Derive Template Haskell's Lift class for datatypes.

Version on this page:0.8.1
LTS Haskell 22.30:0.8.4@rev:2
Stackage Nightly 2024-07-22:0.8.4@rev:2
Latest on Hackage:0.8.4@rev:2

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BSD-3-Clause licensed by Ian Lynagh
Maintained by Ryan Scott
This version can be pinned in stack with:th-lift-0.8.1@sha256:51ffb3c76b2175405f643d5461a07820fade6c5ac635698a87afe3aba35ae343,2544

Module documentation for 0.8.1

Derive Template Haskell's Lift class for datatypes using TemplateHaskell. The functionality in this package has largely been subsumed by the DeriveLift language extension, which is available in GHC 8.0 and later versions. This package can still be useful as a uniform way to derive Lift instances that is backwards-compatible with older GHCs.

The following libraries are related:

  • The th-orphans package provides instances for template-haskell syntax types.

  • The th-lift-instances package provides Lift instances for types in base, text, bytestring, vector, etc. Some of these instances are only provided for old versions of their respective libraries, as the same Lift instances are also present upstream on newer versions.


Change Log

All notable changes to this project will be documented in this file.

[0.8.1] - 2019-12-06

  • Support GHC 8.10/template-haskell-2.16.
  • Derive implementations of liftTyped (in addition to lift) when using template-haskell-2.16 or later.
  • Fix a bug in which derived Lift instances for data types containing Addr# would fail to typecheck.

[] - 2019-05-09

  • Support GHC 8.8/template-haskell-2.15.

[0.8] - 2019-04-26

  • Use TemplateHaskellQuotes where available

[0.7.11] - 2018-08-27

  • Support for GHC 8.6.

[0.7.10] - 2018-02-01

  • Add support for data families

[0.7.9] - 2018-02-01

  • Lift instances for Identity and Const.

[0.7.8] - 2018-02-01

  • GHC 8.4 compatibility.

[0.7.7] - 2015-04-19

  • GHC 8.2 compatibility.

[0.7.6] - 2015-01-18

  • GHC 8.1 compatibility.

[0.7.5] - 2015-11-19

  • Added makeLift, for cases when it’s necessary to write the instance manually. (Thanks to Ryan Scott).
  • Support empty datatypes and unboxed types.

[0.7] - 2014-12-07

  • Support GHC 7.9 and hopefully 7.10, thanks to Richard Eisenberg.
  • On versions of GHC that support role inference, don’t constrain phantom type variables.
  • Get rid of some orphan instances when using GHC >= 7.9.

[0.6] - 2013-12-09

  • Support GHC 7.8, thanks to Michael Snoyberg.
  • Support existentially quantified type variables in datatype declarations.
  • Handle exotic kinds properly.

[0.5.2] - 2010-09-19

  • Support older GHCs and Cabal, thanks to Ben Millwood.

[0.5] - 2010-08-05

  • Support for contexts in datatypes, thanks to Ben Millwood.
  • deriveLiftWith becomes deriveLift' and takes an Info structure rather than a custom reification function.
  • Add deriveLiftMany to derive many Lift instances in one go.

[0.4] - 2010-08-02

  • Add support for newtypes and records syntax, thanks to a patch by Ben Millwood.
  • Add support for infix constructors.
  • deriveLift returns a list of declarations.
  • New deriveLiftWith function with custom reification, following a feature request by Jonas Duregård.

[0.3] - 2010-03-24

  • Port to Template Haskell 2.4.
  • Maintainer is now Mathieu Boespflug.

[0.2] - 2006-09-06

Initial release by Ian Lynagh.