AbstractHaskell
===============

Extends abstract curry by type classes.


> import AbstractCurry
> import AbstractCurryPrinter

Types
-----

A type class consists of a class name and a number of class arguments:

> data TypeClass = TypeClass QName [CTypeExpr]


An instance declaration consists of constraints, the instanciated class and
function declarations.

> data InstanceDecl = Instance [TypeClass] TypeClass [HFuncDecl]


A haskell function declaration is an abstract curry function declaration
extended by type class constraints.

> data HFuncDecl = HFunc QName Int CVisibility [TypeClass] CTypeExpr CRules


The following Haskell programm type is an extension of `CurryProg` including
instance declarations and haskell function declarations.

> data HaskellProg = HaskellProg String          -- name
>                                String          -- header
>                                [String]        -- imports
>                                String          -- external definitions
>                                [HTypeDecl]     -- types
>                                [InstanceDecl]  -- instance declarations
>                                [HFuncDecl]     -- haskell functions
>                                [COpDecl]       -- operators


> data HTypeDecl = HTypeDecl [TypeClass] CTypeDecl [QName]