(* Auxiliary antiquotations for the tutorial. *)

structure AntiquoteSetup: sig end =

struct

(* functions for generating appropriate expressions *)

fun ml_val_open (ys, xs) txt = 

  let fun ml_val_open_aux ys txt = 

          "fn " ^ (case ys of [] => "_" | _ => enclose "(" ")" (commas ys)) ^ " => (" ^ txt ^ ")";

  in

    (case xs of

       [] => ml_val_open_aux ys txt

     | _  => ml_val_open_aux ys ("let open " ^ (space_implode " " xs) ^ " in " ^ txt ^ " end"))

  end;

fun ml_val txt = ml_val_open ([],[]) txt;

fun ml_pat (lhs, pat) =

  let 

     val pat' = implode (map (fn "\\<dots>" => "_" | s => s) (Symbol.explode pat))

  in "val " ^ pat' ^ " = " ^ lhs end;

fun ml_struct txt = "functor DUMMY_FUNCTOR() = struct structure DUMMY = " ^ txt ^ " end";

fun ml_type txt = "val _ = NONE : (" ^ txt ^ ") option";

(* eval function *)

fun eval_fn ctxt exp =

  ML_Context.eval_in (SOME ctxt) false Position.none exp

(* string functions *)

fun string_explode str txt =

  map (fn s => str ^ s) (space_explode "\n" txt)

val transform_cmts_str =

     Source.of_string 

  #> ML_Lex.source 

  #> Source.exhaust 

  #> Chunks.transform_cmts 

  #> implode 

  #> string_explode "";

(* output function *)

fun output_fn txt =  Chunks.output (map Pretty.str txt)

(* checks and prints open expressions *)

fun output_ml {context = ctxt, ...} (txt, ovars) =

  (eval_fn ctxt (ml_val_open ovars txt);

   output_fn (transform_cmts_str txt))

val parser_ml = Scan.lift (Args.name --

  (Scan.optional (Args.$$$ "for" |-- OuterParse.!!! (Scan.repeat1 Args.name)) [] --

   Scan.optional (Args.$$$ "in"  |-- OuterParse.!!! (Scan.repeat1 Args.name)) [])) 

(* checks and prints types and structures *)

fun output_exp ml {context = ctxt, ...} txt = 

  (eval_fn ctxt (ml txt);

   output_fn (string_explode "" txt))

(* checks and expression agains a result pattern *)

fun output_response {context = ctxt, ...} (lhs, pat) = 

    (eval_fn ctxt (ml_pat (lhs, pat));

     output_fn ((string_explode "" lhs) @ (string_explode "> " pat)))

(* checks the expressions, but does not check it against a result pattern *)

fun output_response_fake {context = ctxt, ...} (lhs, pat) = 

    (eval_fn ctxt (ml_val lhs);

     output_fn ((string_explode "" lhs) @ (string_explode "> " pat)))

(* checks the expressions, but does not check it against a result pattern *)

fun ouput_response_fake_both _ (lhs, pat) = 

    output_fn ((string_explode "" lhs) @ (string_explode "> " pat))

val single_arg = Scan.lift (Args.name)

val two_args   = Scan.lift (Args.name -- Args.name)

val _ = ThyOutput.antiquotation "ML" parser_ml output_ml

val _ = ThyOutput.antiquotation "ML_type" single_arg (output_exp ml_type)

val _ = ThyOutput.antiquotation "ML_struct" single_arg (output_exp ml_struct)

val _ = ThyOutput.antiquotation "ML_response" two_args output_response

val _ = ThyOutput.antiquotation "ML_response_fake" two_args output_response_fake

val _ = ThyOutput.antiquotation "ML_response_fake_both" two_args ouput_response_fake_both

(* checks whether a file exists in the Isabelle distribution *)

fun check_file_exists _ txt =

  (if File.exists (Path.append (Path.explode ("~~/src")) (Path.explode txt)) 

   then output_fn (string_explode "" txt)

   else error ("Source file " ^ (quote txt) ^ " does not exist."))

val _ = ThyOutput.antiquotation "ML_file" single_arg check_file_exists

(* replaces the official subgoal antiquotation with one *)

(* that is closer to the actual output                  *)

fun output_goals  {state = node, ...}  _ = 

let

  fun subgoals 0 = ""

    | subgoals 1 = "goal (1 subgoal):"

    | subgoals n = "goal (" ^ string_of_int n ^ " subgoals):"

  fun proof_state state =

    (case try Toplevel.proof_of state of

      SOME prf => prf

    | _ => error "No proof state")

  val state = proof_state node;

  val goals = Proof.pretty_goals false state;

  val {prop, ...} = rep_thm (Proof.get_goal state |> snd |> snd);

  val (As, B) = Logic.strip_horn prop;

  val output  = (case (length As) of

                      0 => goals 

                    | n => (Pretty.str (subgoals n))::goals)  

in 

  ThyOutput.output output

end

val _ = ThyOutput.antiquotation "subgoals" (Scan.succeed ()) output_goals

end;