(*  Title:      Pure/ML/ml_context.ML

    Author:     Makarius

ML context and antiquotations.

*)

signature BASIC_ML_CONTEXT =

sig

  val bind_thm: string * thm -> unit

  val bind_thms: string * thm list -> unit

  val thm: xstring -> thm

  val thms: xstring -> thm list

end

signature ML_CONTEXT =

sig

  include BASIC_ML_CONTEXT

  val the_generic_context: unit -> Context.generic

  val the_global_context: unit -> theory

  val the_local_context: unit -> Proof.context

  val exec: (unit -> unit) -> Context.generic -> Context.generic

  val stored_thms: thm list Unsynchronized.ref

  val ml_store_thm: string * thm -> unit

  val ml_store_thms: string * thm list -> unit

  type antiq = Proof.context -> (Proof.context -> string * string) * Proof.context

  val add_antiq: string -> (Position.T -> antiq context_parser) -> unit

  val trace: bool Unsynchronized.ref

  val eval_antiquotes: ML_Lex.token Antiquote.antiquote list * Position.T ->

    Context.generic option -> (ML_Lex.token list * ML_Lex.token list) * Context.generic option

  val eval: bool -> Position.T -> ML_Lex.token Antiquote.antiquote list -> unit

  val eval_text: bool -> Position.T -> Symbol_Pos.text -> unit

  val eval_file: Path.T -> unit

  val eval_in: Proof.context option -> bool -> Position.T ->

    ML_Lex.token Antiquote.antiquote list -> unit

  val eval_text_in: Proof.context option -> bool -> Position.T -> Symbol_Pos.text -> unit

  val expression: Position.T -> string -> string -> ML_Lex.token Antiquote.antiquote list ->

    Context.generic -> Context.generic

  val evaluate:

    Proof.context -> bool -> string * (unit -> 'a) option Unsynchronized.ref -> string -> 'a

end

structure ML_Context: ML_CONTEXT =

struct

(** implicit ML context **)

val the_generic_context = Context.the_thread_data;

val the_global_context = Context.theory_of o the_generic_context;

val the_local_context = Context.proof_of o the_generic_context;

fun exec (e: unit -> unit) context =

  (case Context.setmp_thread_data (SOME context) (fn () => (e (); Context.thread_data ())) () of

    SOME context' => context'

  | NONE => error "Missing context after execution");

(* theorem bindings *)

val stored_thms: thm list Unsynchronized.ref = Unsynchronized.ref [];  (* FIXME via context!? *)

fun ml_store sel (name, ths) =

  let

    val ths' = Context.>>> (Context.map_theory_result

      (PureThy.store_thms (Binding.name name, ths)));

    val _ =

      if name = "" then ()

      else if not (ML_Syntax.is_identifier name) then

        error ("Cannot bind theorem(s) " ^ quote name ^ " as ML value")

      else setmp_CRITICAL stored_thms ths' (fn () =>

        ML_Compiler.eval true Position.none

          (ML_Lex.tokenize ("val " ^ name ^ " = " ^ sel ^ "(! ML_Context.stored_thms);"))) ();

  in () end;

val ml_store_thms = ml_store "";

fun ml_store_thm (name, th) = ml_store "hd" (name, [th]);

fun bind_thm (name, thm) = ml_store_thm (name, Drule.export_without_context thm);

fun bind_thms (name, thms) = ml_store_thms (name, map Drule.export_without_context thms);

fun thm name = ProofContext.get_thm (the_local_context ()) name;

fun thms name = ProofContext.get_thms (the_local_context ()) name;

(** ML antiquotations **)

(* antiquotation commands *)

type antiq = Proof.context -> (Proof.context -> string * string) * Proof.context;

local

val global_parsers =

  Unsynchronized.ref (Symtab.empty: (Position.T -> antiq context_parser) Symtab.table);

in

fun add_antiq name scan = CRITICAL (fn () =>

  Unsynchronized.change global_parsers (fn tab =>

   (if not (Symtab.defined tab name) then ()

    else warning ("Redefined ML antiquotation: " ^ quote name);

    Symtab.update (name, scan) tab)));

fun antiquotation src ctxt =

  let val ((name, _), pos) = Args.dest_src src in

    (case Symtab.lookup (! global_parsers) name of

      NONE => error ("Unknown ML antiquotation command: " ^ quote name ^ Position.str_of pos)

    | SOME scan => (Position.report (Markup.ML_antiq name) pos;

        Args.context_syntax "ML antiquotation" (scan pos) src ctxt))

  end;

end;

