[Haskell-cafe] Backward compatibility

[Byron Hale]

Hello, everyone,

I was just in the process of trying to get Haskell 7.6 installed. First 
I surveyed all the current OSes that seemed to support it. FreeBSD 9.1 
seemed like a good candidate.  However, FreeBSD 9.1 has many practical 
problems of its own.  So far, I have 7.4 installed, but not 7.6.  Would 
the MAC be better at this? Anyway,  it seems that much of Hackage will 
not be usable. Perhaps I should just run it on Windows, as it seems 
likely to install there and much of Hackage already didn't work there.

I welcome any constructive suggestions.

Best Regards,

Byron Hale

On 5/1/2013 10:27 PM, Adrian May wrote:
> Hi All,
>
> Please don't interpret this as a rant: I'm just feeling a bit 
> disappointed about probably having to give up on Haskell.
>
> Let's face it: this decision to change the default syntax in GHC7 
> means that right now Haskell looks about as stable as Ruby on Rails.
>
> I just tried to use Flippi. It broke because of the syntax change so I 
> tried WASH. I couldn't even install it because of the syntax change. I 
> persisted for a while but gave up because getPackageId doesn't exist 
> in any form at all anymore. This was only the install script: what 
> would WASH itself have in store for me to get my brain around?
>
> What are my choices here:
>
> 1) Revert to GHC6 or put pragmas and compiler switches everywhere, 
> switch 2010 off globally with cabal or even make an alias of ghc: That 
> means I'll gradually clash with people who decide ...
> 2) Convert all my code and a lot of other peoples' to the new syntax, 
> thereby exacerbating the problem that ruled out 1.
>
> Either way, we're looking at a long period during which a large 
> portion of the libraries will be incompatible with the other portion, 
> and nobody will know which style to write. I don't know if or when 
> WASH or any other library will convert, or even if I'd prefer that to 
> happen sooner or later, because that would depend on when other 
> libraries do and how I'd worked around it in the meantime. Altogether 
> that means I can't sensibly decide to rely on any library, so I can't 
> use Haskell. I'll just have to go back to fumbling around in XSL, PHP 
> and the like. Is Haskell 2010 really so much better that it justifies 
> this?
>
> I just saw that movie "The Words": the moral of the story is that you 
> shouldn't try to change your mistakes.
>
> ...
>
> Apparently it's not only 2010. I now find that buildng the Haskell 
> Platform wants GHC 7.4.2, not 7.4.1 because of the line "import 
> Prelude" (if I remember rightly,) and even when I follow the rules 
> precisely I still get several different deprecation warnings. The 
> prelude is not exactly obscure. If you deprecate that you've broken 
> everything. Is it really impossible to keep such a basic mantra 
> meaningful from one minor version to the next? Java was fond of 
> deprecating things in the early days, but when they said "deprecated" 
> they didn't mean "switched off", let alone that it would lead to a 
> syntax error. They just meant "not trendy anymore."
>
> It's a very common illusion to believe that the central thing in your 
> life is also the central thing in everybody else's. That's why things 
> like Norton take over your whole machine: those guys believe that the 
> only reason you bought the computer was to fight viruses, because 
> that's what most of the machines in their office were bought for.
>
> There seems to be something similar going on in the way Haskellers are 
> expected to update all their code whenever GHC decide to issue an 
> update. But in reality we have jobs of our own. I'd like to choose 
> Haskell over XSL because I think it'll enable me to write web sites 
> more efficiently, not because I want to forget all about my job and 
> savour the brilliance of the latest Haskell version. But in reality 
> I'm just sitting here waiting for the Platform to compile just in case 
> it's the Ubuntu package's fault, but I know it won't help. I'll just 
> get other problems instead. Reality is that the whole ecosytem is in 
> disarray because of this lack of respect for backward compatibility. 
> At least Rails can plead that it's relatively new, but Haskell has 
> been around for over 20 years.
>
> I understand that progress has to be made, and it would be nice if 
> people did just update all their code quickly so you could switch off 
> old stuff and move on. But it's not hard to survey the code that's out 
> there and see how much stuff you'd be breaking if you did. If it's not 
> a lot, then switching it off to wake them up would be an acceptable 
> compromise. But it looks to me as if a lot of very important stuff is 
> still failing on the GHC from November 2010, so clearly things are 
> going too fast. Adding new stuff is great, and sometimes the new stuff 
> clashes with the old stuff. But how much of that deprecated stuff 
> really *needed* to be switched off, and couldn't the new stuff 
> have been designed so as not to force that?
>
> In principle this is the best language on the planet, but with all 
> these version gotchas I don't know that I can use it anymore. What a 
> tragedy. I can't even think of a suggestion as to how Haskell should 
> try to get out of this mess now.
>
> Adrian.
>
>
>
>
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