X-Git-Url: https://git.rmz.io/my-scheme.git/blobdiff_plain/429ac1845f1b93f54bca8511a4efbf8cbcbb9bf3..369fde6e9fc7f5ddd28d83e34da21624cb4c2c7c:/app/Main.hs

diff --git a/app/Main.hs b/app/Main.hs
index 8520891..c71126b 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -1,6 +1,16 @@
 module Main where
+import Control.Monad
 import Text.ParserCombinators.Parsec hiding (spaces)
 import System.Environment
+import Numeric
+
+data LispVal = Atom String
+             | List [LispVal]
+             | DottedList [LispVal] LispVal
+             | Number Integer
+             | String String
+             | Bool Bool
+             deriving Show
 
 symbol :: Parser Char
 symbol = oneOf "!#$%&|*+-/:<=>?@^_~"
@@ -8,12 +18,56 @@ symbol = oneOf "!#$%&|*+-/:<=>?@^_~"
 spaces :: Parser ()
 spaces = skipMany space
 
+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'
+
+parseAtom :: Parser LispVal
+parseAtom = do
+    a <- letter <|> symbol
+    b <- many (letter <|> digit <|> symbol)
+    let atom = a:b
+    return $ case atom of
+                "#t" -> Bool True
+                "#f" -> Bool False
+                _    -> Atom atom
+
+parseNumber :: Parser LispVal
+parseNumber = do toNum <- radix
+                 ds <- many1 digit
+                 let ((a,_):_) = toNum ds
+                 return $ Number a
+              where radix = do r <- try (char '#' >> oneOf "bodx") <|> return 'd'
+                               return $ case r of
+                                           'd' -> readDec
+                                           'x' -> readHex
+                                           'o' -> readOct
+                                           'b' -> readInt 2 (\x -> elem x "01") (read . (:[]))
+
+parseExpr :: Parser LispVal
+parseExpr = parseString
+        <|> parseNumber
+        <|> parseAtom
+
 readExpr :: String -> String
-readExpr input = case parse (spaces >> symbol) "lisp" input of
+readExpr input = case parse parseExpr "lisp" input of
     Left err -> "No match: " ++ show err
-    Right val -> "Found value"
+    Right val -> "Found value: " ++ show val
 
 main :: IO ()
 main = do
     args <- getLine
     putStrLn (readExpr args)
+    main