RAML support for a resource PATCH (RFC 7396) - rest

Question

Problem
I'm trying to describe an API which is supposed to have resources PATCH methods work like described in RFC 7396.
Basically a POST method have a set of properties in it's body, some required some not.
PATCH (by some standards) has no fields required - requests body contains only the fields you want to update, additionally the API allows a client to "clean" a field by sending a null.
Example:
#%RAML 1.0
title: test
mediaType: [application/json]
types:
Create:
type: object
properties:
description: string
Retrieve:
type: Create
properties:
id: string
Update:
type: object
properties:
description?: nil | string
/resource:
get:
responses:
200:
body:
type: Retrieve[]
post:
body:
type: Create
/{id}:
uriParameters:
id: string
get:
responses:
200:
body:
type: Retrieve
patch:
body:
type: Update
responses:
200:
body:
type: Retrieve
in the example I have a Update type specified just for that task, because... Create has a required description, Retrieve inherits from Create as it should return all it's fields and the additional id, Update can't inherit from Create as RAML does not allow to override a required field with one that is not required.
Questions:
Is there a better way to describe that API?
If not is nil | string the proper way to go when writing that Update type "from scratch"?

Answer 1

I don't think there's a better way. Only thing is, if you have not required properties in both the create and the update, then you could create a base type.
Yes, nil | [type] is the way to go. You need to be able to "clean" the property by sending null.