Portability | non-portable (rank-2 types, type families, scoped type variables) |
---|---|
Stability | experimental |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Safe Haskell | Safe-Infered |
Data.Reflection
Description
Based on the Functional Pearl: Implicit Configurations paper by Oleg Kiselyov and Chung-chieh Shan.
http://www.cs.rutgers.edu/~ccshan/prepose/prepose.pdf
The approach from the paper was modified to work with Data.Proxy and streamline the API by Edward Kmett and Elliott Hird.
Usage reduces to using two combinators, reify
and reflect
.
ghci> reify 6 (\p -> reflect p + reflect p) :: Int 12
The argument passed along by reify is just a data Proxy t =
Proxy
, so all of the information needed to reconstruct your value
has been moved to the type level. This enables it to be used when
constructing instances (see examples/Monoid.hs
).
Reifying any term at the type level
Instances
(B b0, B b1, B b2, B b3, B b4, B b5, B b6, B b7) => Reified (Stable b0 b1 b2 b3 b4 b5 b6 b7 a) |