chickadee » random-access-lists » ral-add-left!

ral-add-left! ls item #!rest itemsprocedure
command ((oldcount newcount (lambda (ls item . items) (ral-count ls))))
requires (and (ral? ls) ((ral-item? ls) item)
              ((list-of? (ral-item? ls)) items))
ensures  (fx= newcount (fx+ (length (cons item items)) oldcount))