X-Git-Url: https://git.rmz.io/my-scheme.git/blobdiff_plain/369fde6e9fc7f5ddd28d83e34da21624cb4c2c7c..fabc3d8bdaef310b2f18bc53735ad7ee53518822:/app/Main.hs?ds=inline

diff --git a/app/Main.hs b/app/Main.hs
index c71126b..1495605 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -9,6 +9,7 @@ data LispVal = Atom String
              | DottedList [LispVal] LispVal
              | Number Integer
              | String String
+             | Character Char
              | Bool Bool
              deriving Show
 
@@ -18,21 +19,29 @@ symbol = oneOf "!#$%&|*+-/:<=>?@^_~"
 spaces :: Parser ()
 spaces = skipMany space
 
+nonPrintableChar :: Parser Char
+nonPrintableChar = do c <- char '\\' >> oneOf "\\nrtf"
+                      return $ case c of '\\' -> '\\'
+                                         'n'  -> '\n'
+                                         'r'  -> '\r'
+                                         't'  -> '\t'
+                                         'f'  -> '\f'
+
+parseCharacter :: Parser LispVal
+parseCharacter = do char '\''
+                    c <- noneOf ['\\', '\''] <|> try singleQuote <|> try nonPrintableChar
+                    char '\''
+                    return $ Character c
+                 where
+                    singleQuote = char '\\' >> char '\''
+
 parseString :: Parser LispVal
 parseString = do char '"'
                  x <- many innerChar
                  char '"'
                  return $ String x
-              where innerChar = noneOf ['\\', '\"'] <|> escapeChar
-                    escapeChar = do char '\\'
-                                    c <- oneOf ['\"', '\\', 'n', 'r', 't', 'f']
-                                    return $ case c of
-                                                '\"' -> '\"'
-                                                '\\' -> '\\'
-                                                'n'  -> '\n'
-                                                'r'  -> '\r'
-                                                't'  -> '\t'
-                                                'f'  -> '\f'
+              where innerChar = noneOf ['\\', '"'] <|> try doubleQuote <|> try nonPrintableChar
+                    doubleQuote = char '\\' >> char '"'
 
 parseAtom :: Parser LispVal
 parseAtom = do
@@ -56,15 +65,44 @@ parseNumber = do toNum <- radix
                                            'o' -> readOct
                                            'b' -> readInt 2 (\x -> elem x "01") (read . (:[]))
 
+parseList :: Parser LispVal
+parseList = liftM List $ sepBy parseExpr spaces
+
+parseDottedList :: Parser LispVal
+parseDottedList = do
+    head <- endBy parseExpr spaces
+    tail <- char '.' >> spaces >> parseExpr
+    return $ DottedList head tail
+
+parseQuoted :: Parser LispVal
+parseQuoted = do
+    char '\''
+    x <- parseExpr
+    return $ List [Atom "quote", x]
+
 parseExpr :: Parser LispVal
 parseExpr = parseString
         <|> parseNumber
         <|> parseAtom
+        <|> try parseCharacter
+        <|> parseQuoted
+        <|> do char '('
+               x <- try parseList <|> parseDottedList
+               char ')'
+               return x
 
 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
+
+showVal :: LispVal -> String
+showVal (Atom atom)   = atom
+showVal (Number n)    = show n
+showVal (String str)  = "\"" ++ str ++ "\""
+showVal (Character c) = "'" ++ [c] ++ "'"
+showVal (Bool True)   = "#t"
+showVal (Bool False)  = "#f"
 
 main :: IO ()
 main = do