8.1 Predicates on Numbers

These functions return t if the specified condition is true of the numerical argument, or nil otherwise.

Function: plusp number

This predicate tests whether number is positive. It is an error if the argument is not a number.

Function: minusp number

This predicate tests whether number is negative. It is an error if the argument is not a number.

Function: oddp integer

This predicate tests whether integer is odd. It is an error if the argument is not an integer.

Function: evenp integer

This predicate tests whether integer is even. It is an error if the argument is not an integer.

Function: floatp-safe object

This predicate tests whether object is a floating-point number. On systems that support floating-point, this is equivalent to floatp. On other systems, this always returns nil.