fxsk.hs

-- fxsk
--
-- A simple brainfuck to c++ cross-compiler written in Haskell
module Main where
import System( getArgs )

-- Define types for lexical analyzer
type Token = Char

-- Function: extractToken
extractToken :: Char -> [Token]
extractToken ch = do 
                  let validTokens = ['>', '<', '+', '-', '.', ',', '[', ']']
                  if ch `elem` validTokens
                    then [ch]
                    else []

-- Function: bfLex
bfLex :: [Char] -> [Token]
bfLex (ch:xs) = (extractToken ch) ++ (bfLex xs)
bfLex []      = []

-- Function: emitCodeFor
emitCodeFor :: Token -> String
emitCodeFor t = case t of
                  '>' -> "++ptr;"
                  '<' -> "--ptr;"
                  '+' -> "++*ptr;"
                  '-' -> "--*ptr;"
                  '.' -> "cout << *ptr;"
                  ',' -> "cin >> *ptr;"
                  '[' -> "while (*ptr) {"
                  ']' -> "}"
                  _   -> "*BAD TOKEN*"

-- Function: compile
compile :: [Token] -> String
compile (t:xs) = (emitCodeFor t) ++ (compile xs)
compile []     = ""

main = putStrLn (compile (bfLex "a++[+,]"))