Overloaded method to return a string within a string

string substr(string str, int start, int length)

string substr(string str, int start) // reads to the end of the string for finish

Can be used in conjuction with sindex to retrieve start index.

eg.

string myString;

string otherString;

otherString = "this is a string";

myString = substr(otherString,sindex(otherString,"a"));

// myString == "a string"

myString = substr(otherString,sindex(otherString,"is",4));

// myString == "is a"