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| author | Michael G. Sloan <mgsloan@gmail.com> | 2007-07-22 22:53:37 +0200 |
|---|---|---|
| committer | Michael G. Sloan <mgsloan@gmail.com> | 2007-07-22 22:53:37 +0200 |
| commit | 3db17331b1d1308f8d9ceb336d1bfef7a91fadc5 (patch) | |
| tree | c40f28b3da216af314feed897813a8d0ea8814d5 /StackSet.hs | |
| parent | e0f1d01bd6551dd3282a580c83fa359d2348320e (diff) | |
| download | metatile-3db17331b1d1308f8d9ceb336d1bfef7a91fadc5.tar metatile-3db17331b1d1308f8d9ceb336d1bfef7a91fadc5.zip | |
Cleanup of shift code
darcs-hash:20070722205337-0d649-35419b898df5fc30d9a48bde46f8ede66e39c009
Diffstat (limited to 'StackSet.hs')
| -rw-r--r-- | StackSet.hs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/StackSet.hs b/StackSet.hs index 037b124..265359c 100644 --- a/StackSet.hs +++ b/StackSet.hs @@ -487,7 +487,7 @@ swapMaster = modify' $ \c -> case c of -- element on the current stack, the original stackSet is returned. -- shift :: (Ord a, Eq s, Integral i) => i -> StackSet i a s sd -> StackSet i a s sd -shift n s = if and [n >= 0,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 :-) +shift n s = if n >= 0 && n `tagMember` s && n /= curtag + then maybe s go (peek s) else s + where go w = view curtag . insertUp w . view n . delete w $ s + curtag = tag (workspace (current s)) |