import Language.Python.Common

import Language.Python.Version2 as V2

import Language.Python.Version3 as V3

import System.Exit

import System.Environment

data PythonVersion = Two | Three | Both

deriving (Eq, Show)

data Comparison = ParseFailed String | Equal | NotEqual String String

type Parser = String -> String -> Either ParseError (ModuleSpan, [Token])

main :: IO ()

main = do

args <- getArgs

case args of

(versionStr:inFile:_rest) ->

case parseVersion versionStr of

Nothing -> do

putStrLn $ "Unknown Python version: " ++ versionStr

exitFailure

Just version -> do

contents <- readFile inFile

let parsers = pickParsers version

comparisons = [parseAndCompare p inFile contents | p <- parsers]

test <- check comparisons

if test then exitWith ExitSuccess else exitSuccess

_other -> putStrLn "Incorrect command line. Expected: <2|3|n> inputFileName"

check :: [Comparison] -> IO Bool

check [] = return True -- must have all been equal

check (Equal:rest) = check rest

check (NotEqual s1 s2:_rest) = do

doubleLine

putStrLn "Round trip parse failed"

doubleLine

putStrLn "pretty1"

line

putStrLn s1

doubleLine

putStrLn "pretty2"

line

putStrLn s2

return False

check (ParseFailed e:_rest) = do

putStrLn "Parse failed with error: "

putStrLn e

return False

pickParsers :: PythonVersion -> [Parser]

pickParsers Two = [V2.parseModule]

pickParsers Three = [V3.parseModule]

pickParsers Both = [V2.parseModule, V3.parseModule]

parseAndCompare :: Parser -> FilePath -> String -> Comparison

parseAndCompare parser inFile contents =

case parseAndPretty parser inFile contents of

Left e -> ParseFailed $ prettyText e

Right pretty1 ->

case parseAndPretty parser "<pretty printed>" pretty1 of

Left e -> ParseFailed $ prettyText e

Right pretty2

| pretty1 == pretty2 -> Equal

| otherwise -> NotEqual pretty1 pretty2

line, doubleLine :: IO ()

line = putStrLn $ replicate 80 '-'

doubleLine = putStrLn $ replicate 80 '='

parseAndPretty :: Parser -> FilePath -> String -> Either ParseError String

parseAndPretty parser fileName contents =

case parser contents fileName of

Left e -> Left e

Right (ast, _comments) -> Right (prettyText ast ++ "\n")

parseVersion :: String -> Maybe PythonVersion

parseVersion "2" = Just Two

parseVersion "3" = Just Three

parseVersion "n" = Just Both

parseVersion _other = Nothing