[Haskell-cafe] Curious why "cabal upgrade parsec" not installing latest version

[Peter Schmitz]

Thomas,
Ivan,
Thanks much for the info.
-- Peter

On Wed, Sep 15, 2010 at 8:00 PM, Ivan Lazar Miljenovic
<ivan.miljenovic at gmail.com> wrote:
> On 16 September 2010 12:47, Peter Schmitz <ps.haskell at gmail.com> wrote:
>> Not that I'm having any problem with parsec 2.1.0.1, but I guess I
>> would like to install the latest (3.1.0), unless there is a reason
>> not to.
>
> Because Parsec-3 apparently still has some speed regressions compared
> to Parsec-2 (I'm not qualified to note whether its design is slow or
> if you have to use it differently to get good performance out of it),
> so many developers prefer to stick to Parsec-2 for this reason.
>
> As such, and because a lot of Cabal files just state "parsec" without
> a dependency, by default cabal-install will assume that an unversioned
> dependency (which includes installing/upgrading it via the command
> line) refers to Parsec-2 and not Parsec-3.
>
> --
> Ivan Lazar Miljenovic
> Ivan.Miljenovic at gmail.com
> IvanMiljenovic.wordpress.com
>