Floating point

Floating point numbers (the Num type) are written in the standard 'e' scientific notation:

2e2      # same as 200e0, 2e2, 200.0e0  and 2.0e2
6.02e23
-2e48
1e-9
1e0

A number like 3.1416 is specifically not floating point, but rational (the Rat type), equivalent to 3927/1250. On the other hand, Num(3.1416) would be considered a floating literal though by virtue of mandatory constant folding.