Quelle  case_translation.ML   Sprache: SML

/
    inof
StefanNONE>= xsx
    Author:     Dmitriy Traytelthen x^1):   (,2 :tab

unprefix" ;
*)

signature | in ];
sig
  java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
   typ>

  datatype config =)java.lang.StringIndexOutOfBoundsException: Index 2 out of bounds for length 2
case_tr> -java.lang.StringIndexOutOfBoundsException: Index 57 out of bounds for length 57
  vallookup_by_constr
 vallookup_by_constr_permissive:Proof. ->string* typ> term*term) java.lang.StringIndexOutOfBoundsException: Range [93, 94) out of bounds for length 93
  val =ap_data(fn onstrscases >constrscases)java.lang.StringIndexOutOfBoundsException: Index 73 out of bounds for length 73
  
valrep_data=(
  val java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
  al comb
java.lang.StringIndexOutOfBoundsException: Range [3, 1) out of bounds for length 37
   term-   C- Context.java.lang.StringIndexOutOfBoundsException: Index 71 out of bounds for length 71
end;

structure Case_Translation: CASE_TRANSLATION =
struct

(** general utilities **)

funindexify_names names=    java.lang.StringIndexOutOfBoundsException: Index 4 out of bounds for length 4
  letlet
    val  (yco_= .lookup( =t
            =(  (,_= OME|  )
          NONE =>
            ifmember ( = java.lang.StringIndexOutOfBoundsException: Index 6 out of bounds for length 6
            (asehint java.lang.StringIndexOutOfBoundsException: Index 17 out of bounds for length 17
            lse  >
|SOME=(^string_of_inti): xx 1: )java.lang.StringIndexOutOfBoundsException: Index 74 out of bounds for length 74
      ex[]_ONE=(java.lang.StringIndexOutOfBoundsException: Index 40 out of bounds for length 40
  in

fun(caseAListlookup(= tab
  et
    fun java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
idx,_)) =java.lang.StringIndexOutOfBoundsException: Index 6 out of bounds for length 6
          
      
            name =.
          in if Symbol_Pos.is_identifierjava.lang.StringIndexOutOfBoundsException: Index 41 out of bounds for length 0
  in indexify_names (mapjava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0



(** data management **)

datatype        java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
          letval('used Name.variant sed
   : term* terml).table;

fun make_data (constrs, cases) = Data {constrsjava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0

structure  = Generic_Data
(
  type T = datafoldconstrain_Abs tTs( t)java.lang.StringIndexOutOfBoundsException: Index 49 out of bounds for length 49
  val    (.,Symtab)java.lang.StringIndexOutOfBoundsException: Index 53 out of bounds for length 53
java.lang.StringIndexOutOfBoundsException: Index 44 out of bounds for length 11
   canthe_constraint )(.consts)
     Data {constrsjava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
java.lang.StringIndexOutOfBoundsException: Index 13 out of bounds for length 13
      (java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
      
)  java.lang.StringIndexOutOfBoundsException: Range [29, 27) out of bounds for length 97

funabs_pat tT( usedjava.lang.StringIndexOutOfBoundsException: Index 42 out of bounds for length 42
  )=used
fun map_constrs f = map_data (              in (t' $ u', used'
fun map_cases

valrep_data=( Data |abs_pat__Ijava.lang.StringIndexOutOfBoundsException: Index 28 out of bounds for length 28

fun T_of_data funreplace_dummies( (<const_syntax\openPuredummy_pattern<close l'[]
  fastype_of               letSyntaxconst\^>opencase_elem<>$Term_Positionstrip_positionsl $r)
   end
  |> domain_type;

val Tname_of_data| dest_case1_ ( x ) used java.lang.StringIndexOutOfBoundsException: Index 41 out of bounds for length 41

val constrs_of = #constrs o rep_data;
val cases_of = caseso rep_data

fun lookup_by_constr ctxt (c, T) =
  let
    val tab=Symtab.lookup_list (java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
  java.lang.StringIndexOutOfBoundsException: Index 4 out of bounds for length 4
    (case body_type T of
      Type        yntax <^\open>ase_guard\ ,')= ';
    | _ =>          (fold_rev
  in(' ')nd

