decimal_checked Design

State Model

DecimalChecked is an immutable product of value, IEEE context, latest flags, and accumulated flags. Construction forces DecimalContext::ieee754() so a GDA-profile context cannot leak into this package.

Transitions

Each method runs one contextual operation. The returned value becomes the next value, returned flags become raised, and combine adds them to flags. Exceptional IEEE results remain defined values. with_context explicitly reapplies the current value under a new IEEE context and records that step.

Composition Boundary

Binary methods accept plain Decimal operands. Accepting another DecimalChecked would require an arbitrary rule for merging contexts and flag histories. Operators are intentionally not implemented for the same reason. The wrapper adds constant state-copy and flag-combine work around the delegated numeric operation.