(* parsing and evaluation *)

local

val antiq =

  Parse.!!! (Parse.position Parse.xname -- Args.parse --| Scan.ahead Parse.eof)

  >> (fn ((x, pos), y) => Args.src ((x, y), pos));

val begin_env = ML_Lex.tokenize "structure Isabelle =\nstruct\n";

val end_env = ML_Lex.tokenize "end;";

val reset_env = ML_Lex.tokenize "structure Isabelle = struct end";

in

fun eval_antiquotes (ants, pos) opt_context =

  let

    val opt_ctxt = Option.map (Context.Proof o Context.proof_of) opt_context;

    val ((ml_env, ml_body), opt_ctxt') =

      if forall Antiquote.is_text ants

      then (([], map (fn Antiquote.Text tok => tok) ants), opt_ctxt)

      else

        let

          val ctxt =

            (case opt_ctxt of

              NONE => error ("No context -- cannot expand ML antiquotations" ^ Position.str_of pos)

            | SOME ctxt => Context.proof_of ctxt);

          val lex = #1 (Keyword.get_lexicons ());

          fun no_decl _ = ([], []);

          fun expand (Antiquote.Text tok) state = (K ([], [tok]), state)

            | expand (Antiquote.Antiq (ss, range)) (scope, background) =

                let

                  val context = Stack.top scope;

                  val (f, context') =

                    antiquotation (Token.read_antiq lex antiq (ss, #1 range)) context;

                  val (decl, background') = f background;

                  val decl' = decl #> pairself (ML_Lex.tokenize #> map (ML_Lex.set_range range));

                in (decl', (Stack.map_top (K context') scope, background')) end

            | expand (Antiquote.Open _) (scope, background) =

                (no_decl, (Stack.push scope, background))

            | expand (Antiquote.Close _) (scope, background) =

                (no_decl, (Stack.pop scope, background));

          val (decls, (_, ctxt')) = fold_map expand ants (Stack.init ctxt, ctxt);

          val ml = decls |> map (fn decl => decl ctxt') |> split_list |> pairself flat;

        in (ml, SOME (Context.Proof ctxt')) end;

  in ((begin_env @ ml_env @ end_env, ml_body), opt_ctxt') end;

val trace = Unsynchronized.ref false;

fun eval verbose pos ants =

  let

    (*prepare source text*)

    val ((env, body), env_ctxt) = eval_antiquotes (ants, pos) (Context.thread_data ());

    val _ =

      if ! trace then tracing (cat_lines [ML_Lex.flatten env, ML_Lex.flatten body])

      else ();

    (*prepare static ML environment*)

    val _ = Context.setmp_thread_data env_ctxt

        (fn () => (ML_Compiler.eval false Position.none env; Context.thread_data ())) ()

      |> (fn NONE => () | SOME context' => Context.>> (ML_Env.inherit context'));

    val _ = ML_Compiler.eval verbose pos body;

    val _ = ML_Compiler.eval false Position.none reset_env;

  in () end;

end;

(* derived versions *)

fun eval_text verbose pos txt = eval verbose pos (ML_Lex.read pos txt);

fun eval_file path = eval_text true (Path.position path) (File.read path);

fun eval_in ctxt verbose pos ants =

  Context.setmp_thread_data (Option.map Context.Proof ctxt) (fn () => eval verbose pos ants) ();

fun eval_text_in ctxt verbose pos txt =

  Context.setmp_thread_data (Option.map Context.Proof ctxt) (fn () => eval_text verbose pos txt) ();

fun expression pos bind body ants =

  exec (fn () => eval false pos

    (ML_Lex.read Position.none ("Context.set_thread_data (SOME (let " ^ bind ^ " = ") @ ants @

      ML_Lex.read Position.none (" in " ^ body ^ " end (ML_Context.the_generic_context ())));")));

(* FIXME not thread-safe -- reference can be accessed directly *)

fun evaluate ctxt verbose (ref_name, r) txt = NAMED_CRITICAL "ML" (fn () =>

  let

    val ants =

      ML_Lex.read Position.none ("val _ = (" ^ ref_name ^ " := SOME (fn () => " ^ txt ^ "))");

    val _ = r := NONE;

    val _ =

      Context.setmp_thread_data (SOME (Context.Proof ctxt))

        (fn () => eval verbose Position.none ants) ();

  in (case ! r of NONE => error ("Bad evaluation for " ^ ref_name) | SOME e => e) end) ();

end;

structure Basic_ML_Context: BASIC_ML_CONTEXT = ML_Context;

open Basic_ML_Context;