6266c5d32f
Rename my //users directory and all places that refer to glittershark to grfn, including nix references and documentation. This may require some extra attention inside of gerrit's database after it lands to allow me to actually push things. Change-Id: I4728b7ec2c60024392c1c1fa6e0d4a59b3e266fa Reviewed-on: https://cl.tvl.fyi/c/depot/+/2933 Tested-by: BuildkiteCI Reviewed-by: tazjin <mail@tazj.in> Reviewed-by: lukegb <lukegb@tvl.fyi> Reviewed-by: glittershark <grfn@gws.fyi>
24 lines
924 B
Haskell
24 lines
924 B
Haskell
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module Xanthous.Util.Comonad
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( -- * Store comonad utils
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replace
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, current
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) where
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--------------------------------------------------------------------------------
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import Xanthous.Prelude
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--------------------------------------------------------------------------------
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import Control.Comonad.Store.Class
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--------------------------------------------------------------------------------
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-- | Replace the current position of a store comonad with a new value by
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-- comparing positions
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replace :: (Eq i, ComonadStore i w) => w a -> a -> w a
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replace w x = w =>> \w' -> if pos w' == pos w then x else extract w'
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{-# INLINE replace #-}
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-- | Lens into the current position of a store comonad.
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--
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-- current = lens extract replace
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current :: (Eq i, ComonadStore i w) => Lens' (w a) a
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current = lens extract replace
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{-# INLINE current #-}
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