class Chronic::Ordinal

def self.scan(tokens)
  # for each token
  tokens.each_index do |i|
    if t = self.scan_for_ordinals(tokens[i]) then tokens[i].tag(t) end
    if t = self.scan_for_days(tokens[i]) then tokens[i].tag(t) end
  end
  tokens
end

def self.scan_for_days(token)
  if token.word =~ /^(\d*)(st|nd|rd|th)$/
    unless $1.to_i > 31 || $1.to_i < 1
      return OrdinalDay.new(token.word.to_i)
    end
  end
  return nil
end

def self.scan_for_ordinals(token)
  if token.word =~ /^(\d*)(st|nd|rd|th)$/
    return Ordinal.new($1.to_i)
  end
  return nil
end

def to_s
  'ordinal'
end