fun lookup_by_constr_permissive(dest_case2u
  let
    val            (  replace_dummiestused(,used;
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
    default=if   thenNONE else  ( (List tab)java.lang.StringIndexOutOfBoundsException: Index 72 out of bounds for length 72
    (*conservative wrt. overloaded constructors*)
  in
    (case hint of
      NONE =>val _=Theory.setupSignparse_translation[\^ (. \^const_syntax<case_elem\< T.strip_positions l' rjava.lang.StringIndexOutOfBoundsException: Index 112 out of bounds for length 112
             dest_case2( java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
        
          NONE => defaultjava.lang.StringIndexOutOfBoundsException: Range [10, 3) out of bounds for length 34
        |SOME info =>      let
  end;

val lookup_by_case = Symtab.lookup o cases_of;



(** installation **)

fun                const<const_syntax>opencase_guard<closee$t 

val name_of=try dest_Const_name;


(* parse translation *)

fun constrain_Abs tT t = Syntax.const \<^syntax_const>\<open>_constrainAbs\<close>             ( t=>fnu=>Syntax.const<const_syntax              inmk_clause t (s,T) : xs used'end

fun case_tr err ctxt [t, u] =
      let
               Syntaxconst\<syntax_const\<openase1close>java.lang.StringIndexOutOfBoundsException: Index 66 out of bounds for length 66
        fun                 map.xsrhs

        fun variant_free x
          let
   'elsex );

        fun abs p tTs t =
          .const\<^const_syntax>\opencase_abslet
            fold tTs (absfreept;

        fun abs_pat (Const (\<^syntax_const>\<open              letval Const <const_syntax\<opencase_cons\lose>,_ t $ uu)=
              abs_pat t (tT :mk_clause  ] Name. (. t)  mk_clauses java.lang.StringIndexOutOfBoundsException: Index 93 out of bounds for length 93
          | abs_pat (Free (p as (in
              if is_const x           | mk_clause (Const (<^const_syntax\opencase_elem<close>, _)   pat $ rhs) xs __ =
  abs_pat ( $u _= abs_pat u []# abs_pat t[]
          | abs_pat _ _ = I;

        (* replace occurrences of dummy_pattern by distinct variables *)
        fun replace_dummies (Const (\<^const_syntax>\<open>Pure.dummy_pattern\<close>,           foldr1(fn (t,u) = Syntax.const\<^syntax_const>\<pen_case2\close  t  u)
              letval(x,used)variant_free" used
              in (Free (x, T),      nd
          | replace_dummies (t $ u) used =
              let
                val (t' subst_bounds (map | case_tr' _ = raise Match;
                val (',used'java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
              in (t' $ u java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
            replace_dummies used=t,used

        fun dest_case1mk_clause t[ Namebuild_context (.declare_free_namest) :  
              let _ = raise Match;
                abs_patlist_comb(. \^yntax_const><>_\close>$x$
                  (Syntax. ;
              end
          | dest_case1 _ = case_error "dest_case1";

    valcase_key =dest_Const_name case_comb            mk_clauses t))
          |dest_case2t  ];

             constr_keys = mapdest_Const_nameconstrs
      
java.lang.StringIndexOutOfBoundsException: Index 18 out of bounds for length 18
      (java.lang.StringIndexOutOfBoundsException: Index 19 out of bounds for length 19
in
            (dest_case2 u)
            |>  update_cases
      end
  | case_tr _ _ _ = case_error "case_tr";

val _ = Theory.setup (Sign.parse_translation [(\<^    alcase_key =dest_Const_namecase_comb


