list ->
    local_theory -> (term * (bstring * thm)) list * local_theory
  val notes: ((bstring * Attrib.src list) * (thm list * Attrib.src list) list) list ->
    local_theory -> (bstring * thm list) list * local_theory
  val term_syntax: (Context.generic -> Context.generic) -> local_theory -> local_theory
  val declaration: (Context.generic -> Context.generic) -> local_theory -> local_theory
  val def: (bstring * mixfix) * ((bstring * Attrib.src list) * term) ->
    local_theory -> (term * (bstring * thm)) * local_theory
  val note: (bstring * Attrib.src list) * thm list ->
    local_theory -> (bstring * thm list) * Proof.context
  val const_syntax: Syntax.mode -> (string * mixfix) list -> local_theory -> local_theory
  val abbrevs: Syntax.mode -> ((bstring * mixfix) * term) list -> local_theory -> local_theory
end;

structure LocalTheory: LOCAL_THEORY =
struct

(** local theory data **)

(* type lthy *)

type operations =
 {pretty: local_theory -> Pretty.T,
  consts: (string * typ -> bool) -> ((bstring * typ) * mixfix) list -> local_theory ->
    (term * thm) list * local_theory,
  axioms: ((bstring * Attrib.src list) * term list) list -> local_theory ->
    (bstring * thm list) list * local_theory,
  defs: ((bstring * mixfix) * ((bstring * Attrib.src list) * term)) list -> local_theory ->
    (term * (bstring * thm)) list * local_theory,
  notes: ((bstring * Attrib.src list) * (thm list * Attrib.src list) list) list -> local_theory ->
    (bstring * thm list) list * local_theory,
  term_syntax: (Context.generic -> Context.generic) -> local_theory -> local_theory,
  declaration: (Context.generic -> Context.generic) -> local_theory -> local_theory};

datatype lthy = LThy of
 {theory_prefix: string option,
  operations: operations,
  target: Proof.context};

fun make_lthy (theory_prefix, operations, target) =
  LThy {theory_prefix = theory_prefix, operations = operations, target = target};


(* context data *)

structure Data = ProofDataFun
(
  val name = "Pure/local_theory";
  type T = lthy option;
  fun init _ = NONE;
  fun print _ _ = ();
);
val _ = Context.add_setup Data.init;

fun get_lthy lthy =
  (case Data.get lthy of
    NONE => error "No local theory context"
  | SOME (LThy data) => data);

fun map_lthy f lthy =
  let val {theory_prefix, operations, target} = get_lthy lthy
  in Data.put (SOME (make_lthy (f (theory_prefix, operations, target)))) lthy end;

val target_of = #target o get_lthy;

fun map_target f = map_lthy (fn (theory_prefix, operations, target) =>
  (theory_prefix, operations, f target));


(* init *)

fun init theory_prefix operations target = target |> Data.map
  (fn NONE => SOME (make_lthy (theory_prefix, operations, target))
    | SOME _ => error "Local theory already initialized");

fun reinit lthy =
  let val {theory_prefix, operations, target} = get_lthy lthy
  in init theory_prefix operations target end;


(* substructure mappings *)

fun theory_result f lthy =
  (case #theory_prefix (get_lthy lthy) of
    NONE => error "Cannot change background theory"
  | SOME prefix =>
      let
        val thy = ProofContext.theory_of lthy;
        val (res, thy') = thy
          |> Sign.sticky_prefix prefix
          |> Sign.qualified_names
          |> f
          ||> Sign.restore_naming thy;
        val lthy' = lthy
          |> map_target (ProofContext.transfer thy')
          |> ProofContext.transfer thy';
      in (res, lthy') end);

fun theory f = #2 o theory_result (f #> pair ());

fun target_result f lthy =
  let
    val (res, ctxt') = f (#target (get_lthy lthy));
    val thy' = ProofContext.theory_of ctxt';
    val lthy' = lthy
      |> map_target (K ctxt')
      |> ProofContext.transfer thy';
  in (res, lthy') end;

fun target f = #2 o target_result (f #> pair ());


(* primitive operations *)

fun operation f lthy = f (#operations (get_lthy lthy)) lthy;
fun operation1 f x = operation (fn ops => f ops x);
fun operation2 f x y = operation (fn ops => f ops x y);

val pretty = operation #pretty;
val consts = operation2 #consts;
val axioms = operation1 #axioms;
val defs = operation1 #defs;
val notes = operation1 #notes;
val term_syntax = operation1 #term_syntax;
val declaration = operation1 #declaration;


(* derived operations *)

fun def arg lthy = lthy |> defs [arg] |>> hd;

fun note (a, ths) lthy = lthy |> notes [(a, [(ths, [])])] |>> hd;

fun const_syntax mode args =
  term_syntax
    (Context.mapping (Sign.add_const_syntax mode args) (ProofContext.add_const_syntax mode args));

fun abbrevs mode args =
  term_syntax (Context.mapping (Sign.add_abbrevs mode args) (ProofContext.add_abbrevs mode args));

end;