This version implements the scientific mode and have revamped the float displaying system.

It adds the toggle_float <normal|science|exact> REPL command which changes the float display.

In normal mode the float is displayed with 10 decimal digits. Even when a rational solution is available. For example if you input

> 1/3 

It displays

val: float = 0.3333333333

In exact mode it displays

val: rational = 1/3 

And in science mode it displays

val: float = 3.333333333333*10⁻¹

Science mode prints with this pattern:

[0-9].[0-9]{10}\*10^(([0-9]*)|(-[0-9]*))