Recursively implementing map, apply & filter in Scheme

For each of the functions map, apply, & filter, we see how built-in versions work, then we implement them recursively. I strongly suggest you try implementing them on your own before watching this video. 0:35 - Initial definitions of functions & lists used later 0:58 - Implementing "map" 2:14 - Implementing "apply" 5:21 - Implementing "filter"