Idea for refactor of json properties

[beta-ziliani]

I found several JSON fields that are present with different formats. This is handle by a union of two properties:

    @[JSON::Field(key: "final_evaluation")]
    property final_evaluation_1 : String?
    @[JSON::Field(key: "finalEvaluation")]
    property final_evaluation_2 : String?

    def final_evaluation : String
      unless result = final_evaluation_1 || final_evaluation_2
        raise "Invalid final_evaluation"
      end
      result
    end

A potential refactor could be a macro:

require "json"

struct IpaProof
  include JSON::Serializable
  
  macro two_names_json_prop(name1, name2, ty)
    @[JSON::Field(key: {{name1}})]
    property {{name1}}_1 : {{ty}}?
    
    @[JSON::Field(key: {{name2}})]
    property {{name1}}_2 : {{ty}}?
    
      def {{name1}} : {{ty}}
        {{name1}}_1 || {{name1}}_2 || raise "Invalid or missing key {{name1}}"
      end
  end

  two_names_json_prop final_evaluation, finalEvaluation, String?
end

a = IpaProof.from_json %({"finalEvaluation": "hi"})
puts a.final_evaluation