[Haskell-cafe] Call for discussion: OverloadedLists extension

Chris Smith cdsmith at gmail.com
Sun Sep 23 17:51:18 CEST 2012

Michael Snoyman <michael at snoyman.com> wrote:
> That said, it would be great to come up with ways to mitigate the
> downsides of unbounded polymorphism that you bring up. One idea I've
> seen mentioned before is to modify these extension so that they target
> a specific instance of IsString/IsList, e.g.:
> "foo" ==> (fromString "foo" :: Text)

That makes sense for OverloadedStrings, but probably not for
OverloadedLists or overloaded numbers... String literals have the
benefit that there's one type that you probably always really meant.
The cases where you really wanted [Char] or ByteString are rare.  On
the other hand, there really is no sensible "I always want this"
answer for lists or numbers.  It seems like a kludge to do it
per-module if each module is going to give different answers most of
the time.


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