shithub: MicroHs

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Add helper class for interactive top level

--- a/lib/System/IO.hs

+++ b/lib/System/IO.hs

@@ -177,3 +177,15 @@

 -- MicroHs is always in binary mode

 hSetBinaryMode :: Handle -> Bool -> IO ()

 hSetBinaryMode _ _ = return ()

+

+--------

+

+-- Helper for interactive system

+class PrintOrRun a where

+  printOrRun :: a -> IO ()

+

+instance PrintOrRun (IO ()) where

+  printOrRun a = a

+

+instance forall a . Show a => PrintOrRun a where

+  printOrRun a = putStrLn (show a)

--- a/src/MicroHs/Interactive.hs

+++ b/src/MicroHs/Interactive.hs

@@ -109,7 +109,7 @@

 itName = "_it"

 mkIt :: String -> String

-mkIt l = itName ++ " :: IO ()\n" ++ itName ++ " = print (" ++ l ++ ")\n"

+mkIt l = itName ++ " :: IO ()\n" ++ itName ++ " = printOrRun (" ++ l ++ ")\n"

 err :: Exn -> IO ()

 err (Exn s) = putStrLn $ "Error: " ++ s

-- 

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