Principled, portable & extensible hashing of data and types, including an implementation of the FNV-1a and SipHash algorithms. https://github.com/jberryman/hashabler

Latest on Hackage:2.0.0

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BSD-3-Clause licensed by Brandon Simmons

This package is a rewrite of the hashable library by Milan Straka and Johan Tibell, having the following goals:

  • Extensibility; it should be easy to implement a new hashing algorithm on any Hashable type; in this package we provide SipHash and FNV-1a.

  • Honest hashing of values, and principled hashing of algebraic data types (see e.g. hashable issues


  • Cross-platform consistent hash values, with a versioning guarantee. Where possible we ensure morally identical data hashes to indentical values regardless of processor word size and endianness.

  • Make implementing identical hash routines in other languages as painless as possible. In addition to SipHash, we provide an implementation of a simple hashing algorithm (FNV-1a) and make an effort to define Hashable instances in a way that is well-documented and sensible, so that e.g. one can easily implement a string hashing routine in JavaScript that will match the way we hash strings here.

Versioning: Except for instances where we specifically note that we make no promise of consistency, changes to hash values (and consequently changes to StableHashable values, where applicable) entail a major version number bump.



  • Use decodeFloat for Float and Double, for sanity and consistency with ghcjs. Hash values for these typed have changed.
  • Fix integer-gmp flag and support ghcjs (thanks to roelvandijk!)


  • Performance improvements
  • Implement a faster siphash-1-3


  • Eq, Read, Show for SipKey


  • SipKey is now a new data type with unboxed fields, instead of tuple
  • export a new mixType helper for defining StableHashable instances


  • Parameterize Hash32/64/128 types by the type of their hashed source data, to enforce legitimate equality comparisons of hashes.
  • Add StableHashable for distinguishing types with respect to their hashes across platforms and programs.


  • Added a mix64 method, in use in, Word/Int64 ByteString types and P.ByteArray
  • Hash renamed HashState and roll clarified in docs
  • instance Hashable of Float and Double now use mix32 and mix64 respectively.
  • Implemented 64-bit and 128-bit siphash
  • Instances up to 15-tuples. Now web scale!

  • (initial release)
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