On Thu, Aug 16, 2007 at 05:52:37AM +0000, Xavier Maillard wrote:

It helped but I now have this :

[20 of 21] Compiling Config ( Config.hs, dist/build/xmonad/xmonad-tmp/Config.o )

Config.hs:171:30: No instance for (Integral [WorkspaceId]) arising from use of `fromIntegral' at Config.hs:171:30-52 Possible fix: add an instance declaration for (Integral [WorkspaceId]) In the first argument of `(-)', namely `fromIntegral workspaces' In the expression: (fromIntegral workspaces) - 1 In the first argument of `zip', namely `[0 .. (fromIntegral workspaces) - 1]'

You are using a function that is not working after the latest changes in XMonad (take into account that the darcs version, while very stable, still is a work in progress and sometimes the Contrib modules are a bit out of sync). We have 2 ways now: 1. the best thing is to start with a new, fresh Config file: save the one you are working on and issu the darcs revert command: darcs revert Config.hs Then rewrite your personalization from scratch and see what fails. 2. send here the offending lines (arounf Config line 170), so that I can understand the specific issue with the offending function and try to give you an answer. Let me know. Andrea

Hi Xavier, only as a side-note. Although I use a heavily modified Config.hs (different key bindings, lots of extensions) it's quite easy for me to sync changes in with Emacs' `ediff'. So if xmonad fails to compile the first thing I do is `ediff' between my Config.hs and the original one. Bye, Tassilo -- If programmers deserve to be rewarded for creating innovative programs, by the same token they deserve to be punished if they restrict the use of these programs. (Richard M. Stallman)

maillaxa:

Hello Tassilo,

Tassilo Horn writes:

...

only as a side-note. Although I use a heavily modified Config.hs (different key bindings, lots of extensions) it's quite easy for me to sync changes in with Emacs' `ediff'. So if xmonad fails to compile the first thing I do is `ediff' between my Config.hs and the original one.

Although I agree with you, it would not help me since I am really not a haskell programer *at all* :) I feel so lost reading haskell code that I am still asking if xmonad is really the way to go for me :/ On the other part, xmonad works very well for me and I just love it so, I keep trying :)

It is good to learn new things! You'll pick it up in no time, I'm sure :) If any of the code is hard to understand in the Config file, drop by the #xmonad @ freenode irc channel, and we can walk through it together. -- Don

On Fri, Aug 17, 2007 at 10:38:12AM +0200, Kai Grossjohann wrote:

The part that I'm having trouble with is monads and the associated operators (liftm comes to mind, it seems to be somehow related). I read Hal Daume's tutorial. Do you have advice what else I can read to grok?

(And I'm having trouble to understand the relationship between "<-" and "=". Apparently, "<-" somehow implies that "statements" are "executed" in some order. But Haskell tries really hard to hide the fact that there are statements and that there is such as thing as execution. As Haskell is based on lambda calculus, I am not surprised -- there are no statements and there is no order of execution in lambda calculus. So Haskell tries so hard to hide them that I can't find them...)

Hi Kay, may I point you to this? http://www.haskell.org/haskellwiki/The_Monadic_Way I wrote it when I was trying to grasp monads myself, with the hope to provide newcomers with a helpful guide through stuff like <-, >> and

...

=.

A monad is just a way to nest anonymous functions so that bound variables (<-) can be later used by other (nested) anonymous functions. And by nesting functions you can simulate an order of execution. The complexity of this operation is hidden by the "do" notation, where every new line is indeed an anonymous function. The advise I can give you is to try to re-implement monads (and later arrows, and so on), by reading the papers that discovered them. For monads I suggest this paper: P. Wadler, Monads for functional programming. http://homepages.inf.ed.ac.uk/wadler/papers/marktoberdorf/baastad.pdf This is how I came to understand monads. Hope this helps Andrea

tassilo:

Hi Xavier,

only as a side-note. Although I use a heavily modified Config.hs (different key bindings, lots of extensions) it's quite easy for me to sync changes in with Emacs' `ediff'. So if xmonad fails to compile the first thing I do is `ediff' between my Config.hs and the original one.

Bye, Tassilo

That's a good idea. I used to use vimdiff when diffing dwm config.h files. My Config.hs is very minimally modified, so its not so much of an issue now. -- Don