/**
* This method extracts characters from a string and returns them.
* @param str the input string to extract from
* @param start the character to start extracting from
* @param end the character to start extracting from
* @return the extracted characters
* @example
* extract("bingle", 3 ) will return "gle"
* extract("bingle", 3, 4 ) will return "gl"
*/
varargs string extract( string str, int start, int end ) {
if( end )
return str[start..end];
return str[start..];
} /* extract() */