Re: [arch-haskell] Adding another data file for dependency "hints"

On 2011-01-02 12:18 +0100 (00:7) Rémy Oudompheng wrote:

On 2011/1/2 Peter Simons wrote:

...

Rémy Oudompheng writes:

 > https://github.com/archhaskell/cabal2arch/issues#issue/19.

the gist of this issue is that "parsec >= 3.0 || == 2.1.*" is translated to "parsec>=3.0", which is just plain wrong. Now, wouldn't it be easiest to modify cabal2arch so that it translates that specification to "parsec>=2.1"? A straight-forward algorithm to accomplish that would be to use the *lowest* version bound in these kinds of alternatives. Right now, cabal2arch appears to be using the *first* version bound, which is not exactly optimal.

Am I missing something?

Dependencies are expressed as a union of intervals : here [2.1, 2.2) union [3.0, infinity) (square brackets mean inclusive, parentheses mean exclusive bounds).

* how should multiple intervals be treated ? I currently use the last one, Peter suggests to use the first one, maybe we should use the convex hull of possible dependencies ? * when the dependency spec is reduced to a single interval [a,b] should we output >=a or <=b ? if the interval is unbounded then there is no problem.

The wording of your reply implies that you are unaware that you can specify single intervals. Perhaps that was unintentional, but in case it wasn't I give the following example: depends=('foo>=a' 'foo<=b'). You can also use ">" and "<", so a single interval, bounded or unbounded, is not a problem. For multiple versions it makes sense to use the one that is satisfiable by the current set of packages. If that doesn't work, can you give an example of when a package actually needs multiple intervals?