Re: [xmonad] stupid newbie question about `removeKeysP`

5 May 2010

      On Wed, May 5, 2010 at 4:12 PM, Patrick Brisbin  wrote:
...
On 05/05/10 at 10:04pm, Anders Engström wrote:
...
Try this (untested code, note the '$'):
main = xmonad $ gnomeConfig
        {terminal       = "urxvtcd"
        }
        `removeKeysP` ["M-b","M-."]
Which is equivalent to, or a shorthand for:
main = xmonad (gnomeConfig
        {terminal       = "urxvtcd"
        }
        `removeKeysP` ["M-b","M-."])
`removeKeysP` is in your code applied to the arguments:
arg1: xmonad gnomeConfig {terminal       = "urxvtcd"}
arg2: ["M-b","M-."]
Hope that helps.
/Anders
On Wed, May 5, 2010 at 21:37, Jonas Bygdén  wrote:
...
Hi,
I'm slowly going nuts here.
This is my complete xmonad.hs file:
-------------------------------------------
import XMonad
import XMonad.Config.Gnome
import XMonad.Util.EZConfig
main = xmonad gnomeConfig
        {terminal       = "urxvtcd"
        }
        `removeKeysP` ["M-b","M-."]
-------------------------------------------
And when I try to use it I get these errors:
-------------------------------------------
xmonad.hs:5:7:
    Couldn't match expected type `XConfig l'
           against inferred type `IO ()'
    In the first argument of `removeKeysP', namely
        `xmonad (gnomeConfig {terminal = "urxvtcd"})'
    In the expression:
          xmonad (gnomeConfig {terminal = "urxvtcd"})
        `removeKeysP`
          ["M-b", "M-."]
    In the definition of `main':
        main = xmonad (gnomeConfig {terminal = "urxvtcd"})
             `removeKeysP`
               ["M-b", "M-."]
Please check the file for errors.
-------------------------------------------
Where have I gone wrong?
/Jonas
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Don't you still need a 'do' somewhere in there?
 main = do
   xmonad $ gnomeConfig
   { terminal = "urxvtcd"
   }
   `removeKeysP` ["M-b", "M-."]
should compile.
I think all on one line looks more readable though:
 main = do
   xmonad $ gnomeConfig { terminal = "urxvtcd" } `removeKeysP` ["M-b", "M-."]
Apologies if this doesn't work, I haven't compiled it myself.
No; do-notation is only necessary if you're using any syntax like the
let bindings or <- or newlines - stuff which desugars to use of
monadic functions like >> or >>=. This is all straight function calls.

Hlint will even tell you that the do is unnecessary:

hlint foo.hs
foo.hs:1:9: Error: Redundant do
Found:
  do xmonad $
       gnomeConfig{terminal = "urxvtcd"} `removeKeysP` ["M-b", "M-."]
Why not:
  xmonad $
    gnomeConfig{terminal = "urxvtcd"} `removeKeysP` ["M-b", "M-."]

Found 1 suggestion (1 error)

-- 
gwern

Re: [xmonad] stupid newbie question about `removeKeysP`

Gwern Branwen