diff --git a/src/Pure/Syntax/syntax_ext.ML b/src/Pure/Syntax/syntax_ext.ML
--- a/src/Pure/Syntax/syntax_ext.ML
+++ b/src/Pure/Syntax/syntax_ext.ML
@@ -1,433 +1,433 @@
 (*  Title:      Pure/Syntax/syntax_ext.ML
     Author:     Markus Wenzel and Carsten Clasohm, TU Muenchen
 
 Syntax extension.
 *)
 
 signature SYNTAX_EXT =
 sig
   datatype mfix = Mfix of Symbol_Pos.T list * typ * string * int list * int * Position.T
   val typ_to_nonterm: typ -> string
   type block_info = {markup: Markup.T, consistent: bool, unbreakable: bool, indent: int}
   val block_indent: int -> block_info
   datatype xsymb =
     Delim of string |
     Argument of string * int |
     Space of string |
     Bg of block_info |
     Brk of int |
     En
   datatype xprod = XProd of string * xsymb list * string * int
   val chain_pri: int
-  val delims_of: xprod list -> string list list
+  val delims_of: xprod list -> Symbol.symbol list list
   datatype syn_ext =
     Syn_Ext of {
       xprods: xprod list,
       consts: (string * string) list,
       parse_ast_translation: (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list,
       parse_rules: (Ast.ast * Ast.ast) list,
       parse_translation: (string * ((Proof.context -> term list -> term) * stamp)) list,
       print_translation: (string * ((Proof.context -> typ -> term list -> term) * stamp)) list,
       print_rules: (Ast.ast * Ast.ast) list,
       print_ast_translation: (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list}
   val mfix_args: Symbol_Pos.T list -> int
   val mixfix_args: Input.source -> int
   val escape: string -> string
   val syn_ext: string list -> mfix list ->
     (string * string) list -> (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list *
     (string * ((Proof.context -> term list -> term) * stamp)) list *
     (string * ((Proof.context -> typ -> term list -> term) * stamp)) list *
     (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list ->
     (Ast.ast * Ast.ast) list * (Ast.ast * Ast.ast) list -> syn_ext
   val syn_ext_rules: (Ast.ast * Ast.ast) list * (Ast.ast * Ast.ast) list -> syn_ext
   val syn_ext_trfuns:
     (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list *
     (string * ((Proof.context -> term list -> term) * stamp)) list *
     (string * ((Proof.context -> typ -> term list -> term) * stamp)) list *
     (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list -> syn_ext
   val stamp_trfun: stamp -> string * 'a -> string * ('a * stamp)
   val mk_trfun: string * 'a -> string * ('a * stamp)
   val eq_trfun: ('a * stamp) * ('a * stamp) -> bool
 end;
 
 structure Syntax_Ext: SYNTAX_EXT =
 struct
 
 (** datatype xprod **)
 
 (*Delim s: delimiter s
   Argument (s, p): nonterminal s requiring priority >= p, or valued token
   Space s: some white space for printing
   Bg, Brk, En: blocks and breaks for pretty printing*)
 
 type block_info = {markup: Markup.T, consistent: bool, unbreakable: bool, indent: int};
 
 fun block_indent indent : block_info =
   {markup = Markup.empty, consistent = false, unbreakable = false, indent = indent};
 
 datatype xsymb =
   Delim of string |
   Argument of string * int |
   Space of string |
   Bg of block_info |
   Brk of int |
   En;
 
 fun is_delim (Delim _) = true
   | is_delim _ = false;
 
 fun is_terminal (Delim _) = true
   | is_terminal (Argument (s, _)) = Lexicon.is_terminal s
   | is_terminal _ = false;
 
 fun is_argument (Argument _) = true
   | is_argument _ = false;
 
 fun is_index (Argument ("index", _)) = true
   | is_index _ = false;
 
 val index = Argument ("index", 1000);
 
 
 (*XProd (lhs, syms, c, p):
     lhs: name of nonterminal on the lhs of the production
     syms: list of symbols on the rhs of the production
     c: head of parse tree
     p: priority of this production*)
 
 datatype xprod = XProd of string * xsymb list * string * int;
 
 val chain_pri = ~1;   (*dummy for chain productions*)
 
 fun delims_of xprods =
   fold (fn XProd (_, xsymbs, _, _) =>
     fold (fn Delim s => insert (op =) s | _ => I) xsymbs) xprods []
   |> map Symbol.explode;
 
 
 
 (** datatype mfix **)
 
 (*Mfix (sy, ty, c, ps, p, pos):
     sy: rhs of production as symbolic text
     ty: type description of production
     c: head of parse tree
     ps: priorities of arguments in sy
     p: priority of production
     pos: source position*)
 
 datatype mfix = Mfix of Symbol_Pos.T list * typ * string * int list * int * Position.T;
 
