[Xmonad] darcs patch: simplify shift, removing unneeded check.

[David Roundy]

On Tue, Jun 26, 2007 at 02:13:46PM +1000, Donald Bruce Stewart wrote:
> droundy:
> > Just a little cleanup...
> > 
> > Sun Jun 24 08:08:51 PDT 2007  David Roundy <droundy at darcs.net>
> >   * simplify shift, removing unneeded check.
> > 
> 
> Content-Description: A darcs patch for your repository!
> > 
> > New patches:
> > 
> > [simplify shift, removing unneeded check.
> > David Roundy <droundy at darcs.net>**20070624150851] 
> > <
> > > {
> > hunk ./StackSet.hs 479
> >  -- The actual focused workspace doesn't change. If there is -- no
> >  -- element on the current stack, the original stackSet is returned.
> >  --
> > -shift :: (Ord a, Eq s, Integral i) => i -> StackSet i a s -> StackSet i a s
> > -shift n s = if and [n >= 0,n `tagMember` s, n /= tag (workspace (current s))]
> > +shift :: (Ord a, Eq s, Eq i) => i -> StackSet i a s -> StackSet i a s
> > +shift n s = if n `tagMember` s && n /= tag (workspace (current s))
> >              then maybe s go (peek s) else s
> >      where go w = foldr ($) s [view (tag (workspace (current s))),insertUp w,view n,delete w]
> >                             --  ^^ poor man's state monad :-)
> > }
> 
> 
> Incorrect type ?
> 
> /home/dons/bin/ghc -I/usr/obj/cabal -o /usr/obj/cabal/xmonad/xmonad --make -hide-all-packages -i -i/usr/obj/cabal/autogen -i. -odir /usr/obj/cabal/xmonad/xmonad-tmp -hidir /usr/obj/cabal/xmonad/xmonad-tmp -package base-2.0 -package X11-1.2.2 -package X11-extras-0.2 -package mtl-1.0 -package unix-1.0 -funbox-strict-fields -O2 -fasm -Wall -optl-Wl,-s -fglasgow-exts Main.hs
> [1 of 6] Compiling StackSet         ( StackSet.hs, /usr/obj/cabal/xmonad/xmonad-tmp/StackSet.o )
> 
> StackSet.hs:487:83:
>     Could not deduce (Integral i) from the context (Ord a, Eq s, Eq i)
>       arising from use of `delete' at StackSet.hs:487:83-90
>     Possible fix: add (Integral i) to the type signature(s) for `shift'
>     In the expression: delete w
>     In the third argument of `foldr', namely
>     `[view (tag (workspace (current s))), insertUp w, view n,
>       delete w]'
>     In the expression:
>     foldr
>       ($)
>       s
>       [view (tag (workspace (current s))), insertUp w, view n, delete w]
> 
> 
> Or it depends on your 'delete' patch?

I guess it must depend on my delete patch.  It compiles for me.
-- 
David Roundy
http://www.darcs.net