Crystal JSON vs YAML serialization

crystal_json_vs_yaml_serialization.cr

require "json"
require "yaml"
require "secure_random"

class SerializableKlass
  YAML.mapping({
    bool:  { type: Bool,    nilable: true},
    float: { type: Float64, nilable: true},
    int:   { type: Int32,   nilable: true},
    str:   { type: String,  nilable: true}
  })

  JSON.mapping({
    bool:  { type: Bool,    nilable: true},
    float: { type: Float64, nilable: true},
    int:   { type: Int32,   nilable: true},
    str:   { type: String,  nilable: true}
  })

  RANDOM = Random.new

  macro add_to_yml(property)
    unless {{property}}.nil?
      yaml.nl
      yaml << "{{property}}: #{@{{property}}}"
    end
  end

  def initialize(bool  : (Bool    | Nil) = [RANDOM.next_bool,  nil].sample,
                 str   : (String  | Nil) = [SecureRandom.hex,  nil].sample,
                 float : (Float64 | Nil) = [RANDOM.next_float, nil].sample,
                 int   : (Int32   | Nil) = [RANDOM.next_int,   nil].sample)
    @bool  = bool
    @str   = str
    @float = float
    @int   = int
  end

  def to_yaml(yaml : YAML::Generator)
    yaml.indented do
      add_to_yml(bool)
      add_to_yml(str)
      add_to_yml(float)
      add_to_yml(int)
    end
  end

  def ==(other)
    return false unless other.is_a?(SerializableKlass)
    other.bool  == bool  && \
    other.str   == str   && \
    other.float == float && \
    other.int   == int
  end
end

require "spec"

describe SerializableKlass do
  it "can be serialized to/from JSON" do
    42.times do
      object = SerializableKlass.new
      SerializableKlass.from_json(object.to_json).should eq(object)
    end
  end

  it "can be serialized to/from YAML" do
    42.times do
      object = SerializableKlass.new
      SerializableKlass.from_yaml(object.to_yaml).should eq(object)
    end
  end
end