src/Pure/ML/ml_context.ML

eliminated old 'axclass';
misc tuning and modernization;

(*  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 inherit_env: Proof.context -> Proof.context -> Proof.context
  val name_space: ML_NameSpace.nameSpace
  val stored_thms: thm list ref
  val ml_store_thm: string * thm -> unit
  val ml_store_thms: string * thm list -> unit
  type antiq =
    {struct_name: string, background: Proof.context} ->
      (Proof.context -> string * string) * Proof.context
  val add_antiq: string ->
    (Position.T -> Context.generic * Args.T list -> antiq * (Context.generic * Args.T list)) -> unit
  val trace: bool ref
  val eval_wrapper: (string -> unit) * (string -> 'a) -> bool -> Position.T -> string -> unit
  val eval: bool -> Position.T -> string -> unit
  val eval_file: Path.T -> unit
  val eval_in: Proof.context option -> bool -> Position.T -> string -> unit
  val evaluate: Proof.context -> (string -> unit) * (string -> 'b) -> bool ->
    string * (unit -> 'a) option ref -> string -> 'a
  val expression: Position.T -> string -> string -> string -> Context.generic -> Context.generic
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");


(* ML name space *)

structure ML_Env = GenericDataFun
(
  type T =
    ML_NameSpace.valueVal Symtab.table *
    ML_NameSpace.typeVal Symtab.table *
    ML_NameSpace.fixityVal Symtab.table *
    ML_NameSpace.structureVal Symtab.table *
    ML_NameSpace.signatureVal Symtab.table *
    ML_NameSpace.functorVal Symtab.table;
  val empty = (Symtab.empty, Symtab.empty, Symtab.empty, Symtab.empty, Symtab.empty, Symtab.empty);
  val extend = I;
  fun merge _
   ((val1, type1, fixity1, structure1, signature1, functor1),
    (val2, type2, fixity2, structure2, signature2, functor2)) : T =
   (Symtab.merge (K true) (val1, val2),
    Symtab.merge (K true) (type1, type2),
    Symtab.merge (K true) (fixity1, fixity2),
    Symtab.merge (K true) (structure1, structure2),
    Symtab.merge (K true) (signature1, signature2),
    Symtab.merge (K true) (functor1, functor2));
);

val inherit_env = Context.proof_map o ML_Env.put o ML_Env.get o Context.Proof;

val name_space: ML_NameSpace.nameSpace =
  let
    fun lookup sel1 sel2 name =
      Context.thread_data ()
      |> (fn NONE => NONE | SOME context => Symtab.lookup (sel1 (ML_Env.get context)) name)
      |> (fn NONE => sel2 ML_NameSpace.global name | some => some);

    fun all sel1 sel2 () =
      Context.thread_data ()
      |> (fn NONE => [] | SOME context => Symtab.dest (sel1 (ML_Env.get context)))
      |> append (sel2 ML_NameSpace.global ())
      |> sort_distinct (string_ord o pairself #1);

    fun enter ap1 sel2 entry =
      if is_some (Context.thread_data ()) then
        Context.>> (ML_Env.map (ap1 (Symtab.update entry)))
      else sel2 ML_NameSpace.global entry;
  in
   {lookupVal    = lookup #1 #lookupVal,
    lookupType   = lookup #2 #lookupType,
    lookupFix    = lookup #3 #lookupFix,
    lookupStruct = lookup #4 #lookupStruct,
    lookupSig    = lookup #5 #lookupSig,
    lookupFunct  = lookup #6 #lookupFunct,
    enterVal     = enter (fn h => fn (a, b, c, d, e, f) => (h a, b, c, d, e, f)) #enterVal,
    enterType    = enter (fn h => fn (a, b, c, d, e, f) => (a, h b, c, d, e, f)) #enterType,
    enterFix     = enter (fn h => fn (a, b, c, d, e, f) => (a, b, h c, d, e, f)) #enterFix,
    enterStruct  = enter (fn h => fn (a, b, c, d, e, f) => (a, b, c, h d, e, f)) #enterStruct,
    enterSig     = enter (fn h => fn (a, b, c, d, e, f) => (a, b, c, d, h e, f)) #enterSig,
    enterFunct   = enter (fn h => fn (a, b, c, d, e, f) => (a, b, c, d, e, h f)) #enterFunct,
    allVal       = all #1 #allVal,
    allType      = all #2 #allType,
    allFix       = all #3 #allFix,
    allStruct    = all #4 #allStruct,
    allSig       = all #5 #allSig,
    allFunct     = all #6 #allFunct}
  end;


