:- use_module(library(sgml)).(can be autoloaded)
INF. If a Prolog float is converted into a string it returns the XML canonical form. This form always has one digit before the decimal dot, at least one digit after it and an exponential component using the capital
E. This predicate behaves as number_string/2 for integers.
syntax_error(xsd_number) if String
is given and is not a well-formed XSD number.