 
 (* typ_to_nonterm *)
 
 fun typ_to_nt _ (Type (c, _)) = c
   | typ_to_nt default _ = default;
 
 (*get nonterminal for rhs*)
 val typ_to_nonterm = typ_to_nt "any";
 
 (*get nonterminal for lhs*)
 val typ_to_nonterm1 = typ_to_nt "logic";
 
 
 (* properties *)
 
 local
 
 open Basic_Symbol_Pos;
 
 val err_prefix = "Error in mixfix block properties: ";
 val !!! = Symbol_Pos.!!! (fn () => err_prefix ^ "atom expected (identifier, numeral, cartouche)");
 
 val scan_atom =
   Symbol_Pos.scan_ident ||
   ($$$ "-" @@@ (Symbol_Pos.scan_float || Symbol_Pos.scan_nat)) ||
   Symbol_Pos.scan_float || Symbol_Pos.scan_nat ||
   Symbol_Pos.scan_cartouche_content err_prefix;
 
 val scan_blanks = Scan.many (Symbol.is_blank o Symbol_Pos.symbol);
 val scan_item =
   scan_blanks |-- scan_atom --| scan_blanks
     >> (fn ss => (Symbol_Pos.content ss, #1 (Symbol_Pos.range ss)));
 
 val scan_prop =
   scan_item -- Scan.optional ($$ "=" |-- !!! scan_item >> #1) "true"
     >> (fn ((x, pos), y) => (x, (y, pos)));
 
 fun get_property default parse name props =
   (case AList.lookup (op =) props name of
     NONE => default
   | SOME (s, pos) =>
       (parse s handle Fail msg => error (msg ^ " for property " ^ quote name ^ Position.here pos)));
 
 in
 
 fun read_properties ss =
   let
     val props =
       (case Scan.error (Scan.finite Symbol_Pos.stopper (Scan.repeat scan_prop)) ss of
         (props, []) => props
       | (_, (_, pos) :: _) => error (err_prefix ^ "bad input" ^ Position.here pos));
     val _ =
       (case AList.group (op =) props |> filter (fn (_, [_]) => false | _ => true) of
         [] => ()
       | dups => error ("Duplicate properties: " ^ commas_quote (map #1 dups) ^
           Position.here_list (map #2 (maps #2 dups))));
   in props end;
 
 val get_string = get_property "" I;
 val get_bool = get_property false Value.parse_bool;
 val get_nat = get_property 0 Value.parse_nat;
 
 end;
 
 
 (* read mixfix annotations *)
 
 local
 
 open Basic_Symbol_Pos;
 
 val err_prefix = "Error in mixfix annotation: ";
 
 fun scan_one pred = Scan.one (pred o Symbol_Pos.symbol);
 fun scan_many pred = Scan.many (pred o Symbol_Pos.symbol);
 fun scan_many1 pred = Scan.many1 (pred o Symbol_Pos.symbol);
 
 fun reports_of_block pos =
   [(pos, Markup.expression "mixfix block begin"), (pos, Markup.keyword3)];
 
 fun reports_of (xsym, pos) =
   (case xsym of
     Delim _ => [(pos, Markup.expression "mixfix delimiter"), (pos, Markup.literal)]
   | Argument _ => [(pos, Markup.expression "mixfix argument")]
   | Space _ => [(pos, Markup.expression "mixfix space")]
   | Bg _ => reports_of_block pos
   | Brk _ => [(pos, Markup.expression "mixfix break"), (pos, Markup.keyword3)]
   | En => [(pos, Markup.expression "mixfix block end"), (pos, Markup.keyword3)]);
 
 fun reports_text_of (xsym, pos) =
   (case xsym of
     Delim s =>
       if Position.is_reported pos andalso exists Symbol.is_utf8 (Symbol.explode s) then
         [((pos, Markup.bad ()),
           "Mixfix delimiter contains raw Unicode -- this is non-portable and unreliable")]
       else []
   | _ => []);
 
 fun read_block_properties ss =
   let
     val props = read_properties ss;
 
     val markup_name = get_string Markup.markupN props;
     val markup_props = fold (AList.delete (op =)) Markup.block_properties props;
     val markup = (markup_name, map (apsnd #1) markup_props);
     val _ =
       if markup_name = "" andalso not (null markup_props) then
         error ("Markup name required for block properties: " ^
           commas_quote (map #1 markup_props) ^ Position.here_list (map (#2 o #2) markup_props))
       else ();
 
     val consistent = get_bool Markup.consistentN props;
     val unbreakable = get_bool Markup.unbreakableN props;
     val indent = get_nat Markup.indentN props;
   in Bg {markup = markup, consistent = consistent, unbreakable = unbreakable, indent = indent} end
   handle ERROR msg =>
     let
       val reported_texts =
         reports_of_block (#1 (Symbol_Pos.range ss))
         |> map (fn (p, m) => Markup.markup_report (Position.reported_text p m ""))
     in error (msg ^ implode reported_texts) end;
 