(* print translation *)

fun case_tr' (_ :: x :: t :: ts) =
      let
        fun    valdatafn(,ts >Thmdeclaration_attributeK(t ts))
                s,vTnameT data;
              invalupdate_constrs =  ( key= . (,(, ))) 
          m ((<const_syntax\open\close,_java.lang.StringIndexOutOfBoundsException: Range [76, 75) out of bounds for length 94
              Syntax.const \<^syntax_const>\<open
                subst_bounds (map Syntax_Trans.mark_bound_absjava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
java.lang.StringIndexOutOfBoundsException: Index 2 out of bounds for length 0
          |mk_clause __  raiseMatch

|>map_cases update_cases
            ;
              mk_clause
           _= Theorysetup
      in
        list_comb         preserve namesgivenby *java.lang.StringIndexOutOfBoundsException: Index 39 out of bounds for length 39
          (fn(,u=>Syntaxconst<syntax_const\<_case2>  t$u)
            (mk_clauses t), ts)
      end
  | case_tr' _ = raise Match;

val     (Argsterm --Scanrepeat1Argsterm>


(* declarations *)

fun register raw_case_comb raw_constrs context =
  let
    valof  and;
    (
    val constrs = Variable.java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
    java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
    val constr_keys = map dest_Const_name constrs;
    val data = (case_comb, constrs);
    val Tname cjava.lang.StringIndexOutOfBoundsException: Index 12 out of bounds for length 0
 update_constrs = fnkey =Symtabcons_list( (,data)constr_keys
   . tm    )java.lang.StringIndexOutOfBoundsException: Index 60 out of bounds for length 60
  inin  constructors
    context
    | update_constrs
    |>                 ' (n(v ) ) >row |>
  end;

val _ = Theory    apfst( [(,u] > v_to_prfx)( ~~rows
(.\binding<>case_translationclose
    (Args.term -- Scan.repeat1              (Const(, cT,i =java.lang.StringIndexOutOfBoundsException: Index 44 out of bounds for length 44
( t, >Thm (K (register t ts))))
    "declaration of case combinators and constructors";


(* (Un)check phases *)|SOMEcase_comb constructors

datatype configval = cT

exceptionjava.lang.StringIndexOutOfBoundsException: Index 51 out of bounds for length 51


(*Each pattern carries with it a tag i, which denotes the clause it
  came from. i = ~1 indicates that the clause was added by pattern
  completion.*)

fun add_row_used ((prfx, pats), (tm,si(flat,tree endjava.lang.StringIndexOutOfBoundsException: Index 50 out of bounds for length 49
  old (mapfn{,, .} =java.lang.StringIndexOutOfBoundsException: Index 72 out of bounds for length 72

(*try to preserve names given by user*)
fun default_name "" (Free (name', _)) =val mk _= CASE_ERROR ((Malformedrowmatrix,)
  | default_name name _ =                        map2 (fn {new_formals, , ...}=


(*Produce an instance of a constructor, plus fresh variables for its arguments.*)
fun fresh_constr coltyused c ==
  let
    val T = dest_Const_type c;
    val Ts = binder_types T;
    val  = Name.variantsused(Absif s = "thenname , T, t))
    val ty = body_type T;
    val ty_theta = Type.raw_match (ty, colty) Vartab.empty
      handle Type.                               ~~njava.lang.StringIndexOutOfBoundsException: Range [47, 25) out of bounds for length 25
    val c' = Envir.subst_term_types ty_theta c;
    val  = mapifmemberaxsthen
  inc, = case_functions[);

(*Go through a list of rows and pick out the ones beginning with a
  pattern with constructor = name.*)
in(x :java.lang.StringIndexOutOfBoundsException: Range [20, 19) out of bounds for length 21
  let val k =   _ )pat]java.lang.StringIndexOutOfBoundsException: Range [22, 21) out of bounds for length 21
prfx ::psrhs ,i))=
      fn ((in_group, not_in_group)inmk end
        java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
           name _java.lang.StringIndexOutOfBoundsException: Range [33, 30) out of bounds for length 37
            t_varsctxt pat  fold_aterms
              if length args         Termf    (, )java.lang.StringIndexOutOfBoundsException: Index 25 out of bounds for length 25
                ((((          ( s "occurs repeatedly java.lang.StringIndexOutOfBoundsException: Range [70, 71) out of bounds for length 70
                 map2 default_name
                  val  = map(no_repeat_vars             Syntaxstring_of_term  pat)java.lang.StringIndexOutOfBoundsException: Index 51 out of bounds for length 51
             (n_group row:not_in_group), names)
        | _ => raise CASE_ERROR ("
    rows ([], []), replicate[),replicate k ") valrangeT java.lang.StringIndexOutOfBoundsException: Range [17, 16) out of bounds for length 16
  ;


