application_controller.rb

class ApplicationController < ActionController::Base
  
  before_filter :compound_date_values
  
  protected

  def compound_date_values(h=params,prefix=[])
    to_fix = {}
    h.each do |k, v|
      if v.is_a? Hash
        compound_date_values(v,prefix+[k])
      end
      if m = k.match(/^([a-zA-Z_]+?)\(([12345])i\)$/)
        if !prefix.empty?
          params.send_chain(prefix.map{|a| [:[],a]}).delete(k)
        else
          params.delete(k)
        end
        to_fix[m[1]] = {} unless to_fix[m[1]]
        to_fix[m[1]][m[2].to_i] = v.to_i
      end
    end
    to_fix.each do |k,v|
      if v.keys.size == 3
        d = Date.new(v[1], v[2], v[3])
      elsif v.keys.size == 5
        d = DateTime.new(v[1], v[2], v[3], v[4], v[5])
      end
      if !prefix.empty?
        params.send_chain(prefix.map{|a| [:[],a]})[k] = d
      else
        params[k] = d
      end
    end
  end

end

object.rb

class Object
  def send_chain(v)
    this = self
    v.each do |k|
      return nil if this.nil?
      this = this.send(*k)
    end
    this
  end
end