 val read_block_indent =
   Bg o block_indent o #1 o Library.read_int o map Symbol_Pos.symbol;
 
 val is_meta = member (op =) ["'", "(", ")", "/", "_", "\<index>", Symbol.open_, Symbol.close];
 
 val scan_delim =
   scan_one Symbol.is_control ::: Symbol_Pos.scan_cartouche "Mixfix error: " ||
   $$ "'" |-- scan_one ((not o Symbol.is_blank) andf Symbol.not_eof) >> single ||
   scan_one ((not o is_meta) andf (not o Symbol.is_blank) andf Symbol.not_eof) >> single;
 
 val scan_sym =
   $$ "_" >> K (Argument ("", 0)) ||
   $$ "\<index>" >> K index ||
   $$ "(" |--
    (Symbol_Pos.scan_cartouche_content err_prefix >> read_block_properties ||
     scan_many Symbol.is_digit >> read_block_indent) ||
   $$ ")" >> K En ||
   $$ "/" -- $$ "/" >> K (Brk ~1) ||
   $$ "/" |-- scan_many Symbol.is_space >> (Brk o length) ||
   scan_many1 Symbol.is_space >> (Space o Symbol_Pos.content) ||
   Scan.repeat1 scan_delim >> (Delim o Symbol_Pos.content o flat);
 
 val scan_symb =
   Scan.trace scan_sym >> (fn (syms, trace) => SOME (syms, #1 (Symbol_Pos.range trace))) ||
   $$ "'" -- scan_one Symbol.is_space >> K NONE;
 
 val scan_symbs = Scan.repeat scan_symb --| Scan.ahead (~$$ "'");
 
 in
 
 fun read_mfix ss =
   let
     val xsymbs =
       (case Scan.error (Scan.finite Symbol_Pos.stopper scan_symbs) ss of
         (res, []) => map_filter I res
       | (_, (_, pos) :: _) => error (err_prefix ^ "bad input" ^ Position.here pos));
     val _ = Position.reports (maps reports_of xsymbs);
     val _ = Position.reports_text (maps reports_text_of xsymbs);
   in xsymbs end;
 
 val mfix_args = length o filter (is_argument o #1) o read_mfix o map (apsnd (K Position.none));
 val mixfix_args = mfix_args o Input.source_explode;
 
 val escape = implode o map (fn s => if is_meta s then "'" ^ s else s) o Symbol.explode;
 
 end;
 
 
 (* mfix_to_xprod *)
 
 fun mfix_to_xprod logical_types (Mfix (sy, typ, const, pris, pri, pos)) =
   let
     val _ = Position.report pos Markup.language_mixfix;
     val symbs0 = read_mfix sy;
 
     fun err_in_mixfix msg = error (msg ^ " in mixfix annotation" ^ Position.here pos);
 
     fun check_blocks [] pending bad = pending @ bad
       | check_blocks ((Bg _, pos) :: rest) pending bad = check_blocks rest (pos :: pending) bad
       | check_blocks ((En, pos) :: rest) [] bad = check_blocks rest [] (pos :: bad)
       | check_blocks ((En, _) :: rest) (_ :: pending) bad = check_blocks rest pending bad
       | check_blocks (_ :: rest) pending bad = check_blocks rest pending bad;
 
     fun add_args [] ty [] = ([], typ_to_nonterm1 ty)
       | add_args [] _ _ = err_in_mixfix "Too many precedences"
       | add_args ((sym as (Argument ("index", _), _)) :: syms) ty ps =
           add_args syms ty ps |>> cons sym
       | add_args ((Argument _, pos) :: syms) (Type ("fun", [ty, tys])) [] =
           add_args syms tys [] |>> cons (Argument (typ_to_nonterm ty, 0), pos)
       | add_args ((Argument _, pos) :: syms) (Type ("fun", [ty, tys])) (p :: ps) =
           add_args syms tys ps |>> cons (Argument (typ_to_nonterm ty, p), pos)
       | add_args ((Argument _, _) :: _) _ _ =
           err_in_mixfix "More arguments than in corresponding type"
       | add_args (sym :: syms) ty ps = add_args syms ty ps |>> cons sym;
 
     fun logical_args (a as (Argument (s, p))) =
           if s <> "prop" andalso member (op =) logical_types s then Argument ("logic", p) else a
       | logical_args a = a;
 
     fun rem_pri (Argument (s, _)) = Argument (s, chain_pri)
       | rem_pri sym = sym;
 
     val indexes = filter (is_index o #1) symbs0;
     val _ =
       if length indexes <= 1 then ()
       else error ("More than one index argument" ^ Position.here_list (map #2 indexes));
 
