XLISP endp

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# endp

Type: | - | predicate function (subr)
Source: | - | xlbfun.c

## Syntax

(endp list)
  list - the list to check
  returns - T if the list is empty, NIL otherwise

## Description

The 'endp' predicate function checks to see if 'list' is an empty list. T is returned if the list is empty, NIL is returned if the list is not empty. The 'list' has to be a valid list. An error is returned if it is not a list:

    error: bad argument type

## Examples

    (endp '())       ; returns T - empty list
    (endp ())        ; returns T - still empty
    (endp '(a b c))  ; returns NIL
    (setq a NIL)     ; set up a variable
    (endp a)         ; returns T - value = empty list
    (endp "a")       ; error: bad argument type - "a"
    (endp 'a)        ; error: bad argument type - A

Note: The 'endp' predicate is different from the null and not predicates in that it requires a valid list.

See the endp predicate function in the XLISP 2.0 manual.

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Nyquist / XLISP 2.0 - Contents | Tutorials | Examples | Reference