add overloads for finite sets

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/api/python/z3/z3.py

@@ -5050,6 +5050,8 @@ def EmptySet(s):
     K(Int, False)
     """
     ctx = s.ctx
+    if is_finite_set_sort(s):
+        return FiniteSetEmpty(s)
     return ArrayRef(Z3_mk_empty_set(ctx.ref(), s.ast), ctx)
 
 
@@ -5070,6 +5072,9 @@ def SetUnion(*args):
     union(a, b)
     """
     args = _get_args(args)
+    if len(args) > 0 and is_finite_set(args[0]):
+        from functools import reduce
+        return reduce(FiniteSetUnion, args)
     ctx = _ctx_from_ast_arg_list(args)
     _args, sz = _to_ast_array(args)
     return ArrayRef(Z3_mk_set_union(ctx.ref(), sz, _args), ctx)
@@ -5084,6 +5089,9 @@ def SetIntersect(*args):
     """
     args = _get_args(args)
     ctx = _ctx_from_ast_arg_list(args)
+    if len(args) > 0 and is_finite_set(args[0]):
+        from functools import reduce
+        return reduce(FiniteSetIntersect, args)
     _args, sz = _to_ast_array(args)
     return ArrayRef(Z3_mk_set_intersect(ctx.ref(), sz, _args), ctx)
 
@@ -5096,6 +5104,8 @@ def SetAdd(s, e):
     """
     ctx = _ctx_from_ast_arg_list([s, e])    
     e = _py2expr(e, ctx)
+    if is_finite_set(s):
+        return FiniteSetSingleton(e) | s             
     return ArrayRef(Z3_mk_set_add(ctx.ref(), s.as_ast(), e.as_ast()), ctx)
 
 
@@ -5107,6 +5117,8 @@ def SetDel(s, e):
     """
     ctx = _ctx_from_ast_arg_list([s, e])
     e = _py2expr(e, ctx)
+    if is_finite_set(s):
+        return s - FiniteSetSingleton(e)
     return ArrayRef(Z3_mk_set_del(ctx.ref(), s.as_ast(), e.as_ast()), ctx)
 
 
@@ -5128,6 +5140,8 @@ def SetDifference(a, b):
     setminus(a, b)
     """
     ctx = _ctx_from_ast_arg_list([a, b])
+    if is_finite_set(a):
+        return FiniteSetDifference(a, b)
     return ArrayRef(Z3_mk_set_difference(ctx.ref(), a.as_ast(), b.as_ast()), ctx)
 
 
@@ -5139,6 +5153,8 @@ def IsMember(e, s):
     """
     ctx = _ctx_from_ast_arg_list([s, e])
     e = _py2expr(e, ctx)
+    if is_finite_set(s):
+        return FiniteSetIsMember(e, s)
     return BoolRef(Z3_mk_set_member(ctx.ref(), e.as_ast(), s.as_ast()), ctx)
 
 
@@ -5150,6 +5166,8 @@ def IsSubset(a, b):
     subset(a, b)
     """
     ctx = _ctx_from_ast_arg_list([a, b])
+    if is_finite_set(a):
+        return FiniteSetIsSubset(a, b)
     return BoolRef(Z3_mk_set_subset(ctx.ref(), a.as_ast(), b.as_ast()), ctx)
 
 
@@ -5178,7 +5196,7 @@ class FiniteSetSortRef(SortRef):
             elem_sort = self.element_sort()
             result = FiniteSetEmpty(self)
             for e in val:
-                result = FiniteSetUnion(result, FiniteSetSingleton(_py2expr(e, self.ctx, elem_sort)))
+                result = FiniteSetUnion(result, Singleton(_py2expr(e, self.ctx, elem_sort)))
             return result
         _z3_assert(False, "Cannot cast to finite set sort")
 
@@ -5260,9 +5278,9 @@ def FiniteSetEmpty(set_sort):
     return FiniteSetRef(Z3_mk_finite_set_empty(ctx.ref(), set_sort.ast), ctx)
 
 
-def FiniteSetSingleton(elem):
+def Singleton(elem):
     """Create a singleton finite set containing elem.
-    >>> FiniteSetSingleton(IntVal(1))
+    >>> Singleton(IntVal(1))
     set.singleton(1)
     """
     ctx = elem.ctx
@@ -5311,6 +5329,8 @@ def FiniteSetMember(elem, set):
     ctx = _ctx_from_ast_arg_list([elem, set])
     return BoolRef(Z3_mk_finite_set_member(ctx.ref(), elem.as_ast(), set.as_ast()), ctx)
 
+def In(elem, set):
+    return FiniteSetMember(elem, set)
 
 def FiniteSetSize(set):
     """Get the size (cardinality) of a finite set.
@@ -11726,6 +11746,14 @@ def Union(*args):
     sz = len(args)
     if z3_debug():
         _z3_assert(sz > 0, "At least one argument expected.")
+    arg0 = args[0]
+    if is_finite_set(arg0):
+        for a in args[1:]:
+            if not is_finite_set(a):
+                raise Z3Exception("All arguments must be regular expressions or finite sets.")
+            arg0 = arg0 | a
+        return arg0
+    if z3_debug():
         _z3_assert(all([is_re(a) for a in args]), "All arguments must be regular expressions.")
     if sz == 1:
         return args[0]
@@ -11744,6 +11772,14 @@ def Intersect(*args):
     sz = len(args)
     if z3_debug():
         _z3_assert(sz > 0, "At least one argument expected.")
+    arg0 = args[0]
+    if is_finite_set(arg0):
+        for a in args[1:]:
+            if not is_finite_set(a):
+                raise Z3Exception("All arguments must be regular expressions or finite sets.")
+            arg0 = arg0 & a
+        return arg0
+    if z3_debug():
         _z3_assert(all([is_re(a) for a in args]), "All arguments must be regular expressions.")
     if sz == 1:
         return args[0]