(* 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 =
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
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;