The Haskell 98 Report: Declarations

The declarations in the syntactic category topdecls are only allowed at the top level of a Haskell module (see Chapter 5), whereas decls may be used either at the top level or in nested scopes (i.e. those within a let or where construct). For exposition, we divide the declarations into three groups: user-defined datatypes, consisting of type, newtype, and data declarations (Section 4.2); type clas