Obtaining Happy

If you just want to use Happy, you can build from a release. This should work the same as any other Haskell package.

Happy itself and its examples are intended to work with GHC >= 7.0.

Haskell-specific way

From Hackage via Cabal Install:

$ cabal install happy

From Stackage via Stack:

$ stack install happy

Moreover, cabal will automatically install the required version of happy based on build-tools/build-tool-depends declarations.

Operating System way

Because Happy is a dependency of GHC, it is often packaged by operating systems. Repology aggregates this info across many distros and operating systems, and Happy is actually listed twice:

The table contains links to the individual OS packages, which should provide installation instructions.