[Template-haskell] reifyDecl and reifyType not working

[Wolfgang Jeltsch]

Am Montag, 10. September 2007 14:18 schrieb Ian Lynagh:
> On Mon, Sep 10, 2007 at 08:59:45AM +0100, Simon Peyton-Jones wrote:
> > 'reifyDecl' is not a language construct; it's a function.  You need to
> > import Language.Haskell.TH to bring it into scope.
>
> It's also just called reify these days.

This is not what the GHC User’s Guide talks about when discussing reifyDecl 
and reifyType.  In an expression reifyDecl A, A has to be a type constructor 
or a class, and in an expression reifyType a, a has to be an identifier.  So 
reifyDecl and reifyType cannot be functions but must be language constructs.  
On the other hand, reify expects a value of type Name as an argument.

The problem is that I wanted to use reifyDecl as a workaround to create values 
of type Name.  The Template Haskell library doesn’t seem to provide a way to 
create a Name value which always refers to the same entity, regardless of the 
splice where it is used.  So I wanted to use workarounds like this:

    className :: Name
    ClassD _ className _ _ _ = reifyDecl Class

Best wishes,
Wolfgang