{-# OPTIONS_GHC -fglasgow-exts -cpp #-}
{-|
Interactive shell.
> There is an inn, a merry old inn,
> beneath an old grey hill,
> And there they brew a beer so brown
> That the Man in the Moon himself came down
> one night to drink his fill...
-}
module Pugs.Shell where
import Pugs.Internals
#ifdef PUGS_HAVE_READLINE
import qualified System.Console.Readline as Readline
#endif
data Command
= CmdLoad FilePath
| CmdQuit
| CmdParse String
| CmdParseRaw String
| CmdRun RunOptions String
| CmdHelp
| CmdReset
data RunOptions = RunOpts { runOptDebug :: Bool
, runOptSeparately :: Bool
, runOptShowPretty :: Bool}
-- | read some input from the user
-- parse the input and return the corresponding command
getCommand :: IO Command
getCommand = do
input <- readline "pugs> "
doCommand input
doCommand :: Maybe String -> IO Command
doCommand Nothing = return CmdQuit
doCommand (Just line)
| all isSpace line = getCommand
| (s, _) <- break (== '#') line
, all isSpace s = getCommand
| otherwise = do
addHistory line
return $ parseCommandLine line
parseCommandLine :: String -> Command
parseCommandLine (':':'e':str) = CmdRun (RunOpts False True False) str
parseCommandLine (':':'E':str) = CmdRun (RunOpts True True False) str
parseCommandLine (':':'d':str) = CmdParse str
parseCommandLine (':':'D':str) = CmdParseRaw str
parseCommandLine (':':'q':_) = CmdQuit
parseCommandLine (':':'h':_) = CmdHelp
parseCommandLine (':':'r':_) = CmdReset
parseCommandLine (':':'l':str) = CmdLoad $ unwords (words str)
parseCommandLine str = CmdRun (RunOpts False False True) str
initializeShell :: IO ()
initializeShell
#ifdef PUGS_HAVE_READLINE
= Readline.initialize
#else
= return ()
#endif
readline :: String -> IO (Maybe String)
readline prompt
#ifdef PUGS_HAVE_READLINE
= Readline.readline prompt
#else
= do putStr prompt
input <- getLine
return $ Just input
#endif
addHistory :: String -> IO ()
#ifdef PUGS_HAVE_READLINE
addHistory str = Readline.addHistory str
#else
addHistory _ = return ()
#endif