Я ☞ Operators ☞ yio

Precedence: 7

`yio` - [Y]oneda [I]dentity c[O]variant

How to read: modify the second argument covariantly, ignore the first one.

Works the same way as yo but for a 2-nd argument of a functor.

`yio` : t _ a `AR_` into (from a o) (t _ o)
 `yo` :  t a  `AR_` into (from a o)  (t o)