[Haskell-beginners] confusion over yesod-forms-0.2.0

Michael Litchard michael at schmong.org
Thu Jun 23 03:52:33 CEST 2011

I installed the new yesod-forms-0.2.0
I tried out the sample program hello-forms.hs. The new changes work
just fine. No problems. I don't understand some of the notation, but
that didn't stop me from using yesod-form prior to the changes. I
copied the style of hello-form
exactly, I think. But I got a compile error. I don't think the error
indicates the actual problem, and I suspect I have left out something.
Below is a link to hello-form, the code I am trying to compile and the
error I get. I would appreciate any insight offered.




    No instance for (RenderMessage Aframe FormMessage)
      arising from a use of `selectField'
    Possible fix:
      add an instance declaration for (RenderMessage Aframe FormMessage)
    In the first argument of `areq', namely `(selectField tests)'
    In the second argument of `(<*>)', namely
      `areq (selectField tests) "Pick a test" Nothing'
    In the second argument of `($)', namely
      `pure (,)
       areq (multiSelectField servers) "Pick some servers" Nothing
     areq (selectField tests) "Pick a test" Nothing'

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