[Haskell-cafe] attoparsec and backtracking

[Niklas Hambüchen]

@Evan Thanks for that link, I posted a somewhat longer argument in 
there.

Personally, I'd love <||>.

On Sun 17 Mar 2013 02:02:44 GMT, Evan Laforge wrote:
> On Fri, Mar 15, 2013 at 8:49 PM, Niklas Hambüchen <mail at nh2.me> wrote:
>> Is it not possible to add an alternative (no pun intended) to <|> that
>> supports the semantics Evan wants?
>
> I assume it's the performance thing.  Presumably it would need to pass
> an extra flag with to the failure continuation to tell it to not
> retry, though that doesn't sound so bad.  Actually, Bryan's response
> here:
>
> https://github.com/bos/attoparsec/issues/42
>
> makes it sound like he's not opposed to <||> on performance grounds,
> just that <|> is more intuitive.  I agree in general, but not in the
> case of error msgs!  So maybe I just need to see if I can make a patch
> to add <||>, sounds like Johan at least would be into that.