Abusing ActiveModel::Validations

MyParams.rb

class MyParameter::Base < OpenStruct
  def initialize(name:, description:, validations: proc {})
    @validator = Class.new(Struct.new(:value)) do
       include ActiveModel::Validations
       instance_eval(&validations)
       def self.model_name()
         ActiveModel::Name.new(self, nil, "temp")
       end
    end
  end
  
  def validate(value)
    v = validator.new(value)
    v.validate
    v.errors[:value].messages
  end
end

MyParameter.new(name: "example_param", description: "here's what I do",
                validations: proc { validates_inclusion_of :value, in: [1,2,3] })