+;;; FIXME: this would be a valid transform for certain excluded cases:
+;;; * :TEST 'CHAR= or :TEST #'CHAR=
+;;; * :TEST 'EQL or :TEST #'EQL
+;;; * :FROM-END NIL (or :FROM-END non-NIL, with a little ingenuity)
+;;;
+;;; also, it should be noted that there's nothing much in this
+;;; transform (as opposed to the ones for REPLACE and CONCATENATE)
+;;; that particularly limits it to SIMPLE-BASE-STRINGs.
+(deftransform search ((pattern text &key (start1 0) (start2 0) end1 end2)
+ (simple-base-string simple-base-string &rest t)
+ *
+ :policy (> speed (max space safety)))
+ `(block search
+ (let ((end1 (or end1 (length pattern)))
+ (end2 (or end2 (length text))))
+ (do ((index2 start2 (1+ index2)))
+ ((>= index2 end2) nil)
+ (when (do ((index1 start1 (1+ index1))
+ (index2 index2 (1+ index2)))
+ ((>= index1 end1) t)
+ (when (= index2 end2)
+ (return-from search nil))
+ (when (char/= (char pattern index1) (char text index2))
+ (return nil)))
+ (return index2))))))
+