rational,
real,
number,
t
The canonical representation of a rational is as an integer if its value is integral, and otherwise as a ratio.
The types integer and ratio
are disjoint subtypes of type rational.
Abbreviating.
(rational [lower-limit [upper-limit]])
lower-limit, upper-limit—interval designators
for type rational.
The defaults for each of lower-limit and upper-limit is the symbol *.
This denotes the rationals on the interval described by lower-limit and upper-limit.