[Haskell-cafe] Again, version conflicting problem with cabal-install

Ivan Lazar Miljenovic ivan.miljenovic at gmail.com
Fri Feb 3 07:44:46 CET 2012


On 3 February 2012 17:29, Magicloud Magiclouds
<magicloud.magiclouds at gmail.com> wrote:
> Thank you. The document does say it more clearly than me.
> But still, currently, ghc only gives me one option: cannot be built.
> How about giving me another one: throw away the version information of
> D when building A. So when A uses types in D with B and C, it might
> work. Just the risk is on me now.
> It is not perfect, but would work sometimes....

But not always.  We'd then have other errors: "why isn't this build working?"

Types can be re-exported, class instances are implicitly imported/exported, etc.

>
> On Fri, Feb 3, 2012 at 2:04 PM, Ivan Lazar Miljenovic
> <ivan.miljenovic at gmail.com> wrote:
>> On 3 February 2012 16:54, Magicloud Magiclouds
>> <magicloud.magiclouds at gmail.com> wrote:
>>> Hello,
>>>  As I recalled, ghc works in staticly link mode. So after one library
>>> is compiled, all its build dependencies are useless. Lost, changed,
>>> wheresoever, it does not matter.
>>>  Then why the problem of version conflicting exists?
>>>  By version conflicting I mean like following. This way, A is not
>>> installable by cabal.
>>> A needs B 0.1
>>> A needs C 0.1
>>> B needs C0.2
>>
>> See the Dreaded Diamond Dependency Problem: http://www.well-typed.com/blog/9
>>
>> --
>> Ivan Lazar Miljenovic
>> Ivan.Miljenovic at gmail.com
>> IvanMiljenovic.wordpress.com
>
>
>
> --
> 竹密岂妨流水过
> 山高哪阻野云飞
>
> And for G+, please use magiclouds#gmail.com.



-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com



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