`vector-fold``kons``knil``vec_1``vec_2``···`procedureThe fundamental vector iterator.

`Kons`is iterated over each index in all of the vectors, stopping at the end of the shortest;`kons`is applied as`(kons i state (vector-ref vec_1 i) (vector-ref vec_2 i) ···)`where`state`is the current state value — the current state value begins with`knil`, and becomes whatever`kons`returned at the respective iteration —, and`i`is the current index.The iteration is strictly left-to-right.

Examples:

Find the longest string's length in

`vector-of-strings`.(vector-fold (λ (index len str) (max (string-length str) len)) 0 vector-of-strings)

Produce a list of the reversed elements of

`vec`.(vector-fold (λ (index tail elt) (cons elt tail)) '() vec)

Count the number of even numbers in

`vec`.(vector-fold (λ (index counter n) (if (even? n) (+ counter 1) counter)) 0 vec)