zerop

Type:	-	predicate function (subr)
Source:	-	xlmath.c

Syntax

(zerop expr)

expr - the numeric expression to check
returns -  T  if the number is zero, NIL otherwise

Description

The 'zerop' predicate function checks to see if the number 'expr' is zero.  T  is returned if the number is zero, NIL is returned otherwise. An error is generated if the 'expr' is not a numeric expression:

error: bad argument type

Examples

(zerop 0)                ; returns T
(zerop 0.0)              ; returns T
(zerop 99999.9)          ; returns NIL
(zerop -0.000000000002)  ; returns NIL

(zerop 'a)               ; error: bad argument type
(setq a 0)               ; set value of A to 0
(zerop a)                ; returns T

See the zerop predicate function in the XLISP 2.0 manual.

  Back to Top