1 files changed, 40 insertions, 0 deletions
diff --git a/src/Phi/Panel.hs b/src/Phi/Panel.hs
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+++ b/src/Phi/Panel.hs
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+{-# LANGUAGE ExistentialQuantification #-}
+
+module Phi.Panel ( Panel(..)
+                 , PanelClass(..)
+                 , (<~>)
+                 , separator
+                 ) where
+
+import Data.Function
+
+class PanelClass a where
+  minSize :: a -> Int
+  
+  weight :: a -> Float
+  weight _ = 0
+
+data Panel = forall a. PanelClass a => Panel a
+
+instance PanelClass Panel where
+  minSize (Panel p) = minSize p
+  weight (Panel p) = weight p
+
+data CompoundPanel = CompoundPanel Panel Panel
+
+instance PanelClass CompoundPanel where
+  minSize (CompoundPanel a b) = ((+) `on` minSize) a b
+  weight (CompoundPanel a b) = ((+) `on` weight) a b
+
+(<~>) :: Panel -> Panel -> Panel
+a <~> b = Panel $ CompoundPanel a b
+
+
+data Separator = Separator Int Float
+
+instance PanelClass Separator where
+  minSize (Separator s _) = s
+  weight (Separator _ w) = w
+
+separator :: Int -> Float -> Panel
+separator s w = Panel $ Separator s w