[Haskell-cafe] ANNOUNCE: AbortT-transformers version 1.0

Brandon S Allbery KF8NH allbery at ece.cmu.edu
Thu Sep 9 15:22:41 EDT 2010

Hash: SHA1

On 9/9/10 12:16 , Henning Thielemann wrote:
> Colin Paul Adams schrieb:
>>>>>>> "Henning" == Henning Thielemann <lemming at henning-thielemann.de> writes:
>>     Henning> On Wed, 8 Sep 2010, Gregory Crosswhite wrote:
>>> ExceptionT is a different matter because it handles "fail" as an
>>     >> uncaught error and places no restrictions on the error type, so
>>     >> one could implement the same functionality as AbortT by using
>>     >> ExceptionalT and requiring the end result be a monadic value of
>>     >> type "ExceptionalT e m e", where the exception and result types
>>     >> are the same.  However, I believe that it is better to have the
>>     >> AbortT functionality available as a separate simple library
>>     >> specialized for this purpose than to have its functionality
>>     >> buried inside a more general library that is really intended to
>>     >> be used for a different purpose.
>>     Henning> If we get rid of the notion of an exception as being
>>     Henning> something bad, and instead consider an exception as being
>>     Henning> early exit for whatever reason, I see no problem. E.g. you
>>     Henning> may well use an exception to terminate a successful search,
>>     Henning> returning the search result as exception value.
>> So where is the exceptional nature? Is a successful conclusion to a
>> search so exceptional?
> You search as long as you don't find what you are looking for. So not
> finding what you search seems to be the rule and finding it seems to be
> the exception. :-)
>> It seems to me that you want to get rid of the notion of an exception as
>> something exceptional, in which case it would be better to give it a
>> different name.
> English is not my native tongue. If 'abort' is more appropriate than
> 'exception' we may rename modules from Exception to Abort.

"Abort" is even worse, as it implies *ab*normal termination (to my mind, at
least, this suggests something closer to "error" than "exception").  In some
sense this seems closer to Prolog's cut than any kind of exception.

- -- 
brandon s. allbery     [linux,solaris,freebsd,perl]      allbery at kf8nh.com
system administrator  [openafs,heimdal,too many hats]  allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university      KF8NH
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