A floating point number (floating_point_literal) is a numeric literal that specifies a number as a floating point number.
<floating_point_literal> ::= <mantissa>E<exponent>
| <mantissa>e<exponent>
<mantissa> ::= <fixed_point_literal>
<exponent> ::= [<sign>][[<digit>]<digit>]<digit>
<sign> ::= + | -
<digit> ::= 0 | 1 | 2 | | 3 | 4 | 5 | 6 | 7 | 8 | 9
1e160
-765E-04