X-Git-Url: https://git.rmz.io/my-scheme.git/blobdiff_plain/ae8ff4666104497a9d6f1d89f044bbb202f10c71..refs/heads/master:/app/Main.hs

diff --git a/app/Main.hs b/app/Main.hs
index fb8294a..78f37ea 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -11,7 +11,6 @@ data LispVal = Atom String
              | String String
              | Character Char
              | Bool Bool
-             deriving Show
 
 symbol :: Parser Char
 symbol = oneOf "!#$%&|*+-/:<=>?@^_~"
@@ -94,7 +93,21 @@ parseExpr = parseString
 readExpr :: String -> String
 readExpr input = case parse parseExpr "lisp" input of
     Left err -> "No match: " ++ show err
-    Right val -> "Found value: " ++ show val
+    Right val -> "Found value: " ++ showVal val
+
+instance Show LispVal where show = showVal
+showVal :: LispVal -> String
+showVal (Atom atom)   = atom
+showVal (List list)   = "(" ++ unwordsList list ++ ")"
+showVal (DottedList head tail)   = "(" ++ unwordsList head ++ " . " ++ showVal tail ++ ")"
+showVal (Number n)    = show n
+showVal (String str)  = "\"" ++ str ++ "\""
+showVal (Character c) = "'" ++ [c] ++ "'"
+showVal (Bool True)   = "#t"
+showVal (Bool False)  = "#f"
+
+unwordsList :: [LispVal] -> String
+unwordsList = unwords . map showVal
 
 main :: IO ()
 main = do