First I'd like to point out the author of xmobar, Andrea Rossato, probably doesn't follow this list anymore. If you'd like to see action on these issues, you should probably forward this message to him. On Mon, Jul 14, 2008 at 10:08:45AM -0700, Fred Blasdel wrote:
I wrote a xmobar plugin to display the time as inexact text: http://www.wabdo.com/fred/FuzzyClock.hs
It uses Data.Time, not the more widespread System.Time. It's not parameter-ised because it would be a huge pain to make a xmobar plugin take a function as an argument (seems like I'd have to take it as a string and eval it), and you're going to have to modify/recompile xmobar's source to add it anyway.
I was surprised at just how un-idiomatic I found xmobar's configuration to be: * Uses format strings instead of functions * Uses property lists for the arguments to monitors instead of [(a,b)] or a data constructor
Yes, both of these are rather ugly -- it seems to have a shell script flavor to it, rather than a strongly typed combinator approach usually used in Haskell.
* Commands aren't simple functions * 'Plugins' cannot be seperated from xmobar's source (and resulting binary)
Andrea has chosen to use Read/Show serialization for xmobar rather than Haskell source ala xmonad. The things you mention are the negative aspects of this choice, but there are positive aspects -- not requiring GHC as a runtime dependency is a major one.
Currently the only way to extend xmobar's functionality without modifying/recompiling it is to use external processes. I think that having to hack/rebuild xmobar is a huge barrier to experimentation -- I could only find one other person who had published out-of-tree plugins (http://www.haskell.org/pipermail/xmonad/2008-April/005465.html).
In fact, I've written xmobar plugins but have not distributed them because there isn't really a convenient way to do it.
I think it should be possible to implement things like FuzzyClock in my configuration file without modifying xmobar at all! I should be able to use functions in my configuration file to do anything a Plugin can do now -- the output text should be composed of functions producing 'IO String'. Basically I think xmobar should be more like xmonad :)
Here's what a simple xmobar configuration file would look like in my ideal world (though getting rid of the separate commands list may be unrealistic because of threading+STM setup):
I think this is possible via some clever Applicative tricks, though I'm still pondering that.
import Xmobar import Xmobar.Monitors as Mon main = do xmobar $ Config { font = "-misc-fixed-*-*-*-*-10-*-*-*-*-*-*-*" , bgColor = "black" , fgColor = "grey" , position = Top , format = Format { , left = myCpu ++ " | " ++ myMemory where myCpu = "Cpu: " ++ (run 10 $ Mon.cpu [(3,"green"),(50,"red")]) ++ "%" myMemory = "Mem: " ++ (run 10 Mon.memUsedRatio) ++ "%" , middle = color "#aaa" stdinReader , right = color "aquamarine" $ run 10 myHaskellFunction } }
-- Fred Blasdel
Cheers, Spencer Janssen