Module  REXML::Functions 
In: 
temp/functions.rb

If you add a method, keep in mind two things: (1) the first argument will always be a list of nodes from which to filter. In the case of context methods (such as position), the function should return an array with a value for each child in the array. (2) all method calls from XML will have "" replaced with "_". Therefore, in XML, "localname()" is identical (and actually becomes) "local_name()"
a string that consists of optional whitespace followed by an optional minus sign followed by a Number followed by whitespace is converted to the IEEE 754 number that is nearest (according to the IEEE 754 roundtonearest rule) to the mathematical value represented by the string; any other string is converted to NaN
boolean true is converted to 1; boolean false is converted to 0
a nodeset is first converted to a string as if by a call to the string function and then converted in the same way as a string argument
an object of a type other than the four basic types is converted to a number in a way that is dependent on that type
A nodeset is converted to a string by returning the stringvalue of the node in the nodeset that is first in document order. If the nodeset is empty, an empty string is returned.
A number is converted to a string as follows
NaN is converted to the string NaN
positive zero is converted to the string 0
negative zero is converted to the string 0
positive infinity is converted to the string Infinity
negative infinity is converted to the string Infinity
if the number is an integer, the number is represented in decimal form as a Number with no decimal point and no leading zeros, preceded by a minus sign () if the number is negative
otherwise, the number is represented in decimal form as a Number including a decimal point with at least one digit before the decimal point and at least one digit after the decimal point, preceded by a minus sign () if the number is negative; there must be no leading zeros before the decimal point apart possibly from the one required digit immediately before the decimal point; beyond the one required digit after the decimal point there must be as many, but only as many, more digits as are needed to uniquely distinguish the number from all other IEEE 754 numeric values.
The boolean false value is converted to the string false. The boolean true value is converted to the string true.
An object of a type other than the four basic types is converted to a string in a way that is dependent on that type.