Refine the statement

velox/docs/develop/scalar-functions.rst

@@ -582,9 +582,14 @@ is assumed to have the default null behavior, e.g. null in any input produces
 a null result. In this case, the expression evaluation engine will exclude
 rows with nulls from the “rows” specified in the call to “apply”. If a
 function has a different behavior for null inputs, VectorFunctionMetadata's
-defaultNullBehavior must be set to false when it is registered. See the below
+defaultNullBehavior must be set to false during registration. See the below
 "Registration" section.
 
+.. code-block:: c++
+
+    auto metadata =
+      exec::VectorFunctionMetadataBuilder().defaultNullBehavior(false).build();
+
 In this case, the “rows” parameter will include rows with null inputs and the
 function will need to handle these. By default, the function can assume that
 all inputs are not null for all “rows".
@@ -637,8 +642,12 @@ dictionary or constant encoded. However, a deterministic function that takes
 a single argument and has default null behavior is guaranteed to receive its
 only input as a flat or constant vector. By default, a function is assumed to
 be deterministic. If that’s not the case, VectorFunctionMetadata's deterministic
-must be set to false when such function is registered. See the below "Registration"
-section.
+must be set to false during registration. See the below "Registration" section.
+
+.. code-block:: c++
+
+    auto metadata =
+      exec::VectorFunctionMetadataBuilder().deterministic(false).build();
 
 Note that :ref:`decoded-vector` can be used to get a flat vector-like interface to any
 vector. A helper class exec::DecodedArgs can be used to decode multiple arguments.
@@ -865,17 +874,9 @@ Use exec::registerVectorFunction to register a stateless vector function.
 
 exec::registerVectorFunction takes a name, a list of supported signatures
 and unique_ptr to an instance of the function. It is optional to provide
-metadata flag to set deterministic or defaultNullBehavior.
-
-.. code-block:: c++
-
-    auto metadata = exec::VectorFunctionMetadataBuilder()
-                      .deterministic(false)
-                      .defaultNullBehavior(false)
-                      .build();
-
-An optional “overwrite” flag specifies whether to overwrite a function if a
-function with the specified name already exists.
+metadata flag to set deterministic or defaultNullBehavior. An optional
+“overwrite” flag specifies whether to overwrite a function if a function
+with the specified name already exists.
 
 Use exec::registerStatefulVectorFunction to register a stateful vector
 function.