(*  Title:      Pure/Syntax/printer.ML

    ID:         $Id$

    Author:     Tobias Nipkow and Markus Wenzel, TU Muenchen

Pretty printing of asts, terms, types and print (ast) translation.

*)

signature PRINTER0 =

sig

  val show_types: bool ref

  val show_sorts: bool ref

end;

signature PRINTER =

sig

  include PRINTER0

  structure Symtab: SYMTAB

  structure XGram: XGRAM

  structure Pretty: PRETTY

  local open XGram XGram.Ast in

    val term_to_ast: (string -> (term list -> term) option) -> term -> ast

    val typ_to_ast: (string -> (term list -> term) option) -> typ -> ast

    type prtab

    val empty_prtab: prtab

    val extend_prtab: prtab -> (string prod list) -> (string * (ast list -> ast)) list

      -> prtab

    val mk_prtab: (string prod list) -> (string * (ast list -> ast)) list -> prtab

    val pretty_term_ast: prtab -> ast -> Pretty.T

    val pretty_typ_ast: prtab -> ast -> Pretty.T

  end

end;

functor PrinterFun(structure Symtab: SYMTAB and Lexicon: LEXICON

  and TypeExt: TYPE_EXT and SExtension: SEXTENSION and Pretty: PRETTY

  sharing TypeExt.Extension = SExtension.Extension) (*: PRINTER *) =  (* FIXME *)

struct

structure Symtab = Symtab;

structure Extension = TypeExt.Extension;

structure XGram = Extension.XGram;

structure Pretty = Pretty;

open XGram XGram.Ast Lexicon TypeExt Extension SExtension;

(** options for printing **)

val show_types = ref false;

val show_sorts = ref false;

(** convert term or typ to ast **)

fun apply_trans name a f args =

  (f args handle

    Match => raise Match

  | exn => (writeln ("Error in " ^ name ^ " for " ^ quote a); raise exn));

fun ast_of_term trf show_types show_sorts tm =

  let

(*(* FIXME old - remove *)

    fun fix_aprop tys (Abs (x, ty, t)) = Abs (x, ty, fix_aprop (ty :: tys) t)

      | fix_aprop tys t =

          let

            val (f, args) = strip_comb t;

            val t' = list_comb (f, map (fix_aprop tys) args);

          in

            if not (is_Const f) andalso fastype_of (tys, t) = propT

            then Const (apropC, dummyT) $ t' else t'

          end;

    val aprop_const = Const (apropC, dummyT);

    fun fix_aprop (tm as Const _) = tm

      | fix_aprop (tm as Free (x, ty)) =

          if ty = propT then aprop_const $ Free (x, dummyT) else tm

      | fix_aprop (tm as Var (xi, ty)) =

          if ty = propT then aprop_const $ Var (xi, dummyT) else tm

      | fix_aprop (tm as Bound _) = tm

      | fix_aprop (Abs (x, ty, t)) = Abs (x, ty, fix_aprop t)

      | fix_aprop (t1 $ t2) = fix_aprop t1 $ fix_aprop t2;

    val fix_aprop = fn _ => fn tm => fix_aprop tm;

*)

    (* FIXME check *)

    fun aprop t = Const (apropC, dummyT) $ t;

    fun is_prop tys tm =

      fastype_of (tys, tm) = propT handle TERM _ => false;

    fun fix_aprop _ (tm as Const _) = tm

      | fix_aprop _ (tm as Free (x, ty)) =

          if ty = propT then aprop (Free (x, dummyT)) else tm

      | fix_aprop _ (tm as Var (xi, ty)) =

          if ty = propT then aprop (Var (xi, dummyT)) else tm

      | fix_aprop tys (tm as Bound _) =

          if is_prop tys tm then aprop tm else tm

      | fix_aprop tys (Abs (x, ty, t)) = Abs (x, ty, fix_aprop (ty :: tys) t)

      | fix_aprop tys (tm as t1 $ t2) =

          (if is_Const (head_of tm) orelse not (is_prop tys tm)

            then I else aprop) (fix_aprop tys t1 $ fix_aprop tys t2);

    fun prune_typs (t_seen as (Const _, _)) = t_seen

      | prune_typs (t as Free (x, ty), seen) =

          if ty = dummyT then (t, seen)

          else if t mem seen then (Free (x, dummyT), seen)

          else (t, t :: seen)

