Nominal/nominal_basics.ML
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     1 (*  Title:      nominal_basic.ML
       
     2     Author:     Christian Urban
       
     3 
       
     4   Basic functions for nominal.
       
     5 *)
       
     6 
       
     7 signature NOMINAL_BASIC =
       
     8 sig
       
     9   val trace: bool Unsynchronized.ref
       
    10   val trace_msg: (unit -> string) -> unit
       
    11 
       
    12   val last2: 'a list -> 'a * 'a
       
    13   val split_last2: 'a list -> 'a list * 'a * 'a
       
    14   val order: ('a * 'a -> bool) -> 'a list -> ('a * 'b) list -> 'b list
       
    15   val order_default: ('a * 'a -> bool) -> 'b -> 'a list -> ('a * 'b) list -> 'b list
       
    16   val remove_dups: ('a * 'a -> bool) -> 'a list -> 'a list
       
    17   val map4: ('a -> 'b -> 'c -> 'd -> 'e) -> 'a list -> 'b list -> 'c list -> 'd list -> 'e list
       
    18   val split_filter: ('a -> bool) -> 'a list -> 'a list * 'a list
       
    19   val fold_left: ('a * 'a -> 'a) -> 'a list -> 'a -> 'a
       
    20   
       
    21   val is_true: term -> bool
       
    22  
       
    23   val dest_listT: typ -> typ
       
    24   val dest_fsetT: typ -> typ
       
    25 
       
    26   val mk_id: term -> term
       
    27   val mk_all: (string * typ) -> term -> term
       
    28   val mk_All: (string * typ) -> term -> term
       
    29   val mk_exists: (string * typ) -> term -> term
       
    30 
       
    31   val sum_case_const: typ -> typ -> typ -> term
       
    32   val mk_sum_case: term -> term -> term
       
    33  
       
    34   val mk_equiv: thm -> thm
       
    35   val safe_mk_equiv: thm -> thm
       
    36 
       
    37   val mk_minus: term -> term
       
    38   val mk_plus: term -> term -> term
       
    39 
       
    40   val perm_ty: typ -> typ 
       
    41   val perm_const: typ -> term
       
    42   val mk_perm_ty: typ -> term -> term -> term
       
    43   val mk_perm: term -> term -> term
       
    44   val dest_perm: term -> term * term
       
    45 
       
    46 end
       
    47 
       
    48 
       
    49 structure Nominal_Basic: NOMINAL_BASIC =
       
    50 struct
       
    51 
       
    52 val trace = Unsynchronized.ref false
       
    53 fun trace_msg msg = if ! trace then tracing (msg ()) else ()
       
    54 
       
    55 
       
    56 (* orders an AList according to keys - every key needs to be there *)
       
    57 fun order eq keys list = 
       
    58   map (the o AList.lookup eq list) keys
       
    59 
       
    60 (* orders an AList according to keys - returns default for non-existing keys *)
       
    61 fun order_default eq default keys list = 
       
    62   map (the_default default o AList.lookup eq list) keys
       
    63 
       
    64 (* remove duplicates *)
       
    65 fun remove_dups eq [] = []
       
    66   | remove_dups eq (x :: xs) = 
       
    67       if member eq xs x 
       
    68       then remove_dups eq xs 
       
    69       else x :: remove_dups eq xs
       
    70 
       
    71 fun last2 [] = raise Empty
       
    72   | last2 [_] = raise Empty
       
    73   | last2 [x, y] = (x, y)
       
    74   | last2 (_ :: xs) = last2 xs
       
    75 
       
    76 fun split_last2 xs = 
       
    77   let
       
    78     val (xs', x) = split_last xs
       
    79     val (xs'', y) = split_last xs'
       
    80   in
       
    81     (xs'', y, x)
       
    82   end
       
    83 
       
    84 fun map4 _ [] [] [] [] = []
       
    85   | map4 f (x :: xs) (y :: ys) (z :: zs) (u :: us) = f x y z u :: map4 f xs ys zs us
       
    86 
       
    87 fun split_filter f [] = ([], [])
       
    88   | split_filter f (x :: xs) =
       
    89       let 
       
    90         val (r, l) = split_filter f xs 
       
    91       in 
       
    92         if f x 
       
    93         then (x :: r, l) 
       
    94         else (r, x :: l) 
       
    95       end
       
    96 
       
    97 (* to be used with left-infix binop-operations *)
       
    98 fun fold_left f [] z = z
       
    99   | fold_left f [x] z = x
       
   100   | fold_left f (x :: y :: xs) z = fold_left f (f (x, y) :: xs) z
       
   101 
       
   102 
       
   103 
       
   104 fun is_true @{term "Trueprop True"} = true
       
   105   | is_true _ = false 
       
   106 
       
   107 fun dest_listT (Type (@{type_name list}, [T])) = T
       
   108   | dest_listT T = raise TYPE ("dest_listT: list type expected", [T], [])
       
   109 
       
   110 fun dest_fsetT (Type (@{type_name fset}, [T])) = T
       
   111   | dest_fsetT T = raise TYPE ("dest_fsetT: fset type expected", [T], []);
       
   112 
       
   113 
       
   114 fun mk_id trm = HOLogic.id_const (fastype_of trm) $ trm
       
   115 
       
   116 fun mk_all (a, T) t =  Term.all T $ Abs (a, T, t)
       
   117 
       
   118 fun mk_All (a, T) t =  HOLogic.all_const T $ Abs (a, T, t)
       
   119 
       
   120 fun mk_exists (a, T) t =  HOLogic.exists_const T $ Abs (a, T, t)
       
   121 
       
   122 fun sum_case_const ty1 ty2 ty3 = 
       
   123   Const (@{const_name sum_case}, [ty1 --> ty3, ty2 --> ty3, Type (@{type_name sum}, [ty1, ty2])] ---> ty3)
       
   124 
       
   125 fun mk_sum_case trm1 trm2 =
       
   126   let
       
   127     val ([ty1], ty3) = strip_type (fastype_of trm1)
       
   128     val ty2 = domain_type (fastype_of trm2)
       
   129   in
       
   130     sum_case_const ty1 ty2 ty3 $ trm1 $ trm2
       
   131   end 
       
   132 
       
   133 
       
   134 fun mk_equiv r = r RS @{thm eq_reflection};
       
   135 fun safe_mk_equiv r = mk_equiv r handle Thm.THM _ => r;
       
   136 
       
   137 
       
   138 fun mk_minus p = @{term "uminus::perm => perm"} $ p
       
   139 
       
   140 fun mk_plus p q = @{term "plus::perm => perm => perm"} $ p $ q
       
   141 
       
   142 fun perm_ty ty = @{typ "perm"} --> ty --> ty
       
   143 fun perm_const ty  = Const (@{const_name "permute"}, perm_ty ty)
       
   144 fun mk_perm_ty ty p trm = perm_const ty $ p $ trm
       
   145 fun mk_perm p trm = mk_perm_ty (fastype_of trm) p trm
       
   146 
       
   147 fun dest_perm (Const (@{const_name "permute"}, _) $ p $ t) = (p, t)
       
   148   | dest_perm t = raise TERM ("dest_perm", [t]);
       
   149 
       
   150 end (* structure *)
       
   151 
       
   152 open Nominal_Basic;