lispdoc - results for map-systems

(asdf:map-systems fn)
Function: Apply FN to each defined system. FN should be a function of one argument. It will be called with an object of type asdf:system.
(map-into result-sequence function &rest sequences)
(defun xform (fn seq) (map-into seq fn seq))
Mentioned in:
CLtL2 - 14.2. Concatenating, Mapping, and Reducing Sequences
HyperSpec - Function MAP-INTO
PCL - sequence mapping functions
Successful Lisp - chapter12