stupid newbie question about `removeKeysP`

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Jonas Bygdén

5 May 2010 5 May '10

3:37 p.m.

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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Anders Engström

5 May 5 May

4:04 p.m.

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 _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

Patrick Brisbin

4:12 p.m.

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 _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

_______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

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. -- patrick brisbin

Anders Engström

4:26 p.m.

Actually, you don't need "do". Since xmonad with argument applied becomes IO () and main is IO (). When you only have one statement after do, it is an identity operation. Actually, I cheated and looked at the docs which had this example: main = xmonad $ defaultConfig { terminal = "urxvt" } `removeKeysP` ["M-S-" ++ [n] | n <- ['1'..'9']] On Wed, May 5, 2010 at 22:12, 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 _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

_______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

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.

-- patrick brisbin _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

Patrick Brisbin

4:29 p.m.

On 05/05/10 at 10:26pm, Anders Engström wrote:

...

Actually, you don't need "do". Since xmonad with argument applied becomes IO () and main is IO (). When you only have one statement after do, it is an identity operation.

Thanks. Though I don't /completely/ understand it, I'll try to remember it :). -- patrick brisbin

Jonas Bygdén

4:40 p.m.

Thanks Anders, I've been staring myself blind at that very example that you included here from the docs and couldn't understand what I did wrong - until you told me the $ was missing. Thanks again. 2010/5/5 Anders Engström

...

Actually, you don't need "do". Since xmonad with argument applied becomes IO () and main is IO (). When you only have one statement after do, it is an identity operation.

Actually, I cheated and looked at the docs which had this example: main = xmonad $ defaultConfig { terminal = "urxvt" } `removeKeysP` ["M-S-" ++ [n] | n <- ['1'..'9']]

On Wed, May 5, 2010 at 22:12, 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 _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

_______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

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.

-- patrick brisbin _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

_______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

Gwern Branwen

4:31 p.m.

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 _______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

_______________________________________________ xmonad mailing list xmonad@haskell.org http://www.haskell.org/mailman/listinfo/xmonad

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

Gwern Branwen

4:06 p.m.

On Wed, May 5, 2010 at 3:37 PM, Jonas Bygdén wrote:

...

import XMonad import XMonad.Config.Gnome import XMonad.Util.EZConfig main = xmonad gnomeConfig {terminal = "urxvtcd" } `removeKeysP` ["M-b","M-."]

When in doubt, parenthesize. ---- main = xmonad (gnomeConfig {terminal = "urxvtcd" }) `removeKeysP` ["M-b","M-."] /home/gwern/foo.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-."] ---- ---- import XMonad import XMonad.Config.Gnome import XMonad.Util.EZConfig main = xmonad ((gnomeConfig {terminal = "urxvtcd" }) `removeKeysP` ["M-b","M-."]) /home/gwern/foo.hs:5:0: Warning: Definition but no type signature for `main' Inferred type: main :: IO () ---- Do you understand why? -- gwern

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Anders Engström
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stupid newbie question about `removeKeysP`

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