(* Partitioning *)

fun partition _ _ _ _ [] = raise CASE_ERROR ("partition: no rows", ~1)
  |Term(. \^>_\close,
      let
        fun part          Syntax.  ,rhs
 =  " acpattern" java.lang.StringIndexOutOfBoundsException: Index 90 out of bounds for length 90
          | part (c ::     rangeT =
              let
                val ((in_group, (case distinct (op =) (map (fastype_ofmsg, i =>
                val used' = fold add_row_used in_group used;
                val|_= case_errorallmusthave the same result type          case_error
                 in_group'
                  if null in_group  (* Constructor not given *)
                  then
                    let
v Tsfastype_of ps
                      valcase_error
                        Name. fold Termdeclare_free_namesgvarsused)
                          (replicate (length ps) "x");
                    
                      [((prfx, gvars              Thefollowing clausesareby clauses: 
open<,),1)java.lang.StringIndexOutOfBoundsException: Index 86 out of bounds for length 86
          if          
                  else in_group;
(* term check *)
                constructor  'java.lang.StringIndexOutOfBoundsException: Index 34 out of bounds for length 34
                 ew_formals ,
                 names = names,

              end
      in   end

 i t( s   xse
  | v_to_prfx _ = raise CASE_ERROR ("mk_case: v_to_prfx", ~1);


(* Translation of pattern terms into nested case expressions. *) decode_clause  Frees, T:xs used java.lang.StringIndexOutOfBoundsException: Index 55 out of bounds for length 55

fun mk_case ctxt used range_ty =
l
    val java.lang.StringIndexOutOfBoundsException: Index 12 out of bounds for length 0

    fun expand _ _ _ ((_, []), _) = raise CASE_ERROR ("mk_case: expand", ~1)
ps java.lang.StringIndexOutOfBoundsException: Range [67, 66) out of bounds for length 76
                    if ](ame(.declare_free_names   u
            let
              val used' =
              fun expnd c =
                let val capp java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
                 ( ::pssubst_free [p,) rhs, tag end
             ctxt if. u( java.lang.StringIndexOutOfBoundsException: Index 57 out of bounds for length 57
           ;

    val (nameletval(  ( )decode_case   u

    fun  |decode_case( asAbs)  t
  (_ ),):)(]  java.lang.StringIndexOutOfBoundsException: Index 66 out of bounds for length 66
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
      |mku:java.lang.StringIndexOutOfBoundsException: Index 6 out of bounds for length 6
          let val col0 = map (fn
            (case ( apfstname_of( ))f
              
                let
                  val rowsjava.lang.StringIndexOutOfBoundsException: Index 6 out of bounds for length 0
java.lang.StringIndexOutOfBoundsException: Range [11, 8) out of bounds for length 27
                valstrip_abs_vars
            |  (Const            | SOME (Const
                (case v fs ysjava.lang.StringIndexOutOfBoundsException: Index 26 out of bounds for length 26
                   ap( java.lang.StringIndexOutOfBoundsException: Index 13 out of bounds for length 13
                | SOME (case_comb, 
                    letvalu=fold_revTermabs  strip_abs_body t)java.lang.StringIndexOutOfBoundsException: Index 60 out of bounds for length 60
                      val pty = body_type cT;
                       ' Tdeclare_free_names us;
                      val nrows = maps (expand constructors used' pty) val = fold_rev Term.abs ys strip_abs_body t);
 subproblems= partition usedconstructors ptyrange_ty
                      val (pat_rect, dtrees) =
                        split_list (map (fn {new_formals, group,letval  = length sjava.lang.StringIndexOutOfBoundsException: Range [15, 13) out of bounds for length 39
                          mk (new_formals @ us) group) subproblems);
                      valcase_functions 
                         ( ,body,falseAListmap_defaultop,(ons)
d_rev xas(),s=t>
                            Abs (if s = "" then name else s, T, abstract_over (x, t)))
                              ~names)
                        subproblems dtrees;
                         fastype_of case_functions@  [[];
                      val case_const = Const (name_of case_comb |> the        fun count_cases
                      val   list_comb(,  @ []java.lang.StringIndexOutOfBoundsException: Index 78 out of bounds for length 78
                    inflat pat_rect  end
            funmk_case(,java.lang.StringIndexOutOfBoundsException: Index 24 out of bounds for length 17
                raiseCASE_ERROR(Notadatatype "^ Syntaxstring_of_term ctxt
          end
      |  __=( )=java.lang.StringIndexOutOfBoundsException: Index 35 out of bounds for length 35
  in ;


