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{-# LANGUAGE DataKinds #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedLabels #-}
{-# LANGUAGE MagicHash #-}
import Data.Foldable (traverse_)
import Data.Proxy (Proxy(..))
import GHC.OverloadedLabels (IsLabel(..))
import GHC.TypeLits (KnownSymbol, symbolVal)
import GHC.Prim (Addr#)
instance KnownSymbol symbol => IsLabel symbol String where
fromLabel = symbolVal (Proxy :: Proxy symbol)
(#), (#.) :: String -> Int -> String
(#) _ i = show i
_ #. i = show i
f :: Addr# -> Int -> String
f _ i = show i
main :: IO ()
main = traverse_ putStrLn
[ #a
, #number17
, #do
, #type
, #Foo
, #3
, #"199.4"
, #17a23b
, #f'a'
, #'a'
, #'
, #''notTHSplice
, #"..."
, #привет
, #こんにちは
, #"3"
, #":"
, #"Foo"
, #"The quick brown fox"
, #"\""
, (++) #hello#world
, (++) #"hello"#"world"
, #"hello"# 1 -- equivalent to `(fromLabel @"hello") # 1`
, f "hello"#2 -- equivalent to `f ("hello"# :: Addr#) 2`
]
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