Reading floats
When the reader sees a number like “3.0” with no exponent marker, the reader will convert it into a single-float by default. You can change what float type is used for conversion by changing *read-default-float-format* to another float type.
For example:
* (/ 22.0 7.0) 3.142857 * (setf *read-default-float-format* 'double-float) DOUBLE-FLOAT * (/ 22.0 7.0) 3.142857142857143
The printer will also omit exponent markers if the float type of the number being printed matches *read-default-float-format*.