(*Repeated variable occurrences in a pattern are not allowed.*)
fun  = fold_aterms
  (fn x as Free (s, _) =>
      ( xs=java.lang.StringIndexOutOfBoundsException: Index 15 out of bounds for length 15
        f    x 
          case_error (quote s ^ " occurs repeatedly in the pattern " ^
string_of_termrm ctxt ))
        else x :: xs)
_= )pat [java.lang.StringIndexOutOfBoundsException: Range [19, 16) out of bounds for length 28

 make_case ctxtconfigusedxclauses=
  let
    fun string_of_clause (pat, rhs) =
      Syntax.unparse_term ctxt
syntax_const>\open_close,
          Syntax.uncheck_terms ctxt [pat, rhs])( count_casescases [);
      |> Pretty.string_of;

java.lang.StringIndexOutOfBoundsException: Range [7, 4) out of bounds for length 52
    val rows = map_index                     Namevariantjava.lang.StringIndexOutOfBoundsException: Index 16 out of bounds for length 16
      =
      (case distinctop=)map( o       (case distinct (op =) (map (fastype_of o snd) clauses
        [] => case_error "no(casejava.lang.StringIndexOutOfBoundsException: Range [34, 33) out of bounds for length 74
java.lang.StringIndexOutOfBoundsException: Index 24 out of bounds for length 16
      | _ => case_error "all cases =java.lang.StringIndexOutOfBoundsException: Range [45, 39) out of bounds for length 74
    val' == add_row_usedrows ;
    val (tags, case_tm) =
       ctxt' [xcase cases
        handle |default ):                         cs: =
          case_error
            (msg ^ (if i                            else if                             iflength cs=   java.lang.StringIndexOutOfBoundsException: Index 72 out of bounds for length 72
    val _ =
      (case subtract (op =) tagsend
        [= )
      | is =>
          if config = Quiet then ()
          java.lang.StringIndexOutOfBoundsException: Index 14 out of bounds for length 14
 then case_errorelse warning (*FIXME lack of syntactic context!?*))
              ("java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
cat_lines     \\opencase_abscloseU -T ->T  .  end)
  in
    letval(.  [java.lang.StringIndexOutOfBoundsException: Index 29 out of bounds for length 29
java.lang.StringIndexOutOfBoundsException: Index 6 out of bounds for length 6


(* term check *)

fun (C(^><case_consclose  - )- S- ) > ->)$
l  s,java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
in  Free recurjava.lang.StringIndexOutOfBoundsException: Range [28, 27) out of bounds for length 38
  | decode_clause (Const (\<^const_name>\<open>case_elem\< <java.lang.StringIndexOutOfBoundsException: Range [27, 26) out of bounds for length 91
      (subst_bounds (xs, t)      in
  | decode_clause _ _ _        Const \<^const_name> encode_clauserecurT p $encode_casesrecurS T ps;

fun           <^term\<java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
  |decode_cases
       
  | decode_cases

fun check_case ctxt case  d Namebuild_context Termdeclare_free_names pat)rhs 
  let
      ( (<onst_name\>\close,)   $   =
          make_case ctxt (if\      Term( (p )exp)  java.lang.StringIndexOutOfBoundsException: Index 63 out of bounds for length 63
            Name.context      
      |java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
      | decode_case (  case dest_case   Namebuild_context (.declare_free_names          ubst_freeexp' patrhs)))
          let val (v, t') = Term.dest_abs_global
           ermabsfree v (ecode_case 'java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
        tSx )>SOMEx,mapsstrip_case ctxt )
  in
    java.lang.StringIndexOutOfBoundsException: Index 19 out of bounds for length 19
  endrip_case_full t=

