- (if alphanumericp
- (loop
- for count upfrom 0
- for char = (code-char (funcall code))
- until (alphanumericp char)
- when (= 1000 count)
- do (error "After 1000 iterations ~S has still not generated an alphanumeric character :(."
- code)
- finally (return char))
- (code-char (funcall code)))))
+ (loop
+ for count upfrom 0
+ for char = (code-char (funcall code))
+ until (and char
+ (or (not alphanumericp)
+ (alphanumericp char)))
+ when (= 1000 count)
+ do (error "After 1000 iterations ~S has still not generated ~:[a valid~;an alphanumeric~] character :(."
+ code alphanumericp)
+ finally (return char))))