MultiToggle + Decorations breaks upgrading to 0.10
I just upgraded from 0.9 to 0.10 and had to comment out the following to get my xmonad.hs to compile: data DECORATIONS = DECORATIONS deriving (Read, Show, Eq, Typeable) instance MultiToggle.Transformer DECORATIONS Window where transform _ x k = k (simpleDeco shrinkText (defaultTheme { decoWidth = 9999999, fontName = "-*-helvetica-bold-r-*-*-14-*-*-*-*-*-*-*", inactiveColor = "black", activeColor = "black", activeTextColor = "red", inactiveTextColor = "green" } ) x) Which gives me this glorious error: xmonad.hs:10:16: Warning: -fglasgow-exts is deprecated: Use individual extensions instead xmonad.hs:247:36: Couldn't match type `b' with `(XMonad.Layout.LayoutModifier.ModifiedLayout (XMonad.Layout.Decoration.Decoration SimpleDecoration XMonad.Layout.Decoration.DefaultShrinker) l GHC.Word.Word64 -> l GHC.Word.Word64) -> b' `b' is a rigid type variable bound by the type signature for transform :: LayoutClass l Window => DECORATIONS -> l Window -> (forall (l' :: * -> *). LayoutClass l' Window => l' Window -> (l' Window -> l Window) -> b) -> b at xmonad.hs:247:18 In the return type of a call of `k' Probable cause: `k' is applied to too few arguments In the expression: k (simpleDeco shrinkText (defaultTheme {decoWidth = 9999999, fontName = "-*-helvetica-bold-r-*-*-14-*-*-*-*-*-*-*", inactiveColor = "black", activeColor = "black", activeTextColor = "red", inactiveTextColor = "green"}) x) In an equation for `transform': transform _ x k = k (simpleDeco shrinkText (defaultTheme {decoWidth = 9999999, fontName = "-*-helvetica-bold-r-*-*-14-*-*-*-*-*-*-*", inactiveColor = "black", activeColor = "black", activeTextColor = "red", inactiveTextColor = "green"}) x) I see that it's complaining that k is applied to too few arguments, so I looked in the docs for MultiToggle and in their example it looks like k takes what looks like a lambda (I'm actually confused by the syntax, I've never seen parens around a lambda parameter) as a second argument now for some reason: data MIRROR = MIRROR deriving (Read, Show, Eq, Typeable) instance Transformer MIRROR Window where transform _ x k = k (Mirror x) (\(Mirror x') -> x') But I'm too much of a Haskell newb to adapt my decoration snippet for that. Help? Thanks, Joe G.
On Sat, Sep 22, 2012 at 10:18:15AM -0500, Joseph Garvin wrote:
I see that it's complaining that k is applied to too few arguments, so I looked in the docs for MultiToggle and in their example it looks like k takes what looks like a lambda (I'm actually confused by the syntax, I've never seen parens around a lambda parameter) as a second argument now for some reason:
The argument of a lambda may be an arbitrary pattern, just like in a function definition. Patterns other than single variables usually need to be surrounded by parentheses, since otherwise they will parse as multiple arguments. For example, foo (Just x) = x \(Just x) -> x
data MIRROR = MIRROR deriving (Read, Show, Eq, Typeable) instance Transformer MIRROR Window where transform _ x k = k (Mirror x) (\(Mirror x') -> x')
It looks like the second argument to k is a function which removes the transformation from the layout. For decoration, it looks like you want (\(ModifiedLayout _ x') -> x') In fact, that will work for the vast majority of transformations, which are mostly implemented using a layout modifier. Mirror is special because it's built into the xmonad core. -Brent
participants (2)
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Brent Yorgey -
Joseph Garvin