Re: Correct parsers for bounded integral values

Jeff Clites via Haskell-Cafe <[email protected]> Mon, 21 Jul 2025 10:42:09 -0700
Newsgroups gmane.comp.lang.haskell.cafe
Message-ID <[email protected]>

> On Jul 21, 2025, at 8:43 AM, Stefan Klinger <[email protected]> wrote:
> 
> Hallo, and thanks for the discussion!

You are welcome!

> But there is a *different* read function
> 
>    read :: String -> Word8
> 
> which is not used in the scenario above, and this is the buggy one
> (and all its bounded cousins).

I think you will find, though, that `read @Word8` is intended to match the behavior of `(fromInteger @Word8) . (read @Integer)`. At least, the `Int` case is specified in the Haskell Report (in the Prelude implementation).

But I could be wrong about the intention in the other cases, you can always ask the relevant committee.

(BTW the `read` functions have other quirks, like allowing leading whitespace.)

Jeff Clites
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