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

Magicloud Magiclouds magicloud.magiclouds at gmail.com
Fri Feb 3 07:29:17 CET 2012


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....

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



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