More OPA conformant semantics (#62)

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

src/builtins/sets.rs

@@ -34,7 +34,12 @@ pub fn difference(expr1: &Expr, expr2: &Expr, v1: Value, v2: Value) -> Result<Va
     Ok(Value::from_set(s1.difference(&s2).cloned().collect()))
 }
 
-fn intersection_of_set_of_sets(span: &Span, params: &[Ref<Expr>], args: &[Value]) -> Result<Value> {
+fn intersection_of_set_of_sets(
+    span: &Span,
+    params: &[Ref<Expr>],
+    args: &[Value],
+    _strict: bool,
+) -> Result<Value> {
     let name = "intersection";
     ensure_args_count(span, name, params, args, 1)?;
     let set = ensure_set(name, &params[0], args[0].clone())?;
@@ -61,7 +66,12 @@ fn intersection_of_set_of_sets(span: &Span, params: &[Ref<Expr>], args: &[Value]
     Ok(Value::from_set(res))
 }
 
-fn union_of_set_of_sets(span: &Span, params: &[Ref<Expr>], args: &[Value]) -> Result<Value> {
+fn union_of_set_of_sets(
+    span: &Span,
+    params: &[Ref<Expr>],
+    args: &[Value],
+    _strict: bool,
+) -> Result<Value> {
     let name = "union";
     ensure_args_count(span, name, params, args, 1)?;
     let set = ensure_set(name, &params[0], args[0].clone())?;