reduce

(reduce f initial list)

Combines the elements of list from the left with the two-argument procedure f, as SRFI-1 and MIT Scheme do: each element is the first argument and the result so far the second, (f e3 (f e2 e1)). An empty list answers initial, and a one-element list answers its element without calling f. A Structure and Interpretation of Computer Programs (SICP)/MIT name, not R7RS: no library exports it, so it is visible only to a file with no import and at the REPL.