(boundp)

(boundp item)


Determine whether an item has a value.


The boundp function determines if item has a corresponding value bound to it. If item does have a value bound to it, LISP returns T. If not, or if item is bound to nil, a nil is returned.

Examples

Code Returns
(setq x nil y 7)  
(boundp 'x) nil
(boundp 'y) T
(boundp 'z) nil

NOTE The boundp function is the opposite of the null function.

Tell me about...

(atom item)

(atoms-family format [symbol1 symbol2 ...])

(numberp item)

(setq symbol1 statement1 [symbol2 statement2] ...)

(type item)

LISP Compatibility

Programming Overview of LISP (LISt Processing) Language