Haskell-Source with Extensions (HSE, haskell-src-exts) is an extension
of the standard haskell-src package, and handles most common syntactic
extensions to Haskell, including:
* Multi-parameter type classes with functional dependencies
* Indexed type families (including associated types)
* Empty data declarations
* GADTs
* Implicit parameters
* Template Haskell
and a few more. Apart from these standard extensions, it also handles
regular patterns as per the HaRP extension as well as HSX-style embedded
XML syntax.