(* theorem bindings *)

val stored_thms: thm list ref = ref [];

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 stored_thms ths' (fn () =>
        use_text name_space (0, "") Output.ml_output true
          ("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.standard thm);
fun bind_thms (name, thms) = ml_store_thms (name, map Drule.standard 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 =
  {struct_name: string, background: Proof.context} ->
    (Proof.context -> string * string) * Proof.context;

local

val global_parsers = ref (Symtab.empty:
  (Position.T -> Context.generic * Args.T list -> antiq * (Context.generic * Args.T list))
    Symtab.table);

in

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

structure P = OuterParse;

val antiq =
  P.!!! (P.position P.xname -- Args.parse --| Scan.ahead P.eof)
  >> (fn ((x, pos), y) => Args.src ((x, y), pos));

val struct_name = "Isabelle";

fun eval_antiquotes (txt, pos) opt_context =
  let
    val syms = SymbolPos.explode (txt, pos);
    val ants = Antiquote.read (syms, pos);
    val opt_ctxt = Option.map (Context.Proof o Context.proof_of) opt_context;
    val ((ml_env, ml_body), opt_ctxt') =
      if not (exists Antiquote.is_antiq ants)
      then (("", Symbol.escape (SymbolPos.content syms)), opt_ctxt)
      else
        let
          val ctxt =
            (case opt_ctxt of
              NONE => error ("Unknown context -- cannot expand ML antiquotations" ^
                Position.str_of pos)
            | SOME ctxt => Context.proof_of ctxt);

          val lex = #1 (OuterKeyword.get_lexicons ());
          fun no_decl _ = ("", "");

          fun expand (Antiquote.Text s) state = (K ("", Symbol.escape s), state)
            | expand (Antiquote.Antiq x) (scope, background) =
                let
                  val context = Stack.top scope;
                  val (f, context') = antiquotation (Antiquote.read_antiq lex antiq x) context;
                  val (decl, background') = f {background = background, struct_name = struct_name};
                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 implode;
        in (ml, SOME (Context.Proof ctxt')) end;
  in (("structure " ^ struct_name ^ " =\nstruct\n" ^ ml_env ^ "end;", ml_body), opt_ctxt') end;

in

val trace = ref false;

fun eval_wrapper pr verbose pos txt =
  let
    fun eval_raw p = use_text name_space
      (the_default 1 (Position.line_of p), the_default "ML" (Position.file_of p)) pr;

    (*prepare source text*)
    val _ = Position.report Markup.ML_source pos;
    val ((env, body), env_ctxt) = eval_antiquotes (txt, pos) (Context.thread_data ());
    val _ = if ! trace then tracing (cat_lines [env, body]) else ();

    (*prepare static ML environment*)
    val _ = Context.setmp_thread_data env_ctxt
        (fn () => (eval_raw Position.none false env; Context.thread_data ())) ()
      |> (fn NONE => () | SOME context' => Context.>> (ML_Env.put (ML_Env.get context')));

    (*eval ML*)
    val _ = eval_raw pos verbose body;

    (*reset static ML environment*)
    val _ = eval_raw Position.none false "structure Isabelle = struct end";
  in () end;

end;


(* ML evaluation *)

val eval = eval_wrapper Output.ml_output;
fun eval_file path = eval true (Path.position path) (File.read path);

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

fun evaluate ctxt pr verbose (ref_name, r) txt = NAMED_CRITICAL "ML" (fn () =>
  let
    val _ = r := NONE;
    val _ = Context.setmp_thread_data (SOME (Context.Proof ctxt)) (fn () =>
      eval_wrapper pr verbose Position.none
        ("val _ = (" ^ ref_name ^ " := SOME (fn () => " ^ txt ^ "))")) ();
  in (case ! r of NONE => error ("Bad evaluation for " ^ ref_name) | SOME e => e) end) ();

fun expression pos bind body txt =
  exec (fn () => eval false pos
    ("Context.set_thread_data (SOME (let " ^ bind ^ " = " ^ txt ^ " in " ^ body ^
      " end (ML_Context.the_generic_context ())));"));

end;

structure Basic_ML_Context: BASIC_ML_CONTEXT = ML_Context;
open Basic_ML_Context;