These are predicate functions that test a condition of a single number
argument and returns t
if the condition tests true and returns
nil
otherwise.
zerop x | Function |
Tests for the condition that the given number x is zero.
plusp x | Function |
Tests for the condition that the given number x is non-zero and positive.
minusp x | Function |
Tests for the condition that the given number x is non-zero and negative.
oddp x | Function |
Tests for the condition that the given number x is odd.
evenp x | Function |
Tests for the condition that the given number x is even.