http://hackage.haskell.org/package/generics-mrsop comes with both a deep and a shallow encoding of datatypes. The paper is here: https://doi.org/10.1145/3240719.3241786 On Sat, Jan 26, 2019, 13:44 Marco Zocca

Hi all,

I'm a bit at a loss regarding this: say we have a value from a nested algebraic type (definitions at the bottom)

testT2 :: T2 testT2 = T2 B (Left 42)

a generic encoding computed with `from` only goes one level deep, leaving the sub-terms as they are :

λ> from testT2 SOP (Z (I B :* (I (Left 42) :* Nil)))

However, is it possible to recursively encode and collect all the sub-terms, until primitive types or enumerations are encountered? The encoded sub-terms from the example above are as follows:

λ> from B SOP (S (Z Nil)) λ> from (Left 32 :: Either Int Char) SOP (Z (I 32 :* Nil))

where

{-# language DeriveGeneric #-} import qualified GHC.Generics as G import Generics.SOP

data T1 = A | B | C deriving (G.Generic) instance Generic T1

data T2 = T2 { t21 :: T1 , t22 :: Either Int Char } deriving (G.Generic) instance Generic T2 _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.