:decimal_classification — swaps same-arity Decimal classification predicates.

The family keeps the original argument and swaps between related boolean predicates:

Decimal.positive?(num) # -> Decimal.negative?(num)
Decimal.negative?(num) # -> Decimal.positive?(num)
Decimal.nan?(num)      # -> Decimal.inf?(num)
Decimal.inf?(num)      # -> Decimal.nan?(num)

It supports qualified, aliased, imported, and piped Decimal calls.