> let left_head = \xs. (xs f I) I err in
> ...
- > Here's another, more straightforward answer. We [[observed before|where?]] that left-folding the `cons` function over a list reverses it. Hence, it is easy to reverse a list defined in terms of its left-fold:
+ > Here's another, more straightforward answer. We [[observed before|/topics/week2_encodings#flipped-cons]] that left-folding the `cons` function over a list reverses it. Hence, it is easy to reverse a list defined in terms of its left-fold:
> let left_empty = \f z. z in ; this the same as for the right-fold encoding of lists
> let flipped_left_cons = \xs x. \f z. xs f (f z x) in ; left-folding supplies arguments in a different order than cons expects