+ ,@(when (and (or prefixp per-line-prefix-p)
+ (not (and (sb!xc:constantp (or prefix per-line-prefix) env)
+ ;; KLUDGE: EVAL-IN-ENV would
+ ;; be useful here.
+ (typep (eval (or prefix per-line-prefix)) 'string))))
+ `((unless (typep ,(or prefix per-line-prefix) 'string)
+ (error 'type-error
+ :datum ,(or prefix per-line-prefix)
+ :expected-type 'string))))
+ ,@(when (and suffixp
+ (not (and (sb!xc:constantp suffix env)
+ (typep (eval suffix) 'string))))
+ `((unless (typep ,suffix 'string)
+ (error 'type-error
+ :datum ,suffix
+ :expected-type 'string))))