Я ☞ Operators ☞ yi

Precedence: 8

`yi` - [Y]oneda [I]dentity

Looks like an empty circle. The easiest operator, it maps nothing. Useful for passing multiple arguments to a function. If you see a circle, it means that you deal with a functor. In this case it doesn’t matter if functor is either covariant or contravariant since we don’t map anything according to the law:

map identity = identity

We also can use this operator to change precedence of another operator due composition rules on first operator (according to the formula):

`yi'yo`       (8 = 10 - 2)
`yii'yo`      (7 = 10 - 3)
`yiii'yo`     (6 = 10 - 4)
`yiiii'yo`    (5 = 10 - 5)