Cardano.Ledger.Binary.Coders provides tools for writing EncCBOR and DecCBOR instances (see module Binary) in an intuitive way that mirrors the way one constructs values of a particular type. Advantages include:

1. Book-keeping details neccesary to write correct instances are hidden from the user.
2. Inverse EncCBOR and DecCBOR instances have visually similar definitions.
3. Advanced instances involving sparse-encoding, compact-representation, and Annotator instances are also supported.

A Guide to Visual inspection of Duality in Encode and Decode

1. (Sum c) and (SumD c) are duals
2. (Rec c) and (RecD c) are duals
3. (Keyed c) and (KeyedD c) are duals
4. (OmitC x) and (Emit x) are duals
5. (Omit p ..) and (Emit x) are duals if (p x) is True
6. (To x) and (From) are duals if (x::T) and (forall (y::T). isRight (roundTrip y))
7. (E enc x) and (D dec) are duals if (forall x . isRight (roundTrip' enc dec x))
8. (f !> x) and (g <! y) are duals if (f and g are duals) and (x and y are duals)

Duality properties of (Summands name decodeT) and (SparseKeyed name (init::T) pick required) also exist but are harder to describe succinctly.