{-# LANGUAGE NamedFieldPuns #-}
module Main where
import Data.Functor ((<$))
import Data.List.Split (chunk)
import qualified Data.Vector.Unboxed as V
import Language.ArrayForth.Interpreter (eval, runNativeProgram)
import Language.ArrayForth.Parse (isNumber)
import Language.ArrayForth.Program (readProgram, toNative)
import Language.ArrayForth.State (Memory (..), State (..),
setProgram, startState)
import System.Environment (getArgs)
import System.IO (hFlush, stdout)
import Text.Printf (printf)
main :: IO ()
main = do args <- getArgs
case args of
[] -> repl
[file] -> readFile file >>= print . runNativeProgram startState . read
_ -> putStrLn $ "Too many arguments!"
repl :: IO ()
repl = putStrLn errorMessage >> go (0, startState)
where errorMessage = "Type :help for a list of possible command."
go (loc, state) = do
inp <- putStr "λ>" >> hFlush stdout >> getLine
case inp of
":" -> do
putStrLn ("Please specify a valid command. " ++ errorMessage)
go (loc, state)
':' : commands -> let command : args = words commands in
run command args >>= go
program -> execute $ readProgram program
where helpMessage = unlines $ [
":help — list the possible commands",
":reset — reset all the registers and memory to 0",
":p — print the value of the p register (the program counter)",
":p <n> — set the p register to the given address n; a manual jump instruction",
":memory — print all of the memory in a reasonably easy to read format"]
execute (Left err) = print err >> go (loc, state)
execute (Right program) = print res >> go (p, res)
where res@State {p} = eval $ setProgram loc (toNative program) state
run "reset" _ = (0, startState) <$ print startState
run "p" [] = (loc, state) <$ print (p state)
run "p" args
| not (isNumber $ head args) =
(loc, state) <$ putStrLn "Invalid arguments!"
| otherwise = let n = read $ head args in
(n, state { p = n }) <$ print state { p = n }
run cmd args = (loc, state) <$ continue cmd args
continue "help" _ = putStr helpMessage
continue "memory" _ = mapM_ print . chunk 8 . V.toList . ram $ memory state
continue cmd _ = printf "Unknown command `%s'!\n%s" cmd errorMessage