zero?(3scm) Scheme Programmer's Manual zero?(3scm)

zero?, flzero?, fxzero? - test if a number is zero 

(import (rnrs))                     ;R6RS
(import (rnrs base))                ;R6RS
(import (scheme r5rs))              ;R7RS
(import (scheme base))              ;R7RS
(import (rnrs arithmetic flonums))  ;R6RS
(import (rnrs arithmetic fixnums))  ;R6RS


(zero? z)
(flzero? fl)
(fxzero? fx)

Test whether the number object z is zero. This procedure works on all number objects, up to and including complex numbers.

The flzero? variant is restricted to flonums and the fxzero? variant is restricted to fixnums.

Returns #t if the number is zero, otherwise #f. 

(zero? 0)         => #t
(zero? 0.0)       => #t
(zero? 0.0+0.0i)  => #t
(zero? -1)        => #f
(zero? 1/2)       => #f
(fxzero? 0)       => #t
(flzero? 0.0)     => #t
(fxzero? 1/2)     => &assertion
(flzero? 1/2)     => &assertion

Used as a shorthand for (= x 0). Use with higher-order functions is rare.

The description is the same in all Scheme reports. Compatibility will depend on general factors that affect the number system, such as implementation support for complex numbers and IEEE 754 floating point.

The restricted procedures are only specified in R6RS.

This procedure can raise exceptions with the following condition types:
&assertion (R6RS)
The wrong number of arguments was passed or an argument was outside its domain.
R7RS
The assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically.

=(3scm), >(3scm).

R4RS, IEEE Scheme, R5RS, R6RS, R7RS

This page is part of the scheme-manpages project. It includes materials from the RnRS documents. More information can be found at https://weinholt.se/scheme/manpages/.

This procedure should normally not be used on inexact numbers since inaccuracies in computations makes its use unreliable.
2021-01-06