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return expr
The ‘return’ construct terminates a loop and returns the value of the specified
expression as the value of the loop. This construct is similar to the Common
Lisp special form return-from and the Common Lisp macro return.
The Loop Facility supports the ‘return’ construct for backward compatibility with older loop implementations. The ‘return’ construct returns immediately and does not execute any ‘finally’ clause that is given.
;;; Signal an exceptional condition.
(loop for item in '(1 2 3 a 4 5)
when (not (numberp item))
return (cerror "enter new value"
"non-numeric value: ~s"
item)) ;Signals an error
;;; >>Error: non-numeric value: A
;;; The previous example is equivalent to the following one.
(loop for item in '(1 2 3 a 4 5)
when (not (numberp item))
do (return
(cerror "enter new value"
"non-numeric value: ~s"
item))) ;Signals an error
;;; >>Error: non-numeric value: A