move BinOp to top level

conjure_oxide/src/parse.rs

@@ -133,9 +133,10 @@ fn parse_int_domain(v: &JsonValue) -> Result<Domain> {
  Ok(Domain::IntDomain(ranges))
 }
 
+// this needs an explicit type signature to force the closures to have the same type
+type BinOp = Box<dyn Fn(Box<Expression>, Box<Expression>) -> Expression>;
+
 fn parse_expression(obj: &JsonValue) -> Option<Expression> {
- // this needs an explicit type signature to force the closures to have the same type
- type BinOp = Box<dyn Fn(Box<Expression>, Box<Expression>) -> Expression>;
  let binary_operators: HashMap<&str, BinOp> = [
  ("MkOpEq", Box::new(Expression::Eq) as Box<dyn Fn(_, _) -> _>),
  (
@@ -187,7 +188,7 @@ fn parse_sum(op_sum: &serde_json::Map<String, Value>) -> Option<Expression> {
 
 fn parse_bin_op(
  bin_op: &serde_json::Map<String, Value>,
- binary_operators: HashMap<&str, Box<dyn Fn(Box<Expression>, Box<Expression>) -> Expression>>,
+ binary_operators: HashMap<&str, BinOp>,
 ) -> Option<Expression> {
  // we know there is a single key value pair in this object
  // extract the value, ignore the key