ghc-reflection

Reifies arbitrary terms into types that can be reflected back into terms

This package addresses the /configuration problem/ which is propagating configurations that are available at run-time, allowing multiple configurations to coexist without resorting to mutable global variables or 'System.IO.Unsafe.unsafePerformIO'. That package is an implementation of the ideas presented in the paper "Functional Pearl: Implicit Configurations" by Oleg Kiselyov and Chung-chieh Shan (<<a href="http://okmij.org/ftp/Haskell/tr-15-04.pdf">http://okmij.org/ftp/Haskell/tr-15-04.pdf</a> original paper>). However, the API has been streamlined to improve performance. Austin Seipp's tutorial <<a href="https://www.schoolofhaskell.com/user/thoughtpolice/using-reflection">https://www.schoolofhaskell.com/user/thoughtpolice/using-reflection</a> Reflecting values to types and back> provides a summary of the approach taken by this library, along with more motivating examples.