Either instance for IsForeign #32
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| instance eitherIsForeign :: (IsForeign l, IsForeign r) => IsForeign (Either l r) where | ||
| read value = | ||
| case (read value) :: F r of | ||
| Right rval -> pure (Right rval) |
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So this prefers the Right parse then? I think Left would be more common (aeson etc.)
Also, you can probably shorten this using <|>.
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Yup! My thinking is: Attempt to parse the thing we actually want, and if that fails, then attempt to parse the error case. If you have Either String SomeType then String would always succeed even if SomeType could have been parsed.
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Thanks! |
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The |
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I think I would prefer to provide this as a function instead of an instance. |
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I've implemented two of the functions, one Right biased and the other Left biased, and removed the instance. |
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| main = do | ||
| print $ | ||
| readJSON """{ "x":1, "y": 2, "z": 3}""" :: F Response |
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It didn't, and neither psc-ide nor pulp -w build compile the examples directory so I forgot to change it.
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Ah ok, thought I was missing something 😄
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