[xmonad] is there a way to build xmonad-contrib 0.9.2 on a system with ghc 7.4.1?

Brandon Allbery allbery.b at gmail.com
Thu Jun 28 20:30:43 CEST 2012

On Thu, Jun 28, 2012 at 2:11 PM, Lara Michaels
<laramichaels1978 at yahoo.com>wrote:

> I would like to install xmonad 0.9.2 (which worked fine for me) on my
> Ubuntu 12.04 system (GHC 7.4.1).

If you're having problems with 0.10, perhaps we should be examining the
diffs between the two to see what changed and why. (Although "why" isn't
always explained; not all programmers comment or document as well as they

> XMonad/Layout/MouseResizableTile.hs:182:17:
>     Could not deduce (Eq t) arising from the literal `0'
>     from the context (Num t)
>       bound by the type signature for
>                  replaceAtPos :: Num t => [Rational] -> t -> Rational ->
> [Rational]
>       at XMonad/Layout/MouseResizableTile.hs:(182,1)-(185,61)
>     Possible fix:
>       add (Eq t) to the context of

It's telling you exactly how to fix it.

Num used to imply Eq and Show, but no longer does; as such, those
constraints may need to be added in some places where pre-7.2 compiled
things without error.  In this case we don't need Show but do need Eq.

    cabal unpack xmonad-contrib-0.9.2
    vi -n +182 XMonad/Layout/MouseResizableTile.c
    # or use your favorite editor to change "Num t =>" to "(Num t, Eq t) =>"
    cabal install # no package name here; it will build and install the
package in the current directory

brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/xmonad/attachments/20120628/0ece8f8b/attachment.htm>

More information about the xmonad mailing list