parser.hs

-- Solution to Stanford Compilers Course.
-- (c) Copyright 2012 Michael Starzinger. All Rights Reserved.

module Main (main) where
import CoolParser (Result(..),parse)
import CoolPrinter (prettyProgram)
import System.Console.GetOpt
import System.Environment (getArgs)

-- This is a description of the command line options to this program.
options :: [OptDescr ()]
options = [
		Option ['g'] ["garbage"] (NoArg ()) "gabage collection",
		Option ['o'] ["output"] (ReqArg (const ()) "FILE") "output file"
	]

-- This is the main program entry for the parser used as a standalone
-- program that reads input from a file and prints resulting AST.
main = do
	args <- getArgs
	filename <- do
		case getOpt RequireOrder options args of
			(_,[x],[]) -> return x
			(_,___,__) -> error $ usageInfo "Invalid usage." options
	input <- readFile filename
	case parse input of
		(Program p)       -> prettyProgram p
		(LexerError l m)  -> printLexerError filename l m
		(ParserError l t) -> printParseError filename l t
	where
		printLexerError f l m = do
			putStr $ (show f) ++ ", line " ++ (show l) ++ ": lexical error " ++ (show m) ++ "\n"
			putStr $ "Compilation halted due to lex and parse errors\n"
		printParseError f l t = do
			putStr $ (show f) ++ ", line " ++ (show l) ++ ": syntax error at or near " ++ (show t) ++ "\n"
			putStr $ "Compilation halted due to lex and parse errors\n"