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{- |
Module : Data.Graph.Inductive.Proxy
Description : Proxy type for graph tests
Copyright : (c) Ivan Lazar Miljenovic
License : BSD3
Maintainer : Ivan.Miljenovic@gmail.com
To avoid relying upon a newer version of base, this defines a
custom Proxy type and convenience functions.
-}
module Data.Graph.Inductive.Proxy where
import qualified Data.Graph.Inductive.PatriciaTree as P
import qualified Data.Graph.Inductive.Tree as T
import Data.Word (Word8)
-- -----------------------------------------------------------------------------
-- By default, we want to avoid using 'Int' to avoid clashing with the
-- 'Node' type. Don't want to use a floating type in case of
-- potential Eq problems.
type GraphType gr = gr Char Word8
type GraphProxy gr = Proxy (GraphType gr)
type TreeP = GraphProxy T.Gr
type PatriciaTreeP = GraphProxy P.Gr
-- Not using the Data.Proxy module so this also works with older
-- versions of GHC.
data Proxy a = Proxy
deriving (Eq, Ord, Show, Read)
asProxyTypeOf :: a -> Proxy a -> a
asProxyTypeOf a _ = a
withProxy :: Proxy a -> a -> a
withProxy _ a = a
asProxyGraphTypeOf :: gr () () -> Proxy (gr a b) -> gr () ()
asProxyGraphTypeOf gr _ = gr
|
