Collection of useful functions for use with Template Haskell

Version on this page:
LTS Haskell 22.29:
Stackage Nightly 2024-07-18:
Latest on Hackage:

See all snapshots th-utilities appears in

MIT licensed
Maintained by Michael Sloan
This version can be pinned in stack with:th-utilities-,1789

Module documentation for


Build Status

The ‘th-utilities’ package provides a number of useful utilities for Template Haskell. In particular:

  • TH.Derive provides a convenient system for using TH to derive typeclass instances. It allows for open registration of TH derivers, and reuses instance syntax for invoking them.

  • TH.ReifyDataType provides utilities for reifying simplified datatype info. It omits details that you don’t usually want to handle, making it much more straightforward to generate code based on datatype structure.

  • TH.RelativePaths provides utilities for loading files based on paths relative to the cabal file. This is particularly handy for loading code into ghci even when its current dir isn’t the package dir. Ideally, this module would be used by everyone who currently uses qAddDependentFile.

  • TH.Utilities provides a miscellaneous set of utilities that are useful within this package and elsewhere.



  • Adds TH.ReifySimple, which supports reifying most of the information TH users care about.

  • Adds some utilities based on SYB, which is often useful for TH.

  • Makes relative path stuff less noisyi with GHCi.

  • First public release