X-Git-Url: https://git.rmz.io/my-scheme.git/blobdiff_plain/1823a25e280d35093e3689ebb5a86361dd222504..2c9201bc9abac31f46a43c621c4f47553d17c7a4:/app/Main.hs

diff --git a/app/Main.hs b/app/Main.hs
index c0766c1..233fa6c 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -1,7 +1,56 @@
 module Main where
+import Control.Monad
+import Text.ParserCombinators.Parsec hiding (spaces)
 import System.Environment
 
+data LispVal = Atom String
+             | List [LispVal]
+             | DottedList [LispVal] LispVal
+             | Number Integer
+             | String String
+             | Bool Bool
+             deriving Show
+
+symbol :: Parser Char
+symbol = oneOf "!#$%&|*+-/:<=>?@^_~"
+
+spaces :: Parser ()
+spaces = skipMany space
+
+parseString :: Parser LispVal
+parseString = do
+    char '"'
+    x <- many (noneOf "\"")
+    char '"'
+    return $ String x
+
+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 ds <- many1 digit
+                 let a = read ds
+                 return $ Number a
+
+parseExpr :: Parser LispVal
+parseExpr = parseString
+        <|> parseAtom
+        <|> parseNumber
+
+readExpr :: String -> String
+readExpr input = case parse parseExpr "lisp" input of
+    Left err -> "No match: " ++ show err
+    Right val -> "Found value: " ++ show val
+
 main :: IO ()
 main = do
-    args <- getArgs
-    putStrLn ("Hello, " ++ args !! 0)
+    args <- getLine
+    putStrLn (readExpr args)
+    main