A larger alternative to the Prelude.

Latest on Hackage:

This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow to host generated Haddocks.

BSD-3-Clause licensed by Yghor Kerscher
Maintained by


Build Status Hackage BSD3 license

The Haskell Report specifies the Prelude with a minimal amount of definitions that are always available in scope for application writers. Due to its simplicity and frugality, multiple alternatives and support libraries were devised to improve upon it, including:

preliminaries is one of such alternatives and builds upon classy-prelude-conduit, with the following functionality out-of-the-box:

  • Data manipulation and structures — i.e. microlens + mono-traversable
  • Streaming
  • Concurrency
  • Parallelism
  • Read-only, write-only and read-write environments — i.e. mtl

Contrary to most other alternatives, there is no attempt at being minimal. Nevertheless, it’s shipped with microlens instead of the full-blown lens.


To use it, put the following in your .cabal file, ignoring the “…” for omited parts:

executable your-executable
  language:           Haskell2010
  default-extensions: NoImplicitPrelude
  build-depends:      preliminaries >= 0.1.6 < 1

And on each file, add import Preliminaries.

You might also want to look at this project’s Cabal file to check on useful GHC extensions to enable alongside this change.


In case something does not build or you find other unpleasant aspects of the library, please send a pull request or contact the maintainer.

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