def Design

Responsibility

def is the shared numeric vocabulary. It reexports arithmetic context/error, rounding, classification, and BigInt types; defines Sign and PartialOrder; and provides the deliberately small open Floating trait.

Selection And Boundary

Floating contains only representation-independent observation and retuning: classify, sign, precision, with_precision, and normalized. Arithmetic, ordering, parsing, context flags, and interval relations stay in narrower capability traits or concrete packages because their laws differ by domain. The helper predicates are direct pure projections over classify; this package contains no numerical algorithm, storage, IO, or global state.

Implementing Floating does not imply a field, total order, IEEE format, exact arithmetic, or checked error behavior. Downstream generic code must request the additional capabilities it actually uses.