(*  Title:      Pure/ML/ml_context.ML

     ID:         $Id$

     Author:     Makarius

 ML context and antiquotations.

 *)

 signature BASIC_ML_CONTEXT =

 sig

   val the_context: unit -> theory

   val thm: xstring -> thm

   val thms: xstring -> thm list

 end

 signature ML_CONTEXT =

 sig

   include BASIC_ML_CONTEXT

   val get_context: unit -> Context.generic option

   val set_context: Context.generic option -> unit

   val setmp: Context.generic option -> ('a -> 'b) -> 'a -> 'b

   val the_generic_context: unit -> Context.generic

   val the_local_context: unit -> Proof.context

   val pass: Context.generic option -> ('a -> 'b) -> 'a -> 'b * Context.generic option

   val pass_context: Context.generic -> ('a -> 'b) -> 'a -> 'b * Context.generic

   val save: ('a -> 'b) -> 'a -> 'b

   val >> : (theory -> theory) -> unit

   val add_keywords: string list -> unit

   val inline_antiq: string ->

     (Context.generic * Args.T list -> string * (Context.generic * Args.T list)) -> unit

   val value_antiq: string ->

     (Context.generic * Args.T list -> (string * string) * (Context.generic * Args.T list)) -> unit

   val proj_value_antiq: string -> (Context.generic * Args.T list ->

       (string * string * string) * (Context.generic * Args.T list)) -> unit

   val eval_antiquotes_fn: (string * Position.T -> string * string) ref  (* FIXME tmp *)

   val trace: bool ref

   val use_mltext: bool -> Position.T -> string -> Context.generic option -> unit

   val use_mltext_update: bool -> Position.T -> string -> Context.generic -> Context.generic

   val use_let: Position.T -> string -> string -> string -> Context.generic -> Context.generic

   val use: Path.T -> unit

   val evaluate: (string -> unit) * (string -> 'b) -> bool ->

     string * (unit -> 'a) option ref -> string -> 'a

 end

 structure ML_Context: ML_CONTEXT =

 struct

 (** Implicit ML context **)

 local

   val current_context = ref (NONE: Context.generic option);

 in

   fun get_context () = ! current_context;

   fun set_context opt_context = current_context := opt_context;

   fun setmp opt_context f x = Library.setmp current_context opt_context f x;

 end;

 fun the_generic_context () =

   (case get_context () of

     SOME context => context

   | _ => error "Unknown context");

 val the_local_context = Context.proof_of o the_generic_context;

 val the_context = Context.theory_of o the_generic_context;

 fun pass opt_context f x =

   setmp opt_context (fn x => let val y = f x in (y, get_context ()) end) x;

 fun pass_context context f x =

   (case pass (SOME context) f x of

     (y, SOME context') => (y, context')

   | (_, NONE) => error "Lost context in ML");

 fun save f x = NAMED_CRITICAL "ML" (fn () => setmp (get_context ()) f x);

 fun change_theory f = NAMED_CRITICAL "ML" (fn () =>

   set_context (SOME (Context.map_theory f (the_generic_context ()))));

 (** ML antiquotations **)

 (* maintain keywords *)

 val global_lexicon = ref Scan.empty_lexicon;

 fun add_keywords keywords = CRITICAL (fn () =>

   change global_lexicon (Scan.extend_lexicon (map Symbol.explode keywords)));

 (* maintain commands *)

 datatype antiq = Inline of string | ProjValue of string * string * string;

 val global_parsers = ref (Symtab.empty:

   (Context.generic * Args.T list -> antiq * (Context.generic * Args.T list)) Symtab.table);

 local

 fun add_item kind 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 >> kind) tab)));

 in

 val inline_antiq = add_item Inline;

 val proj_value_antiq = add_item ProjValue;

 fun value_antiq name scan = proj_value_antiq name (scan >> (fn (a, s) => (a, s, "")));

 end;

