• Integer literals can begin with an optional sign (+,-) and consist of a sequence of digits (0-9)

• Real literals can begin with an optional sign (+,-) followed by a sequence of digits (0-9) followed by a dot (.) followed by a sequence of digits (0-9).  Note that if there is a dot there must be one digit to the right of it.  Thus "10." is not legal syntax, whereas "10.0" is.

• Scientific literals follow the same rules as real literals with the addition of an 'e'  or 'E' followed by an optional sign followed by a sequence of (one or more) digits.