  (casedest_case ctxt


(* Pretty printing of nested case expressions *) ('ctxt d) ( (fn pat', hsjava.lang.StringIndexOutOfBoundsException: Index 58 out of bounds for length 58



fun dest_case(dest_casectxtNamecontextt java.lang.StringIndexOutOfBoundsException: Index 42 out of bounds for length 42
  ( apfstname_of ( )java.lang.StringIndexOutOfBoundsException: Index 39 out of bounds for length 39
     d  =
      let
a (,let(). java.lang.StringIndexOutOfBoundsException: Index 51 out of bounds for length 51
        fun strip_abs i t =
          let
              = strip_abs_vars
            val j = length zs;
            java.lang.StringIndexOutOfBoundsException: Range [16, 15) out of bounds for length 26
              if   thenzs @
                map (pair "x")|  _ >
               t=
            valinTerm .getctxtshow_cases
            xs' mapFree(Name.variant_names(Term.declare_free_names u used) ;
            val (xs1, xs2) =  java.lang.StringIndexOutOfBoundsException: Index 18 out of bounds for length 18
xs1 u)x) java.lang.StringIndexOutOfBoundsException: Index 67 out of bounds for length 67
        funis_dependent
          let k=length( )-
          in>can   strip_case_full ctxt  java.lang.StringIndexOutOfBoundsException: Range [79, 0) out of bounds for length 0
 _,java.lang.StringIndexOutOfBoundsException: Range [35, 32) out of bounds for length 40
|count_cases(,(,body,java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
        funval=. java.lang.StringIndexOutOfBoundsException: Index 46 out of bounds for length 46
        fun mk_case (c,          java.lang.StringIndexOutOfBoundsException: Index 9 out of bounds for length 9
        val get_info = lookup_by_case ctxt;
      in
        (case get_info cname of
          OME(_ ) =>
            if length fs = length constructors then
              let
                val R = fastype_of x;
                val cases = map (fn (Const (s, U), t) =>
                  let
                    Us= binder_types U;
                    val k = length Us;
                    val p as (xs, _) = strip_abs k t;
                  java.lang.StringIndexOutOfBoundsException: Index 20 out of bounds for length 20
                    (           [Pretty       xname externtype_space name;
                  end) (constructors ~~ fs);
                val cases' =
                  sort (int_ord         markup =Name_Space name
                   java.lang.StringIndexOutOfBoundsException: Range [30, 29) out of bounds for length 52
                val dummy =
                  thenTermR
                  else Free (Name.variant "x"           . Pretty(,xname Prettystr"",
              java.lang.StringIndexOutOfBoundsException: Index 16 out of bounds for length 16
                SOME (x,
                  map              Prettycommas(  ));
                    (case find_first (is_undefined o fst) cases' of
                      SOME (_, cs) =>
                        if length cs = length constructors then [hd cases]
                        else filter_out java.lang.StringIndexOutOfBoundsException: Index 86 out of bounds for length 86
|NONE
                        (case  end
                          [] => cases
                        | (default,  Outer_Syntax.command \end;
                            if length cs = 1 then cases
                             iflengthcs lengthconstructorsthen
                              [hd cases, (dummy, ([], default),    Scan.ucceed(Toplevel. ( o Toplevel.))))
                            elseendjava.lang.StringIndexOutOfBoundsException: Index 4 out of bounds for length 4
                              filter_out (fn (c, _, _) => member op aconv cs c) cases @
                                [(dummy, ([], default), false)])))
              end
            else NONE
        | _ => NONE)
      end
  | _ => NONE);


