Sample.hs

module Ansiform.Internal.Sample where

--------------------------------------------------------------------------------

-- | Inspection helpers for debugging values.
class Sample a where
    sample :: a -> IO ()
    sample x = putStrLn $ sampleShow 0 x

    sampleShow :: Int -> a -> String

sampleFormat :: (Sample a) => String -> Int -> a -> String
sampleFormat s n c = s ++ "\n" ++ sampleShow n c

-- Basic Instances
--------------------------------------------------------------------------------

instance (Sample a, Show a) => Sample (Maybe a) where
    sampleShow _ Nothing = "Nothing"
    sampleShow _ (Just a) = "Just " ++ sampleShow 0 a

instance (Sample a) => Sample [a] where
    sample xs = putStrLn $ sampleShow (-1) xs
    sampleShow n xs | n < 0 = showCList 0 | otherwise = showCList (n + 2)
      where
        showCList = showContentList (zip xs [0 ..])

-- Support function to assist in showing list of content types.
showContentList :: (Sample a) => [(a, Int)] -> Int -> String
showContentList [] _ = ""
showContentList ((i, 0) : is) n = showSpaces n ++ sampleShow n i ++ showContentList is n
showContentList ((i, _) : is) n = "\n" ++ showSpaces n ++ sampleShow n i ++ showContentList is n

showSpaces :: Int -> String
showSpaces n = replicate n ' '