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{-# LANGUAGE GADTs, EmptyDataDecls, TypeFamilies, TypeOperators, DataKinds, FlexibleInstances #-}
{- Defines a C-like printf function using DataKinds extensions. -}
module T13659 where
import Data.Kind (Type)
-- format string parameterized by a list of types
data Format (fmt :: [Type]) where
X :: Format '[] -- empty string, i.e. ""
L :: a -> String -> Format '[] -- string literal, e.g. "hello"
S :: a -> Format '[String] -- "%s"
I :: Format a -> Format '[Int, a] -- "%d"
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