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khibino/format.hs

Created August 2, 2022 04:06
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format.hs
-- printf like function, formatting package method
newtype Format r a = Format ((ShowS -> r) -> a)
string :: Format r (String -> r)
string = Format $ \k s -> k (s ++)
int :: Format r (Int -> r)
int = Format $ \k i -> k (show i ++)
(%) :: Format r a -> Format r' r -> Format r' a
Format x1 % Format x2 = Format $ \k -> x1 $ \s1 -> x2 $ \s2 -> k (s1 . s2)
infixr 9 %
lit :: String -> Format r r
lit s = Format ($ (s ++))
format :: Format String a -> a
format (Format x) = x ($ "")
exampleFmt :: Format r (String -> Int -> r)
exampleFmt = lit "example string: " % string % lit ", example int: " % int
example :: String
example = format exampleFmt "abc" 3
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