[Haskell-cafe] Stacking monads
Anton van Straaten
anton at appsolutions.com
Thu Oct 2 16:32:22 EDT 2008
Andrew Coppin wrote:
> I thought ErrorT was a class name...?
No, it's the name of the error monad transformer type. "Error" is just
an ordinary monad, it's ErrorT that's the transformer. So it sounds
like the answer to your question below:
> > You could try using an exception monad transformer here
> I thought I already was?
...is no, you weren't. You need to construct your monad stack using
ErrorT, not Error.
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