module Fugit

def do_parse(s, opts={})
  opts[:at] = opts[:in] if opts.has_key?(:in)
  result = nil
  errors = []
  %i[ cron duration nat at ]
    .each { |k|
      begin
        result ||= (opts[k] != false && self.send("do_parse_#{k}", s))
      rescue => err
        errors << err
      end }
  return result if result
  raise(
    errors.find { |r| r.class != ArgumentError } ||
    errors.first ||
    ArgumentError.new("found no time information in #{s.inspect}"))
end