[Haskell-cafe] HList and Type signatures / synonyms

Edward Z. Yang ezyang at MIT.EDU
Sun Sep 6 20:44:52 EDT 2009

Excerpts from Günther Schmidt's message of Sun Sep 06 19:40:05 -0400 2009:
> I keep accumulating values and right now use plain tuples for that. I end  
> up with a 12 element tuple and things are a bit messy.

Hi, you may want to consider using the Writer monad. [1]

> I'd like to use extensible Records from HList instead, thing is I'd like  
> to keep putting type signatures in my code. As it turns out that seems to  
> be where it gets messy with HList.

Perhaps more precisely explaining your problem domain would be useful.


[1] http://www.haskell.org/all_about_monads/html/writermonad.html

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