[Haskell-cafe] Backward compatibility

[Adrian May]

So WASH is ancient history. OK, lets forget it.

How about the Haskell Platform? Is that ancient history? Certainly not: it
doesn't compile on anything but the very newest GHC. Not 7.4.1 but 7.4.2.
Now that's rapid maintenance, but it's still version hell because you've
got to have that compiler installed first (even though HP is supposed to be
a way to acquire haskell) and you probably haven't. You've probably got the
one from the linux package which hasn't been maintained since, ooh, must
have been at least a week ago, so you install the new one and you've
trashed cabal. How long is that puzzle gonna take to unravel? That's how I
spent my afternoon today, instead of getting on with my job. Now you might
think I was silly not to have uninstalled the linux package first, but I
tried, and then decided against it because it thought the entire OS
depended on it and actually proposed to remove everything from clib to
googleearth as a solution. It's not Haskell's fault that linux package
management is as broken as any other for the same reasons, but in an
imperfect world, it's better not to keep moving the furniture around.

Why was I trying to build the Haskell Platform at all? Because it wasn't
obvious to me that a 7 year old library would be doomed. I find it
perfectly normal to be able to compile C code from the 1970s but still run
STL through the same compiler. That's why I blamed the system instead of
the library. And unless somebody can explain to me how I would rescue my
business now if I had opted for WASH in that long-forgotten era when Barack
Obama was barely known, a Russian spy was poisoned with Polonium and a
Sudanese man was ordered to marry a goat he was caught in an intimate
position with, then I still see it that way.

Adrian.








On 2 May 2013 19:57, Ertugrul Söylemez <es at ertes.de> wrote:

> John Lato <jwlato at gmail.com> wrote:
>
> > I don't think there's anything wrong with moving at a fast pace, nor
> > do I think backwards compatibility should be maintained in perpetuity.
>
> I think this statement pretty much covers the mindset of the Haskell
> community and also explains the higher breakage rate of Haskell packages
> when compared to other languages, in particular non-static ones:  We
> move at a very fast pace.  Innovations are made all the time.  Without
> this feature we wouldn't be where we are today.
>
> Of course Haskell, being a rigorously static and correct language and a
> community that equally rigorously insists on correctness of design
> patterns we have to live with the fact that we need to fix the breakages
> we introduce, and we do that.  This is a good thing.
>
>
> > Unfortunately this leaves a lot of scope for migrations to be handled
> > poorly, and for unintended consequences of shiny new systems.  IMHO
> > both have caused issues for Haskell developers and users in the recent
> > and more distant past.  This is an issue where I think the community
> > should continually try to improve, and if a user calls out a
> > difficulty we should at least try to learn from it and not repeat the
> > same mistake.
>
> I think we do that.  The most severe breakages are introduced by new GHC
> versions.  That's why there is the Haskell Platform.  If users decide to
> move to new versions sooner they should be prepared to handle the
> breakages.  In particular a Haskell beginner simply shouldn't use
> GHC-HEAD.  Our type system makes us aware of the breakages we introduce
> and gives us the opportunity to fix them properly before exposing them
> to the users.
>
> With this in mind I don't think there is anything to learn from this
> particular case.  You wouldn't use WASH today for the same reasons you
> wouldn't use Linux 0.x.  It's a legacy, and the ideas from it have
> inspired the more recent web frameworks, which are more convenient,
> faster, more real-world-oriented.  In fact I totally expect a new
> generation of web frameworks to pop up in the future, more categorical,
> even more convenient and less error-prone.
>
>
> Greets,
> Ertugrul
>
> --
> Key-ID: E5DD8D11 "Ertugrul Soeylemez <es at ertes.de>"
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