[Haskell-cafe] Re: Haddock seems to generate wrong types in newtype deriving

Brian Hulley brianh at metamilk.com
Mon Apr 24 08:36:48 EDT 2006

Simon Marlow wrote:
> Brian Hulley wrote:
>> Hi -
>> I have the following code:
>> Is this just a bug in Haddock or am I misunderstanding something
>> about Haskell?
> It's a bug / missing feature in Haddock.  Haddock is basically pretty
> dumb when it comes to understanding Haskell code; it knows about the
> syntax and the module system, and that's about all.  It makes a
> half-hearted attempt to figure out what instances you get from
> deriving clauses, but it's not complete, and you've encountered a
> case it doesn't handle.
> One day Haddock will be built on top of the GHC API, and all this will
> be fixed...

Thanks - I'm glad it's not just me!
In the meantime, I found a better workaround (since the type decl using a 
class name is not legal Haskell) is just to use -cpp to preprocess for both 
ghc and haddock so that haddock sees explicitly defined dummy instances 
instead of a newtype deriving clause, then perfect results are obtained... 

Regards, Brian. 

More information about the Haskell-Cafe mailing list