6.2.2 Numerical predicates

Function: number? obj

Function: complex? obj

Function: real? obj

Function: rational? obj

Function: integer? obj

[R5RS] Returns #t if obj is a number, a complex number, a real number, a rational number or an integer, respectively. In Gauche, a set of numbers is the same as a set of complex numbers, and a set of rational numbers is the same as a set of integers.

(complex? 3+4i) => #t (complex? 3) => #t (real? 3) => #t (real? -2.5+0.0i) => #t (real? #e1e10) => #t (integer? 3+0i) => #t (integer? 3.0) => #t

Function: exact? obj

Function: inexact? obj

[R5RS] Returns #t if obj is an exact number and an inexact number, respectively.

(exact? 1) => #t (exact? 1.0) => #f (inexact? 1) => #f (inexact? 1.0) => #t (exact? (modulo 5 3)) => #t (inexact? (modulo 5 3.0)) => #f

Function: zero? z

[R5RS] Returns #t if a number z equals to zero.

(zero? 1) => #f (zero? 0) => #t (zero? 0.0) => #t (zero? 0.0+0.0i) => #t

Function: positive? x

Function: negative? x

[R5RS] Returns #t if a real number x is positive and negative, respectively. It is an error to pass a non-real number.

Function: odd? n

Function: even? n

[R5RS] Returns #t if an integer n is odd and even, respectively. It is an error to pass a non-integral number.

(odd? 3) => #t (even? 3) => #f (odd? 3.0) => #t

Function: fixnum? n

Function: bignum? n

Returns #t iff n is an exact integer whose internal representation is fixnum and bignum, respectively. Portable Scheme programs don't need to care about the internal representation of integer. These are for certain low-level routines that does particular optimization.