class Chronic::Sign

def self.scan(tokens, options)

Returns an Array of tokens.

options - The Hash of options specified in Chronic::parse.
tokens - An Array of tokens to scan.

tags to each token.
Scan an Array of Token objects and apply any necessary Sign 
def self.scan(tokens, options)
  tokens.each do |token|
    if t = scan_for_plus(token) then token.tag(t); next end
    if t = scan_for_minus(token) then token.tag(t); next end
  end
end

def self.scan_for_minus(token)

Returns a new SignMinus object.

token - The Token object we want to scan. 
def self.scan_for_minus(token)
  scan_for token, SignMinus, { /^-$/ => :minus }
end

def self.scan_for_plus(token)

Returns a new SignPlus object.

token - The Token object we want to scan. 
def self.scan_for_plus(token)
  scan_for token, SignPlus, { /^\+$/ => :plus }
end

def to_s 

def to_s
  'sign'
end