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Today's Topics:
1. Re: HTTP Download -> Save File - non-strict (Erik de Castro Lopo)
2. cabal logs (vold)
3. Re: How Haskell Fits Into an Operating System / API
Environment (Heinrich Apfelmus)
----------------------------------------------------------------------
Message: 1
Date: Mon, 12 Aug 2013 06:47:13 +1000
From: Erik de Castro Lopo <[email protected]>
To: [email protected]
Subject: Re: [Haskell-beginners] HTTP Download -> Save File -
non-strict
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII
Dan Krol wrote:
> Ah yes, the actual docs. Somehow didn't think to check that, sorry.
>
> Alright, I'll try to figure that one out, thanks. Any particular reason
> nobody just offers http over lazy I/O? Is it just because lazy I/O is
> generally discouraged? Or just particularly bad over a network?
Lazy I/O is particularly problematic when implmenting network servers
and generally discouraged for networking code.
> And is this an area where Conduit is better than Pipes?
Conduit has been around longer and is thus more mature and complete.
> There doesn't seem to be a similar http for Pipes.
I believe Andrew Cowie, author of http-streams (on top of io-streams) is
working on a Pipes version.
HTH,
Erik
--
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/
------------------------------
Message: 2
Date: Mon, 12 Aug 2013 07:35:10 +0000 (UTC)
From: vold <[email protected]>
To: [email protected]
Subject: [Haskell-beginners] cabal logs
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
If I set build-summary in cabal's config file, cabal will create duplicate
logs - the one specified in build-summary and the default build-reports.log
in the packages directory. There's also a log-dir option in the config file
which doesn't seem to do anything.
Are these bugs, or intended behaviour?
------------------------------
Message: 3
Date: Mon, 12 Aug 2013 11:23:14 +0200
From: Heinrich Apfelmus <[email protected]>
To: [email protected]
Subject: Re: [Haskell-beginners] How Haskell Fits Into an Operating
System / API Environment
Message-ID: <[email protected]>
Content-Type: text/plain; charset=UTF-8; format=flowed
Philippe Sismondi wrote:
>
> Upon reflection, probably my real concern is not about mixing
> dissimilar programming languages, but about the frequently discussed
> issue of finding production-quality libraries for a language. [..]
>
> For most of the software that I am interested in working on, there is
> a vast collection of "native" stuff available in both OS X and
> Windows. This includes, just as an example, Core Audio in OS X. [..]
>
> Moreover, I am dissatisfied with the quality of Haskell libraries
> even for those things that are not already supplied by OS vendors. In
> my opinion (and I may be wrong), hackage is littered with half-baked
> stuff, poorly documented projects started by extremely bright grad
> students and then abandoned after a year or two. (Of course, there is
> some great stuff on there too.)
Well, there are a lot of magazines at the news kiosk, too, while only a
few are of outstanding quality. That is just how a news kiosk works.
Speaking of quality, what I like most about Haskell libraries, even the
half-baked ones, is that they have very few bugs. I've been programming
functionally for a decade now, and whenever I venture into the world of
imperative languages, I always trip up bugs that just shouldn't be
there. Here two recent examples:
* HTML 5 drag and drop. Apart from the fact that the specification is
overcomplicated, Chrome doesn't even implement the spec correctly. When
the mouse enters a child element of a "dropzone'd" element, the latter
receives a "dragleave" event, but will not receive a "dragenter" event
again when the mouse moves away from the child element. Argh!
* HTML 5 WebSockets. Chrome or Safari. After a certain amount of
inactivity on the server side, the browser will close the WebSocket.
However, it will only close the client side, so the client cannot send
messages anymore. The connection to the server is still *open*, though,
and the server can happily send data. What? Also, if you connect with a
WebSocket and then reload the page and connect again, the old connection
will be reused. WTF?
These are just examples, this happens to me all the time. Curiously,
whenever I use state, my programs start to become similarly brittle.
There is no reason why state should be a fundamental element of a
programming language, and as a design pattern, state is best avoided at
all cost.
> As a result of this little thread I have come to another conclusion,
> and this is just my subjective view. Most of the software that I am
> interested in seems to live most comfortably with a stateful
> conception of the world. (The native libraries I find most useful
> certainly are stateful.) I am reasonably competent with monads and
> monad transformers in Haskell. But, to be honest, after three years
> of pluggin away at Haskell, I am not the least convinced that the
> problem of handling a changing external world in a pure functional
> language has been successfully solved by those techniques. I always
> feel as though I am using the robot arm on a space shuttle when a
> screwdriver would do. (Again, no need to rebut this - I may be wrong
> or just to stupid to use Haskell effectively - so be it.)
>
> Perhaps in the end I do not really believe that functional
> programming is the panacea that its devotees claim it to be.
>
> I think this post may mark the beginning of my abandonment of Haskell
> for many purposes.
Haskell may not be easy to learn, but it's definitely worth the effort.
Best regards,
Heinrich Apfelmus
--
http://apfelmus.nfshost.com
------------------------------
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