Re: Libraries Digest, Vol 87, Issue 16

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On 8 November 2010 08:35, Bryan O'Sullivan wrote:

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Hlint isn't a library, right? And as an application, it presumably doesn't for any practical reason need its dependencies in the platform in order to itself be included?

As I stated earlier, the policy seems to state that they do need to be there (to be able to build the platform if nothing else):

http://trac.haskell.org/haskell-platform/wiki/AddingPackages#PackageRequirem...

Well, the policy can be changed if necessary (not that I'm proposing that here). While packages may need to be present to build an application in the platform, they don't necessarily need to be exposed as part of the platform.

That's true for binary packaging systems. It would not be true for source based ones e.g. gentoo, freebsd ports, macports or indeed someone starting with just ghc and using cabal to install the platform meta-package.

 Rationale-8.5 seems to be targeted at libraries specifically.  That is, it claims there's no technical means to differentiate between blessed and non-blessed packages, which is why non-blessed packages can't be included.  But since an application doesn't expose libraries, there is a simple means to make this distinction.

My opinion is that we should keep the source based distribution mechanisms in mind, in which case the rationale applies for programs as well as libraries. If we all think it's a major problem then we could look at technical solutions, but the current model is quite nice where each cabal package is translated 1:1 into a native package. In the case of HLint specifically, I think it's quite likely that we'll get haskell-src-exts into the platform in the next round. Duncan