      | prune_typs (t as Var (xi, ty), seen) =

          if ty = dummyT then (t, seen)

          else if t mem seen then (Var (xi, dummyT), seen)

          else (t, t :: seen)

      | prune_typs (t_seen as (Bound _, _)) = t_seen

      | prune_typs (Abs (x, ty, t), seen) =

          let val (t', seen') = prune_typs (t, seen);

          in (Abs (x, ty, t'), seen') end

      | prune_typs (t1 $ t2, seen) =

          let

            val (t1', seen') = prune_typs (t1, seen);

            val (t2', seen'') = prune_typs (t2, seen');

          in

            (t1' $ t2', seen'')

          end;

    fun ast_of (Const (a, _)) = trans a []

      | ast_of (Free (x, ty)) = constrain x (Free (x, dummyT)) ty

      | ast_of (Var (xi, ty)) = constrain (string_of_vname xi) (Var (xi, dummyT)) ty

      | ast_of (Bound i) = Variable ("B." ^ string_of_int i)

      | ast_of (t as Abs _) = ast_of (abs_tr' t)

      | ast_of (t as _ $ _) =

          (case strip_comb t of

            (Const (a, _), args) => trans a args

          | (f, args) => Appl (map ast_of (f :: args)))

    and trans a args =

      (case trf a of

        Some f => ast_of (apply_trans "print translation" a f args)

      | None => raise Match)

          handle Match => mk_appl (Constant a) (map ast_of args)

    and constrain x t ty =

      if show_types andalso ty <> dummyT then

        ast_of (Const (constrainC, dummyT) $ t $ term_of_typ show_sorts ty)

      else Variable x;

  in

    if show_types then ast_of (#1 (prune_typs (fix_aprop [] tm, [])))

    else ast_of (fix_aprop [] tm)

  end;

(* term_to_ast *)

fun term_to_ast trf tm =

  ast_of_term trf (! show_types) (! show_sorts) tm;

(* typ_to_ast *)

fun typ_to_ast trf ty =

  ast_of_term trf false false (term_of_typ (! show_sorts) ty);

(** type prtab **)

datatype symb =

  Arg of int |

  TypArg of int |

  String of string |

  Break of int |

  Block of int * symb list;

datatype format =

  Prnt of symb list * int * int |

  Trns of ast list -> ast |

  TorP of (ast list -> ast) * (symb list * int * int);

type prtab = format Symtab.table;

(* empty_prtab *)

val empty_prtab = Symtab.null;

(** extend_prtab **)

fun extend_prtab prtab prods trfuns =

  let

    fun nargs (Arg _ :: symbs) = nargs symbs + 1

      | nargs (TypArg _ :: symbs) = nargs symbs + 1

      | nargs (String _ :: symbs) = nargs symbs

      | nargs (Break _ :: symbs) = nargs symbs

      | nargs (Block (_, bsymbs) :: symbs) = nargs symbs + nargs bsymbs

      | nargs [] = 0;

    fun merge (s, String s' :: l) = String (s ^ s') :: l

      | merge (s, l) = String s :: l;

    fun mk_prnp sy c p =

      let

        val constr = (c = constrainC orelse c = constrainIdtC);

        fun syn2pr (Terminal s :: sy) =

              let val (symbs, sy') = syn2pr sy;

              in (merge (s, symbs), sy') end

          | syn2pr (Space s :: sy) =

              let val (symbs, sy') = syn2pr sy;

              in (merge (s, symbs), sy') end

          | syn2pr (Nonterminal (s, p) :: sy) =

              let

                val (symbs, sy') = syn2pr sy;

                val symb =

                  (if constr andalso s = "type" then TypArg else Arg)

                    (if is_terminal s then 0 else p);

              in (symb :: symbs, sy') end

          | syn2pr (Bg i :: sy) =

              let

                val (bsymbs, sy') = syn2pr sy;

                val (symbs, sy'') = syn2pr sy';

              in (Block (i, bsymbs) :: symbs, sy'') end

          | syn2pr (Brk i :: sy) =

              let val (symbs, sy') = syn2pr sy;

              in (Break i :: symbs, sy') end

          | syn2pr (En :: sy) = ([], sy)

          | syn2pr [] = ([], []);

        val (pr, _) = syn2pr sy;

      in

        (pr, nargs pr, p)

      end;

    fun trns_err c = error ("More than one parse ast translation for " ^ quote c);

    fun add_fmt tab c fmt x = Symtab.update ((c, fmt x), tab);

