If CharList is parsed, it is parsed using the Prolog syntax for numbers. Following the ISO standard, it allows for leading white space (including newlines) and does not allow for trailing white space.^{101ISO also allows for Prolog comments in leading white space. We--and most other implementations--believe this is incorrect. We also beleive it would have been better not to allow for white space, or to allow for both leading and trailing white space. Prolog syntax-based conversion can also be achieved using format/3 and read_from_chars/2.} A syntax_error exception is raised if CharList does not represent a valid Prolog number.