Question

As I retrieve data from a database table an array is populated. Some of the fields are defined as decimal & money fields and within the array they are represented as BigDecimal.

I use these array values to populate a CSV file, but the problem is that all BigDecimal values are by default represented in Scientific format (which is the default behaviour of the BigDecimal to_s method). I can show the values by using to_s(‘F’), but how can I override the default?

Answer 1

This is built on @Farrel’s answer, but without polluting the method namespace with a useless old_xyz method. Also, why not use default arguments directly?

class BigDecimal
  old_to_s = instance_method :to_s

  define_method :to_s do |param='F'|
    old_to_s.bind(self).(param)
  end
end

In Ruby 1.8, this gets slightly uglier:

class BigDecimal
  old_to_s = instance_method :to_s

  define_method :to_s do |param|
    old_to_s.bind(self).call(param || 'F')
  end
end

Or, if you don’t like the warning you get with the above code:

class BigDecimal
  old_to_s = instance_method :to_s

  define_method :to_s do |*param|
    old_to_s.bind(self).call(param.first || 'F')
  end
end