Primary and secondary constructors

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In Crystal this is handled via the differentiation between def initialize and def self.new. Usually the rule of thumb is use self.new overloads to transform the arguments to fit a smaller amount of initialize methods. E.g. your example could be written as:

class Test
  def self.new(f_or_s : Float64 | String) : self
    new f_or_s.to_i
  end
 
  def initialize(@value : Int32)
    raise ArgumentError.new "parameter error" if @value > 50
  end
end

Also checkout Constructor variants and inheritance, as it has some more detailed information on how the two relate, especially when inheritance is introduced.

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