Figure 2 identifies the precedence groups for the
binary operators defined in the standard library and indicates which
precedence groups take precedence over lower precedence groups (groups
higher up have higher precedence than groups lower down, which they point
to). All precedence groups have left associativity except for the central
group of comparison operators which are non-associative and the `**`
exponentiation operator which is right-associative.

The `+_ov`

et al. operators have the same precedence as the corresponding
non-`_ov`

operators.

Explicit parenthesization is required in expressions which mix operators that are either non-associative or unordered by the precedence partial order.