module Plutarch.Docs.PAsData (fooData, fooConcrete) where 
import Plutarch.Prelude

PAsData

This is a typed way of representing BuiltinData/Data. It is highly encouraged you use PAsData to keep track of what “species” of Data value you actually have. Data can be a Constr (for sum of products - ADTs), Map (for wrapping assoc maps of Data to Data), List (for wrapping builtin lists of data), I (for wrapping builtin integers), and B (for wrapping builtin bytestrings).

Consider a function that takes in and returns a B data value - aka ByteString as a Data value. If you use the direct Plutarch synonym to Data - PData, you’d have:

fooData :: Term s (PData :--> PData)
fooData = undefined

That’s not very informative - you have no way to ensure that you’re actually working with B data values. You could use PAsData instead:

fooConcrete :: Term s (PAsData PByteString :--> PAsData PByteString)
fooConcrete = undefined

Now, you have assurance that you’re working with a Data value that actually represents a builtin bytestring!

Wrapping and unwrapping to and from PAsData terms is provided by the PIsData typeclass. Specifically, by the functions- pfromData and pdata.

Some useful instances of these functions:

pfromData :: Term s (PAsData PInteger) -> Term s PInteger

pfromData :: Term s (PAsData PByteString) -> Term s PByteString

pfromData :: Term s (PAsData (PBuiltinList (PAsData a))) -> Term s (PBuiltinList (PAsData a))

pdata :: Term s PInteger -> Term s (PAsData PInteger)

pdata :: Term s PByteString -> Term s (PAsData PByteString)

pdata :: Term s (PBuiltinList (PAsData a)) -> Term s (PAsData (PBuiltinList (PAsData a)))

Note: using pfromData and pdata on builtin primitive types (such as PByteString, PInteger, …) has an associated cost. Use them sparingly and try to use them only once if possible (i.e. if you used pfromData once, plet the result and reuse it.)