Higher order versions of Prelude classes

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BSD-3-Clause licensed by Edward A. Kmett
Maintained by Edward A. Kmett

Module documentation for

Higher order versions of Prelude classes to ease programming with polymorphic recursion and reduce UndecidableInstances

See for further discussion of the approach taken here.


  • Add instances for Const
  • Add instances for tuples up to 9

  • Mark Prelude.Extras as Trustworthy

  • Added instances for the types in base where possible


  • Derived Functor, Foldable, and Traversable for Lift1 and Lift2


  • Fixed a broken #ifdef


  • Restructured so users can take advantage of default signatures
Depends on 1 package:
Used by 3 packages:
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