     { att-defs string } ;
 C: <attlist-decl> attlist-decl
 
-UNION: boolean t POSTPONE: f ;
-
 TUPLE: entity-decl < directive
     { name string }
     { def string }

    { parameter-entities assoc } ;
C: <dtd> dtd

UNION: dtd/f dtd POSTPONE: f ;

TUPLE: doctype-decl < directive
    { name string }
    { external-id id }
    { internal-subset dtd/f } ;
C: <doctype-decl> doctype-decl

TUPLE: notation-decl < directive

TUPLE: interpolated var ;
C: <interpolated> interpolated

TUPLE: name
    { space maybe{ string } }
    { main string }
    { url maybe{ string } } ;
C: <name> name

: ?= ( object/f object/f -- ? )
