46 lines
1.1 KiB
Haskell
46 lines
1.1 KiB
Haskell
{-# LANGUAGE TypeSynonymInstances #-}
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{-# LANGUAGE FlexibleInstances #-}
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module Affection.Property
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( Props
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, prop
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, props
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) where
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import qualified GEGL as G
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import qualified BABL as B
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import Control.Monad.State.Lazy
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import Foreign.Ptr (Ptr)
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type Props a = State [G.Property] a
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props :: Props a -> [G.Property]
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props = flip execState []
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prop :: IsPropertyValue v => String -> v -> Props ()
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prop k v = do
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ps <- get
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put $ G.Property k (toPropertyValue v) : ps
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class IsPropertyValue v where
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toPropertyValue :: v -> G.PropertyValue
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instance IsPropertyValue Int where
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toPropertyValue = G.PropertyInt
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instance IsPropertyValue String where
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toPropertyValue = G.PropertyString
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instance IsPropertyValue Double where
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toPropertyValue = G.PropertyDouble
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instance IsPropertyValue G.Color where
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toPropertyValue = G.PropertyColor
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instance IsPropertyValue B.PixelFormat where
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toPropertyValue = G.PropertyFormat
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instance IsPropertyValue G.GeglBuffer where
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toPropertyValue = G.PropertyBuffer
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instance IsPropertyValue (Ptr ()) where
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toPropertyValue = G.PropertyPointer
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