cl-shiftf
cl-shiftf is an autoloaded Lisp macro in `cl-macs.el
'.
(cl-shiftf PLACE... VAL)
Shift left among PLACEs.
Example: (cl-shiftf A B C) sets A to B, B to C, and returns the old A.
Each PLACE may be a symbol, or any generalized variable allowed by `setf'.