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-----------------------------------------------------------------------------
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-- This is an abstract command-line parser used by both StaticFlags and
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-- (c) The University of Glasgow 2005
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-----------------------------------------------------------------------------
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module CmdLineParser (
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processArgs, OptKind(..),
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CmdLineP(..), getCmdLineState, putCmdLineState,
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EwM, addErr, addWarn, getArg, liftEwM, deprecate
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#include "HsVersions.h"
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--------------------------------------------------------
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-- The Flag and OptKind types
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--------------------------------------------------------
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{ flagName :: String, -- Flag, without the leading "-"
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flagOptKind :: OptKind m -- What to do if we see it
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-------------------------------
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data OptKind m -- Suppose the flag is -f
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= NoArg (EwM m ()) -- -f all by itself
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| HasArg (String -> EwM m ()) -- -farg or -f arg
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| SepArg (String -> EwM m ()) -- -f arg
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| Prefix (String -> EwM m ()) -- -farg
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| OptPrefix (String -> EwM m ()) -- -f or -farg (i.e. the arg is optional)
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| OptIntSuffix (Maybe Int -> EwM m ()) -- -f or -f=n; pass n to fn
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| IntSuffix (Int -> EwM m ()) -- -f or -f=n; pass n to fn
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| PassFlag (String -> EwM m ()) -- -f; pass "-f" fn
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| AnySuffix (String -> EwM m ()) -- -f or -farg; pass entire "-farg" to fn
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| PrefixPred (String -> Bool) (String -> EwM m ())
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| AnySuffixPred (String -> Bool) (String -> EwM m ())
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--------------------------------------------------------
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--------------------------------------------------------
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type Err = Located String
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type Warn = Located String
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-- EwM (short for "errors and warnings monad") is a
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-- monad transformer for m that adds an (err, warn) state
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newtype EwM m a = EwM { unEwM :: Located String -- Current arg
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-> m (Errs, Warns, a) }
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instance Monad m => Monad (EwM m) where
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(EwM f) >>= k = EwM (\l e w -> do { (e', w', r) <- f l e w
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; unEwM (k r) l e' w' })
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return v = EwM (\_ e w -> return (e, w, v))
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setArg :: Located String -> EwM m a -> EwM m a
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setArg l (EwM f) = EwM (\_ es ws -> f l es ws)
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addErr :: Monad m => String -> EwM m ()
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addErr e = EwM (\(L loc _) es ws -> return (es `snocBag` L loc e, ws, ()))
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addWarn :: Monad m => String -> EwM m ()
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addWarn msg = EwM (\(L loc _) es ws -> return (es, ws `snocBag` L loc w, ()))
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w = "Warning: " ++ msg
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deprecate :: Monad m => String -> EwM m ()
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; addWarn (arg ++ " is deprecated: " ++ s) }
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getArg :: Monad m => EwM m String
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getArg = EwM (\(L _ arg) es ws -> return (es, ws, arg))
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liftEwM :: Monad m => m a -> EwM m a
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liftEwM action = EwM (\_ es ws -> do { r <- action; return (es, ws, r) })
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-- -----------------------------------------------------------------------------
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-- A state monad for use in the command-line parser
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-- (CmdLineP s) typically instantiates the 'm' in (EwM m) and (OptKind m)
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newtype CmdLineP s a = CmdLineP { runCmdLine :: s -> (a, s) }
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instance Monad (CmdLineP s) where
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return a = CmdLineP $ \s -> (a, s)
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m >>= k = CmdLineP $ \s -> let
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(a, s') = runCmdLine m s
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in runCmdLine (k a) s'
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getCmdLineState :: CmdLineP s s
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getCmdLineState = CmdLineP $ \s -> (s,s)
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putCmdLineState :: s -> CmdLineP s ()
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putCmdLineState s = CmdLineP $ \_ -> ((),s)
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--------------------------------------------------------
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-- Processing arguments
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--------------------------------------------------------
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processArgs :: Monad m
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=> [Flag m] -- cmdline parser spec
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-> [Located String] -- args
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[Located String], -- spare args
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[Located String], -- errors
