Set ruby 2.0 keyword arguments with attr_accessor on initialize

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一向
一向 2021-02-13 10:44

How can I dynamically set without having to write the same code all over.

Right now the code looks like this:

def initialize(keywords: keywords, title: t         


        
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  • 2021-02-13 11:25

    Here is a working example based on Sawa's answer. Option number #1 is not working right with inheritance.

    class CsvOutline
      def initialize( headers: [],
                      body: [],
                      folder: 'tmp',
                      file_prefix: 'test',
                      filename: "#{file_prefix}_#{Time.zone.now.strftime("%Y%m%d%H%M%S")}.csv",
                      path: File.join(folder, filename))
        # Set instance variables and attribute accessors based on named parameters in initialize
        local_variables.each do |k|
          class_eval do
            attr_accessor k
          end
          v = eval(k.to_s)
          instance_variable_set("@#{k}", v) unless v.nil?
        end
      end
    end
    

    now if I was to create a child class

    class ReportCsv < CsvOutline
      def initialize
         super(folder: 'reports', file_prefix: 'Report')
      end
    end 
    

    Now the child will initialize with the proper folder and file_prefix. If I was to use the second option - they'll be initialized to nil.

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  • 2021-02-13 11:32
    def initialize(keywords: nil, title: nil, url: nil, adsetting: nil)
      local_variables.each do |k|
        v = eval(k.to_s)
        instance_variable_set("@#{k}", v) unless v.nil?
      end
    end
    

    or following John Ledbetter and Cary Swoveland's suggestion:

    def initialize(keywords: nil, title: nil, url: nil, adsetting: nil)
      method(__method__).parameters.each do |type, k|
        next unless type == :key
        v = eval(k.to_s)
        instance_variable_set("@#{k}", v) unless v.nil?
      end
    end
    
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