    fun add_prod (tab, Prod (_, _, "", _)) = tab

      | add_prod (tab, Prod (_, sy, c, p)) =

          (case Symtab.lookup (tab, c) of

            None => add_fmt tab c Prnt (mk_prnp sy c p)

          | Some (Prnt _) => add_fmt tab c Prnt (mk_prnp sy c p)

          | Some (Trns f) => add_fmt tab c TorP (f, mk_prnp sy c p)

          | Some (TorP (f, _)) => add_fmt tab c TorP (f, mk_prnp sy c p));

    fun add_tr (tab, (c, f)) =

      (case Symtab.lookup (tab, c) of

        None => add_fmt tab c Trns f

      | Some (Prnt pr) => add_fmt tab c TorP (f, pr)

      | Some (Trns _) => trns_err c

      | Some (TorP _) => trns_err c);

  in

    Symtab.balance (foldl add_prod (foldl add_tr (prtab, trfuns), prods))

  end;

(* mk_prtab *)

val mk_prtab = extend_prtab empty_prtab;

(** pretty term/typ asts **)

(*pretty assumes a syntax derived from Pure, otherwise it may loop forever*)

fun pretty tab type_mode ast0 p0 =

  let

    val trans = apply_trans "print ast translation";

    val appT = if type_mode then tappl_ast_tr' else appl_ast_tr';

    fun synT ([], args) = ([], args)

      | synT (Arg p :: symbs, t :: args) =

          let val (Ts, args') = synT (symbs, args);

          in (astT (t, p) @ Ts, args') end

      | synT (TypArg p :: symbs, t :: args) =

          let val (Ts, args') = synT (symbs, args);

          in (pretty tab true t p @ Ts, args') end

      | synT (String s :: symbs, args) =

          let val (Ts, args') = synT (symbs, args);

          in (Pretty.str s :: Ts, args') end

      | synT (Block (i, bsymbs) :: symbs, args) =

          let

            val (bTs, args') = synT (bsymbs, args);

            val (Ts, args'') = synT (symbs, args');

          in (Pretty.blk (i, bTs) :: Ts, args'') end

      | synT (Break i :: symbs, args) =

          let val (Ts, args') = synT (symbs, args);

          in ((if i < 0 then Pretty.fbrk else Pretty.brk i) :: Ts, args') end

      | synT (_ :: _, []) = error "synT"

    and parT (pr, args, p, p': int) =

      if p > p' then

        #1 (synT ([Block (1, String "(" :: pr @ [String ")"])], args))

      else #1 (synT (pr, args))

    and prefixT (_, a, [], _) = [Pretty.str a]

      | prefixT (c, _, args, p) = astT (appT (c, args), p)

    and splitT 0 ([x], ys) = (x, ys)

      | splitT 0 (rev_xs, ys) = (Appl (rev rev_xs), ys)

      | splitT n (rev_xs, y :: ys) = splitT (n - 1) (y :: rev_xs, ys)

      | splitT _ _ = error "splitT"

    and combT (tup as (c, a, args, p)) =

      let

        val nargs = length args;

        fun prnt (pr, n, p') =

          if nargs = n then parT (pr, args, p, p')

          else if nargs < n orelse type_mode then prefixT tup

          else astT (appT (splitT n ([c], args)), p);

      in

        (case Symtab.lookup (tab, a) of

          None => prefixT tup

        | Some (Prnt prnp) => prnt prnp

        | Some (Trns f) =>

            (astT (trans a f args, p) handle Match => prefixT tup)

        | Some (TorP (f, prnp)) =>

            (astT (trans a f args, p) handle Match => prnt prnp))

      end

    and astT (c as Constant a, p) = combT (c, a, [], p)

      | astT (Variable x, _) = [Pretty.str x]

      | astT (Appl ((c as Constant a) :: (args as _ :: _)), p) =

          combT (c, a, args, p)

      | astT (Appl (f :: (args as _ :: _)), p) = astT (appT (f, args), p)

      | astT (ast as Appl _, _) = raise_ast "pretty: malformed ast" [ast];

  in

    astT (ast0, p0)

  end;

(* pretty_term_ast *)

fun pretty_term_ast tab ast =

  Pretty.blk (0, pretty tab false ast 0);

(* pretty_typ_ast *)

fun pretty_typ_ast tab ast =

  Pretty.blk (0, pretty tab true ast 0);

end;