Re: How to use Read for Data.Version

Thanks for the quick answer. Indeed, I confused Read and ReadP! --Andreas On 2021-08-14 19:06, chessai wrote:

Looking at the source code [1], Read is derived, and not using parseVersion (which has the behaviour I think you expect).

You may want to use parseVersion directly.

[1]: https://hackage.haskell.org/package/base-4.15.0.0/docs/src/Data-Version.html https://hackage.haskell.org/package/base-4.15.0.0/docs/src/Data-Version.html

On Sat, Aug 14, 2021, 11:55 Andreas Abel mailto:andreas.abel@ifi.lmu.de> wrote:

How is the parser for Data.Version supposed to work?

```haskell import Data.Version

readVersion :: String -> Version readVersion = read

main :: IO () main = print $ readVersion "8.10.5"

-- *** Exception: Prelude.read: no parse ```

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