class Reline::LineEditor

def call_completion_proc_with_checking_args(pre, target, post) 

def call_completion_proc_with_checking_args(pre, target, post)
  if @completion_proc and target
    argnum = @completion_proc.parameters.inject(0) { |result, item|
      case item.first
      when :req, :opt
        result + 1
      when :rest
        break 3
      end
    }
    case argnum
    when 1
      result = @completion_proc.(target)
    when 2
      result = @completion_proc.(target, pre)
    when 3..Float::INFINITY
      result = @completion_proc.(target, pre, post)
    end
  end
  result
end