consp


Synopsis

(consp <expr>)

Description

Predicate if the expression is a cons cell, a not-empty list.

There are some possible definitions, all equally the same:

  (defun CONSP (lst) (not (atom lst)))
  (defun CONSP (lst) (and lst (listp lst)))
;|#+ VLISP|;
  (setq CONSP vl-consp)  ;|END #+ VLISP|;
;|#+ VILL|;
  (setq CONSP vlx-consp) ;|END #+ VILL|;

Examples

(consp nil) => nil
(consp 1) => nil
(consp '(0)) => T
(consp '(0 . 1)) => T

In Visual Lisp it is builtin as VL-CONSP, in Vital Lisp as VLX-CONSP.

Arguments

expr: any valid lisp expression

Return Value

T or nil.

Side Effects

None.

Module

(std-require 'STDINIT)

Defined in STDINIT, documented in STDLIST