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
$ 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.