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[Located String] -- warnings
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processArgs spec args
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= do { (errs, warns, spare) <- unEwM (process args [])
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(panic "processArgs: no arg yet")
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; return (spare, bagToList errs, bagToList warns) }
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-- process :: [Located String] -> [Located String] -> EwM m [Located String]
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process [] spare = return (reverse spare)
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process (locArg@(L _ ('-' : arg)) : args) spare =
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case findArg spec arg of
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Just (rest, opt_kind) ->
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case processOneArg opt_kind rest arg args of
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Left err -> do { setArg locArg $ addErr err
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; process args spare }
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Right (action,rest) -> do { setArg locArg $ action
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; process rest spare }
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Nothing -> process args (locArg : spare)
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process (arg : args) spare = process args (arg : spare)
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processOneArg :: OptKind m -> String -> String -> [Located String]
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-> Either String (EwM m (), [Located String])
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processOneArg opt_kind rest arg args
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= let dash_arg = '-' : arg
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rest_no_eq = dropEq rest
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NoArg a -> ASSERT(null rest) Right (a, args)
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HasArg f | notNull rest_no_eq -> Right (f rest_no_eq, args)
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| otherwise -> case args of
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[] -> missingArgErr dash_arg
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(L _ arg1:args1) -> Right (f arg1, args1)
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SepArg f -> case args of
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[] -> unknownFlagErr dash_arg
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(L _ arg1:args1) -> Right (f arg1, args1)
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Prefix f | notNull rest_no_eq -> Right (f rest_no_eq, args)
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| otherwise -> unknownFlagErr dash_arg
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PrefixPred _ f | notNull rest_no_eq -> Right (f rest_no_eq, args)
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| otherwise -> unknownFlagErr dash_arg
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PassFlag f | notNull rest -> unknownFlagErr dash_arg
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| otherwise -> Right (f dash_arg, args)
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OptIntSuffix f | null rest -> Right (f Nothing, args)
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| Just n <- parseInt rest_no_eq -> Right (f (Just n), args)
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| otherwise -> Left ("malformed integer argument in " ++ dash_arg)
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IntSuffix f | Just n <- parseInt rest_no_eq -> Right (f n, args)
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| otherwise -> Left ("malformed integer argument in " ++ dash_arg)
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OptPrefix f -> Right (f rest_no_eq, args)
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AnySuffix f -> Right (f dash_arg, args)
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AnySuffixPred _ f -> Right (f dash_arg, args)
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findArg :: [Flag m] -> String -> Maybe (String, OptKind m)
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= case [ (removeSpaces rest, optKind)
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let optKind = flagOptKind flag,
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Just rest <- [stripPrefix (flagName flag) arg],
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arg_ok optKind rest arg ]
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arg_ok :: OptKind t -> [Char] -> String -> Bool
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arg_ok (NoArg _) rest _ = null rest
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arg_ok (HasArg _) _ _ = True
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arg_ok (SepArg _) rest _ = null rest
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arg_ok (Prefix _) rest _ = notNull rest
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arg_ok (PrefixPred p _) rest _ = notNull rest && p (dropEq rest)
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arg_ok (OptIntSuffix _) _ _ = True
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arg_ok (IntSuffix _) _ _ = True
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arg_ok (OptPrefix _) _ _ = True
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arg_ok (PassFlag _) rest _ = null rest
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arg_ok (AnySuffix _) _ _ = True
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arg_ok (AnySuffixPred p _) _ arg = p arg
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parseInt :: String -> Maybe Int
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-- Looks for "433" or "=342", with no trailing gubbins
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-- gibberish => Nothing
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parseInt s = case reads s of
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dropEq :: String -> String
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-- Discards a leading equals sign
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unknownFlagErr :: String -> Either String a
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unknownFlagErr f = Left ("unrecognised flag: " ++ f)
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missingArgErr :: String -> Either String a
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missingArgErr f = Left ("missing argument for flag: " ++ f)
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-- ---------------------------------------------------------------------
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errorsToGhcException :: [Located String] -> GhcException
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errorsToGhcException errs =
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let errors = vcat [ ppr l <> text ": " <> text e | L l e <- errs ]
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in UsageError (showSDoc $ withPprStyle cmdlineParserStyle errors)