     val args = map_filter (fn (arg as Argument _, _) => SOME arg | _ => NONE) symbs0;
     val (const', typ', syntax_consts, parse_rules) =
       if not (exists is_index args) then (const, typ, NONE, NONE)
       else
         let
           val indexed_const =
             if const <> "" then const ^ "_indexed"
             else err_in_mixfix "Missing constant name for indexed syntax";
           val rangeT = Term.range_type typ handle Match =>
             err_in_mixfix "Missing structure argument for indexed syntax";
 
           val xs = map Ast.Variable (Name.invent Name.context "xa" (length args - 1));
           val (xs1, xs2) = chop (find_index is_index args) xs;
           val i = Ast.Variable "i";
           val lhs =
             Ast.mk_appl (Ast.Constant indexed_const)
               (xs1 @ [Ast.mk_appl (Ast.Constant "_index") [i]] @ xs2);
           val rhs = Ast.mk_appl (Ast.Constant const) (i :: xs);
         in (indexed_const, rangeT, SOME (indexed_const, const), SOME (lhs, rhs)) end;
 
     val (symbs1, lhs) = add_args symbs0 typ' pris;
 
     val copy_prod =
       (lhs = "prop" orelse lhs = "logic")
         andalso const <> ""
         andalso not (null symbs1)
         andalso not (exists (is_delim o #1) symbs1);
     val lhs' =
       if copy_prod orelse lhs = "prop" andalso map #1 symbs1 = [Argument ("prop'", 0)] then lhs
       else if lhs = "prop" then "prop'"
       else if member (op =) logical_types lhs then "logic"
       else lhs;
     val symbs2 = map (apfst logical_args) symbs1;
 
     val _ =
       (pri :: pris) |> List.app (fn p =>
         if p >= 0 andalso p <= 1000 then ()
         else err_in_mixfix ("Precedence " ^ string_of_int p ^ " out of range"));
     val _ =
       (case check_blocks symbs2 [] [] of
         [] => ()
       | bad => error ("Unbalanced block parentheses" ^ Position.here_list bad));
 
     val xprod = XProd (lhs', map #1 symbs2, const', pri);
     val xprod' =
       if Lexicon.is_terminal lhs' then
         err_in_mixfix ("Illegal use of terminal " ^ quote lhs' ^ " as nonterminal")
       else if const <> "" then xprod
       else if length (filter (is_argument o #1) symbs2) <> 1 then
         err_in_mixfix "Copy production must have exactly one argument"
       else if exists (is_terminal o #1) symbs2 then xprod
       else XProd (lhs', map (rem_pri o #1) symbs2, "", chain_pri);
 
   in (xprod', syntax_consts, parse_rules) end;
 
 
 
 (** datatype syn_ext **)
 
 datatype syn_ext =
   Syn_Ext of {
     xprods: xprod list,
     consts: (string * string) list,
     parse_ast_translation: (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list,
     parse_rules: (Ast.ast * Ast.ast) list,
     parse_translation: (string * ((Proof.context -> term list -> term) * stamp)) list,
     print_translation: (string * ((Proof.context -> typ -> term list -> term) * stamp)) list,
     print_rules: (Ast.ast * Ast.ast) list,
     print_ast_translation: (string * ((Proof.context -> Ast.ast list -> Ast.ast) * stamp)) list};
 
 
 (* syn_ext *)
 
 fun syn_ext logical_types mfixes consts trfuns (parse_rules, print_rules) =
   let
     val (parse_ast_translation, parse_translation, print_translation,
       print_ast_translation) = trfuns;
 
     val xprod_results = map (mfix_to_xprod logical_types) mfixes;
     val xprods = map #1 xprod_results;
     val consts' = map_filter #2 xprod_results;
     val parse_rules' = rev (map_filter #3 xprod_results);
     val mfix_consts = map (fn Mfix x => (#3 x, "")) mfixes @ map (fn XProd x => (#3 x, "")) xprods;
   in
     Syn_Ext {
       xprods = xprods,
       consts = mfix_consts @ consts' @ consts,
       parse_ast_translation = parse_ast_translation,
       parse_rules = parse_rules' @ parse_rules,
       parse_translation = parse_translation,
       print_translation = print_translation,
       print_rules = map swap parse_rules' @ print_rules,
       print_ast_translation = print_ast_translation}
   end;
 
 
 fun syn_ext_rules rules = syn_ext [] [] [] ([], [], [], []) rules;
 fun syn_ext_trfuns trfuns = syn_ext [] [] [] trfuns ([], []);
 
 fun stamp_trfun s (c, f) = (c, (f, s));
 fun mk_trfun tr = stamp_trfun (stamp ()) tr;
 fun eq_trfun ((_, s1: stamp), (_, s2)) = s1 = s2;
 
 end;