--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Nominal/nominal_basics.ML	Mon Feb 28 15:21:10 2011 +0000
@@ -0,0 +1,152 @@
+(*  Title:      nominal_basic.ML
+    Author:     Christian Urban
+
+  Basic functions for nominal.
+*)
+
+signature NOMINAL_BASIC =
+sig
+  val trace: bool Unsynchronized.ref
+  val trace_msg: (unit -> string) -> unit
+
+  val last2: 'a list -> 'a * 'a
+  val split_last2: 'a list -> 'a list * 'a * 'a
+  val order: ('a * 'a -> bool) -> 'a list -> ('a * 'b) list -> 'b list
+  val order_default: ('a * 'a -> bool) -> 'b -> 'a list -> ('a * 'b) list -> 'b list
+  val remove_dups: ('a * 'a -> bool) -> 'a list -> 'a list
+  val map4: ('a -> 'b -> 'c -> 'd -> 'e) -> 'a list -> 'b list -> 'c list -> 'd list -> 'e list
+  val split_filter: ('a -> bool) -> 'a list -> 'a list * 'a list
+  val fold_left: ('a * 'a -> 'a) -> 'a list -> 'a -> 'a
+  
+  val is_true: term -> bool
+ 
+  val dest_listT: typ -> typ
+  val dest_fsetT: typ -> typ
+
+  val mk_id: term -> term
+  val mk_all: (string * typ) -> term -> term
+  val mk_All: (string * typ) -> term -> term
+  val mk_exists: (string * typ) -> term -> term
+
+  val sum_case_const: typ -> typ -> typ -> term
+  val mk_sum_case: term -> term -> term
+ 
+  val mk_equiv: thm -> thm
+  val safe_mk_equiv: thm -> thm
+
+  val mk_minus: term -> term
+  val mk_plus: term -> term -> term
+
+  val perm_ty: typ -> typ 
+  val perm_const: typ -> term
+  val mk_perm_ty: typ -> term -> term -> term
+  val mk_perm: term -> term -> term
+  val dest_perm: term -> term * term
+
+end
+
+
+structure Nominal_Basic: NOMINAL_BASIC =
+struct
+
+val trace = Unsynchronized.ref false
+fun trace_msg msg = if ! trace then tracing (msg ()) else ()
+
+
+(* orders an AList according to keys - every key needs to be there *)
+fun order eq keys list = 
+  map (the o AList.lookup eq list) keys
+
+(* orders an AList according to keys - returns default for non-existing keys *)
+fun order_default eq default keys list = 
+  map (the_default default o AList.lookup eq list) keys
+
+(* remove duplicates *)
+fun remove_dups eq [] = []
+  | remove_dups eq (x :: xs) = 
+      if member eq xs x 
+      then remove_dups eq xs 
+      else x :: remove_dups eq xs
+
+fun last2 [] = raise Empty
+  | last2 [_] = raise Empty
+  | last2 [x, y] = (x, y)
+  | last2 (_ :: xs) = last2 xs
+
+fun split_last2 xs = 
+  let
+    val (xs', x) = split_last xs
+    val (xs'', y) = split_last xs'
+  in
+    (xs'', y, x)
+  end
+
+fun map4 _ [] [] [] [] = []
+  | map4 f (x :: xs) (y :: ys) (z :: zs) (u :: us) = f x y z u :: map4 f xs ys zs us
+
+fun split_filter f [] = ([], [])
+  | split_filter f (x :: xs) =
+      let 
+        val (r, l) = split_filter f xs 
+      in 
+        if f x 
+        then (x :: r, l) 
+        else (r, x :: l) 
+      end
+
+(* to be used with left-infix binop-operations *)
+fun fold_left f [] z = z
+  | fold_left f [x] z = x
+  | fold_left f (x :: y :: xs) z = fold_left f (f (x, y) :: xs) z
+
+
+
+fun is_true @{term "Trueprop True"} = true
+  | is_true _ = false 
+
+fun dest_listT (Type (@{type_name list}, [T])) = T
+  | dest_listT T = raise TYPE ("dest_listT: list type expected", [T], [])
+
+fun dest_fsetT (Type (@{type_name fset}, [T])) = T
+  | dest_fsetT T = raise TYPE ("dest_fsetT: fset type expected", [T], []);
+
+
+fun mk_id trm = HOLogic.id_const (fastype_of trm) $ trm
+
+fun mk_all (a, T) t =  Term.all T $ Abs (a, T, t)
+
+fun mk_All (a, T) t =  HOLogic.all_const T $ Abs (a, T, t)
+
+fun mk_exists (a, T) t =  HOLogic.exists_const T $ Abs (a, T, t)
+
+fun sum_case_const ty1 ty2 ty3 = 
+  Const (@{const_name sum_case}, [ty1 --> ty3, ty2 --> ty3, Type (@{type_name sum}, [ty1, ty2])] ---> ty3)
+
+fun mk_sum_case trm1 trm2 =
+  let
+    val ([ty1], ty3) = strip_type (fastype_of trm1)
+    val ty2 = domain_type (fastype_of trm2)
+  in
+    sum_case_const ty1 ty2 ty3 $ trm1 $ trm2
+  end 
+
+
+fun mk_equiv r = r RS @{thm eq_reflection};
+fun safe_mk_equiv r = mk_equiv r handle Thm.THM _ => r;
+
+
+fun mk_minus p = @{term "uminus::perm => perm"} $ p
+
+fun mk_plus p q = @{term "plus::perm => perm => perm"} $ p $ q
+
+fun perm_ty ty = @{typ "perm"} --> ty --> ty
+fun perm_const ty  = Const (@{const_name "permute"}, perm_ty ty)
+fun mk_perm_ty ty p trm = perm_const ty $ p $ trm
+fun mk_perm p trm = mk_perm_ty (fastype_of trm) p trm
+
+fun dest_perm (Const (@{const_name "permute"}, _) $ p $ t) = (p, t)
+  | dest_perm t = raise TERM ("dest_perm", [t]);
+
+end (* structure *)
+
+open Nominal_Basic;
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