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A bunch of lazy programmers that I know looked at some code that had a lot of:

@foo = []
@bar = []
@baz = []

Instead they wanted to do:

create_many_arrays :foo, :bar, :baz

NOTE: watching someone do "foo = bar = baz = []" is fun :)

So:

def create_many_arrays(*arraynames)
  params = arraynames.join ','
  arrays = ''
  attrs = ''

  arraynames.each do |name|

    thename = name.to_s

    arrays += "@#{thename} = []\n"

    attrs += "attr_accessor :#{name}\n"

  end

  code = <<-END_OF_CODE

    alias :__dion__initialize :initialize

    #{attrs}

    def initialize

      __dion__initialize

      #{arrays}

    end

    def initialize(*incoming)

      __dion__initialize *incoming

      #{arrays}

    end

    END_OF_CODE

    class_eval code

  end



class Foo

  create_many_arrays :foo, :bar

end

f = Foo.new

f.foo 

f.foo << 1

f.foo

class Bar

  attr_accessor :a

  def initialize(a)

    @a = a

  end

  create_many_arrays :foo, :bar

end

After a broken impl like this, you then realise that there is no real reason to want to do this, and your own code is broken if you want data structures like this.