(* destruct nested patterns *)

fun encode_clause recur S T (pat, rhs) =
  fold (fn x as (_, U) => fn t =>
    let val T = fastype_of t;
    in Const (\<^const_name>\<open>case_abs\<close>, (U --> T) --> T) $ Term.absfree x t end)
      (Term.add_frees pat [])
      (Const (\<^const_name>\<open>case_elem\<close>, S --> T --> S --> T) $ pat $ recur rhs);

fun encode_cases _ S T [] = Const (\<^const_name>\<open>case_nil\<close>, S --> T)
  | encode_cases recur S T (p :: ps) =
      Const (\<^const_name>\<open>case_cons\<close>, (S --> T) --> (S --> T) --> S --> T) $
        encode_clause recur S T p $ encode_cases recur S T ps;

fun encode_case recur (t, ps as (pat, rhs) :: _) =
      let
        val tT = fastype_of t;
        val T = fastype_of rhs;
      in
        Const (\<^const_name>\<open>case_guard\<close>, \<^typ>\<open>bool\<close> --> tT --> (tT --> T) --> T) $
          \<^term>\<open>True\<close> $ t $ (encode_cases recur (fastype_of pat) (fastype_of rhs) ps)
      end
  | encode_case _ _ = case_error "encode_case";

fun strip_case' ctxt d (pat, rhs) =
  (case dest_case ctxt d (Name.build_context (Term.declare_free_names pat)) rhs of
    SOME (exp as Free _, clauses) =>
      if Term.exists_subterm (curry (op aconv) exp) pat andalso
        not (exists (fn (_, rhs') =>
          Term.exists_subterm (curry (op aconv) exp) rhs') clauses)
      then
        maps (strip_case' ctxt d) (map (fn (pat', rhs') =>
          (subst_free [(exp, pat')] pat, rhs')) clauses)
      else [(pat, rhs)]
  | _ => [(pat, rhs)]);

fun strip_case ctxt d t =
  (case dest_case ctxt d Name.context t of
    SOME (x, clauses) => SOME (x, maps (strip_case' ctxt d) clauses)
  | NONE => NONE);

fun strip_case_full ctxt d t =
  (case dest_case ctxt d Name.context t of
    SOME (x, clauses) =>
      encode_case (strip_case_full ctxt d)
        (strip_case_full ctxt d x, maps (strip_case' ctxt d) clauses)
  | NONE =>
      (case t of
        t $ u => strip_case_full ctxt d t $ strip_case_full ctxt d u
      | Abs _ =>
          let val (v, t') = Term.dest_abs_global t;
          in Term.absfree v (strip_case_full ctxt d t') end
      | _ => t));


(* term uncheck *)

val show_cases = Attrib.setup_config_bool \<^binding>\<open>show_cases\<close> (K true);

fun uncheck_case ctxt ts =
  if Config.get ctxt show_cases
  then map (fn t => if can Term.type_of t then strip_case_full ctxt true t else t) ts
  else ts;

val _ = Context.>> (Syntax_Phases.term_uncheck 1 "case" uncheck_case);


(* outer syntax commands *)

fun print_case_translations ctxt =
  let
    val cases = map snd (Symtab.dest (cases_of ctxt));
    val type_space = Proof_Context.type_space ctxt;

    val pretty_term = Syntax.pretty_term ctxt;

    fun pretty_data (data as (comb, ctrs)) =
      let
        val name = Tname_of_data data;
        val xname = Name_Space.extern ctxt type_space name;
        val markup = Name_Space.markup type_space name;
        val prt =
          (Pretty.block o Pretty.fbreaks)
           [Pretty.block [Pretty.mark_str (markup, xname), Pretty.str ":"],
            Pretty.block [Pretty.str "combinator:", Pretty.brk 1, pretty_term comb],
            Pretty.block (Pretty.str "constructors:" :: Pretty.brk 1 ::
              Pretty.commas (map pretty_term ctrs))];
      in (xname, prt) end;
  in
    Pretty.big_list "case translations:" (map #2 (sort_by #1 (map pretty_data cases)))
    |> Pretty.writeln
  end;

val _ =
  Outer_Syntax.command \<^command_keyword>\<open>print_case_translations\<close>
    "print registered case combinators and constructors"
    (Scan.succeed (Toplevel.keep (print_case_translations o Toplevel.context_of)))

end;