{ cabal, mtl, perl }:

cabal.mkDerivation (self: {
  pname = "happy";
  version = "1.18.4";
  sha256 = "909bec4541a92d3765e74756f752514d2d03ec7a5d3e74c18268a57fe7ffa832";
  isLibrary = false;
  isExecutable = true;
  buildDepends = [ mtl ];
  buildTools = [ perl ];
  patches = [ ./adapt-crazy-perl-regex-for-cpp-4.8.0.patch ];
  meta = {
    homepage = "http://www.haskell.org/happy/";
    description = "Happy is a parser generator for Haskell";
    license = self.stdenv.lib.licenses.bsd3;
    platforms = self.ghc.meta.platforms;
    maintainers = [ self.stdenv.lib.maintainers.andres ];
  };
})