[Haskell-cafe] Reply-To: Header in Mailinglists (was: About "Fun with type functions" example)

[Joachim Breitner]

Hi Bastian,

I generally observe the pattern that non-technical mailing lists tend to
set this header to help the user, while technical mailing list assume
(rightfully, IMHO) that the readers are fine without Reply-To. The
reasons against setting that I recall at the moment are:
 * Mails meant to be send privately but accidentally sent to the list
are worse than mails meant to be public but sent privately.
 * Users who send to the list with a Reply-To header set do not want
that header to be lost.
 * With some clients, the Reply-To-All feature does not always work as
expected when there is a Reply-To-Header.

Most clients have a Reply-To-List feature (Evolution on Ctrl-L) that
works fine, once you get used to it.

Greetings,
Joachim


Am Freitag, den 19.11.2010, 04:55 +0100 schrieb Bastian Erdnüß:
> Hi there,
> 
> I just put an answer two this in beginners at haskell.org.  It was not on
> purpose to move the topic.  It's just that questions I feel I can
> answer are usually beginner level questions and so I'm not often
> writing in the cafe itself.
> 
> It would make my life a little bit more easy if the mailing lists on
> haskell.org would add a Reply-To: header automatically to each message
> containing the address of the mailing list, the message was sent to.
> Usually that's the place where others would want to sent the answers
> to, I would suppose.
> 
> Is there a reason that that's not the case?  Am I missing something?
> Or am I supposed to install a more cleaver mail client which can do
> that for me?  Is there one?  Probably written in Haskell ;-)
> 
> Cheers,
> Bastian
> 
> On Nov 19, 2010, at 1:07, Daniel Peebles wrote:
> 
> > The best you can do with fromInt is something like Int -> (forall n. (Nat n)
> > => n -> r) -> r, since the type isn't known at compile time.
> > 
> > On Thu, Nov 18, 2010 at 2:52 PM, Arnaud Bailly <arnaud.oqube at gmail.com>wrote:
> > 
> >> Thanks a lot, that works perfectly fine!
> >> Did not know this one...
> >> BTW, I would be interested in the fromInt too.
> >> 
> >> Arnaud
> >> 
> >> On Thu, Nov 18, 2010 at 8:22 PM, Erik Hesselink <hesselink at gmail.com>
> >> wrote:
> >>> On Thu, Nov 18, 2010 at 20:17, Arnaud Bailly <arnaud.oqube at gmail.com>
> >> wrote:
> >>>> Hello,
> >>>> I am trying to understand and use the Nat n type defined in the
> >>>> aforementioned article. Unfortunately, the given code does not compile
> >>>> properly:
> >>> 
> >>> [snip]
> >>> 
> >>>> instance (Nat n) => Nat (Succ n) where
> >>>> toInt   _ = 1 + toInt (undefined :: n)
> >>> 
> >>> [snip]
> >>> 
> >>>> And here is the error:
> >>>> 
> >>>> Naturals.hs:16:18:
> >>>>   Ambiguous type variable `n' in the constraint:
> >>>>     `Nat n' arising from a use of `toInt' at Naturals.hs:16:18-39
> >>>>   Probable fix: add a type signature that fixes these type variable(s)
> >>> 
> >>> You need to turn on the ScopedTypeVariables extension (using {-#
> >>> LANGUAGE ScopedTypeVariables #-} at the top of your file, or
> >>> -XScopedTypeVariables at the command line). Otherwise, the 'n' in the
> >>> class declaration and in the function definition are different, and
> >>> you want them to be the same 'n'.
> >>> 
> >>> Erik
> >>> 

-- 
Joachim "nomeata" Breitner
  mail: mail at joachim-breitner.de | ICQ# 74513189 | GPG-Key: 4743206C
  JID: nomeata at joachim-breitner.de | http://www.joachim-breitner.de/
  Debian Developer: nomeata at debian.org
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part
Url : http://www.haskell.org/pipermail/haskell-cafe/attachments/20101119/2fa743a6/attachment.bin