ScottEncodingLowering

Check if a constructor name is a Data type constructor.

Check if a SIR type is the builtin Data type.

Check if a scrutinee type is a known Data variant (I, B, List, Map, Constr).

Lower the SIR to UPLC Term

Lower a single case branch for Data pattern matching.

For chooseData, branches are thunks that reference a pre-bound scrutinee. We extract values from the scrutinee within each branch.

Lower a Data constructor expression to UPLC.

Data constructors are lowered to their corresponding builtin functions:

• Data.I(value) → iData(value)
• Data.B(value) → bData(value)
• Data.List(values) → listData(values)
• Data.Map(values) → mapData(values)
• Data.Constr(tag, args) → constrData(tag, args)

Lower a match expression on Data type.

Data has 5 constructors in a fixed order:

• 0: Constr (tag: Integer, args: List[Data])
• 1: Map (entries: List[(Data, Data)])
• 2: List (elements: List[Data])
• 3: I (value: Integer)
• 4: B (value: ByteString)

The variants are dispatched via the chooseData builtin on every protocol version. The Case instruction is no alternative: it rejects a Data scrutinee before dijkstraPV, and from dijkstraPV on it only scrutinizes Data.Constr, selecting the branch by the constructor tag.

• chooseData just selects a delayed branch, it doesn't pass arguments
• We bind the scrutinee first, then extract values within each branch

Lower a field selection on Data type.

Data field selections are lowered to their corresponding builtin unpack functions:

• Data.I.value → unIData(scrutinee)
• Data.B.value → unBData(scrutinee)
• Data.List.values → unListData(scrutinee)
• Data.Map.values → unMapData(scrutinee)
• Data.Constr.constr → fstPair(unConstrData(scrutinee))
• Data.Constr.args → sndPair(unConstrData(scrutinee))