 (* command syntax *)

 fun syntax scan src =

   #1 (Args.context_syntax "ML antiquotation" scan src (the_local_context ()));

 fun command src =

   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 => syntax scan src)

   end;

 (* outer syntax *)

 structure T = OuterLex;

 structure P = OuterParse;

 val antiq =

   P.!!! (P.position P.xname -- P.arguments --| Scan.ahead P.eof)

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

 (* input/output wrappers *)

 local

 val isabelle_struct = enclose "structure Isabelle =\nstruct\n" "end;";

 val isabelle_struct0 = isabelle_struct "";

 fun eval_antiquotes txt_pos =

   let

     val ants = Antiquote.scan_antiquotes txt_pos;

     fun expand (Antiquote.Text s) names = (("", Symbol.escape s), names)

       | expand (Antiquote.Antiq x) names =

           (case command (Antiquote.scan_arguments (! global_lexicon) antiq x) of

             Inline s => (("", s), names)

           | ProjValue (a, s, f) =>

               let

                 val a' = if ML_Syntax.is_identifier a then a else "val";

                 val ([b], names') = Name.variants [a'] names;

                 val binding = "val " ^ b ^ " = " ^ s ^ ";\n";

                 val value =

                   if f = "" then "Isabelle." ^ b

                   else "(" ^ f ^ " Isabelle." ^ b ^ ")";

               in ((binding, value), names') end);

     val (decls, body) =

       NAMED_CRITICAL "ML" (fn () => fold_map expand ants ML_Syntax.reserved)

       |> #1 |> split_list |> pairself implode;

   in (isabelle_struct decls, body) end;

 in

 val eval_antiquotes_fn = ref eval_antiquotes;

 val trace = ref false;

 fun eval_wrapper pr verbose pos txt =

   let

     val (txt1, txt2) = ! eval_antiquotes_fn (txt, pos);  (* FIXME tmp hook *)

     val _ = if ! trace then tracing (cat_lines [txt1, txt2]) else ();

     fun eval p =

       use_text (the_default 1 (Position.line_of p), the_default "ML" (Position.file_of p)) pr;

   in

     NAMED_CRITICAL "ML" (fn () =>

      (eval Position.none false txt1;

       eval pos verbose txt2;

       eval Position.none false isabelle_struct0))

   end;

 end;

 (* ML evaluation *)

 fun use_mltext verbose pos txt opt_context =

   setmp opt_context (fn () => eval_wrapper Output.ml_output verbose pos txt) ();

 fun use_mltext_update verbose pos txt context =

   #2 (pass_context context (fn () => eval_wrapper Output.ml_output verbose pos txt) ());

 fun use_let pos bind body txt =

   use_mltext_update false pos

     ("ML_Context.set_context (SOME (let " ^ bind ^ " = " ^ txt ^ " in " ^ body ^

       " end (ML_Context.the_generic_context ())));");

 fun use path = eval_wrapper Output.ml_output true (Position.path path) (File.read path);

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

   let

     val _ = r := NONE;

     val _ = 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) ();

 (* basic antiquotations *)

 fun context x = (Scan.state >> Context.proof_of) x;

 local

 val _ = value_antiq "context" (Scan.succeed ("context", "ML_Context.the_local_context ()"));

 val _ = inline_antiq "sort" (context -- Scan.lift Args.name >> (fn (ctxt, s) =>

   ML_Syntax.atomic (ML_Syntax.print_sort (Syntax.read_sort ctxt s))));

 val _ = inline_antiq "typ" (Args.typ >> (ML_Syntax.atomic o ML_Syntax.print_typ));

 val _ = inline_antiq "term" (Args.term >> (ML_Syntax.atomic o ML_Syntax.print_term));

 val _ = inline_antiq "prop" (Args.prop >> (ML_Syntax.atomic o ML_Syntax.print_term));

