String functions

contains()        # font[contains(@class,"head")]
starts-with()     # font[starts-with(@class,"head")]
ends-with()       # font[ends-with(@class,"head")]

concat(x,y)
substring(str, start, len)
substring-before("01/02", "/")  #=> 01
substring-after("01/02", "/")   #=> 02
translate()
normalize-space()
string-length()