 val _ = value_antiq "ctyp" (Args.typ >> (fn T =>

   ("ctyp",

     "Thm.ctyp_of (ML_Context.the_context ()) " ^ ML_Syntax.atomic (ML_Syntax.print_typ T))));

 val _ = value_antiq "cterm" (Args.term >> (fn t =>

   ("cterm",

     "Thm.cterm_of (ML_Context.the_context ()) " ^ ML_Syntax.atomic (ML_Syntax.print_term t))));

 val _ = value_antiq "cprop" (Args.prop >> (fn t =>

   ("cprop",

     "Thm.cterm_of (ML_Context.the_context ()) " ^ ML_Syntax.atomic (ML_Syntax.print_term t))));

 fun type_ syn = (context -- Scan.lift Args.name >> (fn (ctxt, c) =>

     #1 (Term.dest_Type (ProofContext.read_tyname ctxt c))

     |> syn ? Sign.base_name

     |> ML_Syntax.print_string));

 val _ = inline_antiq "type_name" (type_ false);

 val _ = inline_antiq "type_syntax" (type_ true);

 fun const syn = context -- Scan.lift Args.name >> (fn (ctxt, c) =>

   #1 (Term.dest_Const (ProofContext.read_const_proper ctxt c))

   |> syn ? ProofContext.const_syntax_name ctxt

   |> ML_Syntax.print_string);

 val _ = inline_antiq "const_name" (const false);

 val _ = inline_antiq "const_syntax" (const true);

 val _ = inline_antiq "const"

   (context -- Scan.lift Args.name --

     Scan.optional (Scan.lift (Args.$$$ "(") |-- Args.enum1 "," Args.typ --| Scan.lift (Args.$$$ ")")) []

     >> (fn ((ctxt, c), Ts) =>

       let

         val (c, _) = Term.dest_Const (ProofContext.read_const_proper ctxt c);

       in ML_Syntax.atomic (ML_Syntax.print_term (ProofContext.mk_const ctxt (c, Ts))) end));

 in val _ = () end;

 (** fact references **)

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

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

 local

 fun print_interval (Facts.FromTo arg) =

       "Facts.FromTo " ^ ML_Syntax.print_pair ML_Syntax.print_int ML_Syntax.print_int arg

   | print_interval (Facts.From i) = "Facts.From " ^ ML_Syntax.print_int i

   | print_interval (Facts.Single i) = "Facts.Single " ^ ML_Syntax.print_int i;

 fun thm_antiq kind get get_name = value_antiq kind

   (context -- Scan.lift (Args.position Args.name -- Scan.option Args.thm_sel)

   >> (fn (ctxt, ((name, pos), sel)) =>

       let

         val _ = get ctxt (Facts.Named ((name, pos), sel));

         val txt =

           "(Facts.Named ((" ^ ML_Syntax.print_string name ^ ", Position.none), " ^

             ML_Syntax.print_option (ML_Syntax.print_list print_interval) sel ^ "))";

       in (name, get_name ^ " (ML_Context.the_local_context ()) " ^ txt) end));

 in

 val _ = add_keywords ["(", ")", "-", ","];

 val _ = thm_antiq "thm" ProofContext.get_fact_single "ProofContext.get_fact_single";

 val _ = thm_antiq "thms" ProofContext.get_fact "ProofContext.get_fact";

 end;

 val _ = proj_value_antiq "cpat" (Scan.lift Args.name >>

     (fn name => ("cpat",

       "Thm.cterm_of (ML_Context.the_context ()) (Syntax.read_term \

       \(ProofContext.set_mode ProofContext.mode_pattern (ML_Context.the_local_context ()))"

       ^ ML_Syntax.print_string name ^ ")", "")));

 (*final declarations of this structure!*)

 nonfix >>;

 fun >> f = change_theory f;

 end;

 structure Basic_ML_Context: BASIC_ML_CONTEXT = ML_Context;

 open Basic_ML_Context;