1 -----------------------------------------------------------------------------
5 -- This is an abstract command-line parser used by both StaticFlags and
8 -- (c) The University of Glasgow 2005
10 -----------------------------------------------------------------------------
12 module CmdLineParser (
13 processArgs, OptKind(..),
14 CmdLineP(..), getCmdLineState, putCmdLineState
17 #include "HsVersions.h"
22 data OptKind m -- Suppose the flag is -f
23 = NoArg (m ()) -- -f all by itself
24 | HasArg (String -> m ()) -- -farg or -f arg
25 | SepArg (String -> m ()) -- -f arg
26 | Prefix (String -> m ()) -- -farg
27 | OptPrefix (String -> m ()) -- -f or -farg (i.e. the arg is optional)
28 | OptIntSuffix (Maybe Int -> m ()) -- -f or -f=n; pass n to fn
29 | IntSuffix (Int -> m ()) -- -f or -f=n; pass n to fn
30 | PassFlag (String -> m ()) -- -f; pass "-f" fn
31 | AnySuffix (String -> m ()) -- -f or -farg; pass entire "-farg" to fn
32 | PrefixPred (String -> Bool) (String -> m ())
33 | AnySuffixPred (String -> Bool) (String -> m ())
35 processArgs :: Monad m
36 => [(String, OptKind m)] -- cmdline parser spec
39 [String], -- spare args
42 processArgs spec args = process spec args [] []
44 process _spec [] spare errs =
45 return (reverse spare, reverse errs)
47 process spec (dash_arg@('-':arg):args) spare errs =
48 case findArg spec arg of
50 case processOneArg action rest arg args of
51 Left err -> process spec args spare (err:errs)
52 Right (action,rest) -> action >> process spec rest spare errs
53 Nothing -> process spec args (dash_arg:spare) errs
55 process spec (arg:args) spare errs =
56 process spec args (arg:spare) errs
59 processOneArg :: OptKind m -> String -> String -> [String]
60 -> Either String (m (), [String])
61 processOneArg action rest arg args
62 = let dash_arg = '-' : arg
63 rest_no_eq = dropEq rest
65 NoArg a -> ASSERT(null rest) Right (a, args)
67 HasArg f | notNull rest_no_eq -> Right (f rest_no_eq, args)
68 | otherwise -> case args of
69 [] -> missingArgErr dash_arg
70 (arg1:args1) -> Right (f arg1, args1)
72 SepArg f -> case args of
73 [] -> unknownFlagErr dash_arg
74 (arg1:args1) -> Right (f arg1, args1)
76 Prefix f | notNull rest_no_eq -> Right (f rest_no_eq, args)
77 | otherwise -> unknownFlagErr dash_arg
79 PrefixPred _ f | notNull rest_no_eq -> Right (f rest_no_eq, args)
80 | otherwise -> unknownFlagErr dash_arg
82 PassFlag f | notNull rest -> unknownFlagErr dash_arg
83 | otherwise -> Right (f dash_arg, args)
85 OptIntSuffix f | null rest -> Right (f Nothing, args)
86 | Just n <- parseInt rest_no_eq -> Right (f (Just n), args)
87 | otherwise -> Left ("malformed integer argument in " ++ dash_arg)
89 IntSuffix f | Just n <- parseInt rest_no_eq -> Right (f n, args)
90 | otherwise -> Left ("malformed integer argument in " ++ dash_arg)
92 OptPrefix f -> Right (f rest_no_eq, args)
93 AnySuffix f -> Right (f dash_arg, args)
94 AnySuffixPred _ f -> Right (f dash_arg, args)
97 findArg :: [(String,OptKind a)] -> String -> Maybe (String,OptKind a)
99 = case [ (removeSpaces rest, k)
101 Just rest <- [maybePrefixMatch pat arg],
107 arg_ok :: OptKind t -> [Char] -> String -> Bool
108 arg_ok (NoArg _) rest _ = null rest
109 arg_ok (HasArg _) _ _ = True
110 arg_ok (SepArg _) rest _ = null rest
111 arg_ok (Prefix _) rest _ = notNull rest
112 arg_ok (PrefixPred p _) rest _ = notNull rest && p (dropEq rest)
113 arg_ok (OptIntSuffix _) _ _ = True
114 arg_ok (IntSuffix _) _ _ = True
115 arg_ok (OptPrefix _) _ _ = True
116 arg_ok (PassFlag _) rest _ = null rest
117 arg_ok (AnySuffix _) _ _ = True
118 arg_ok (AnySuffixPred p _) _ arg = p arg
120 parseInt :: String -> Maybe Int
121 -- Looks for "433" or "=342", with no trailing gubbins
123 -- gibberish => Nothing
124 parseInt s = case reads s of
128 dropEq :: String -> String
129 -- Discards a leading equals sign
133 unknownFlagErr :: String -> Either String a
134 unknownFlagErr f = Left ("unrecognised flag: " ++ f)
136 missingArgErr :: String -> Either String a
137 missingArgErr f = Left ("missing argument for flag: " ++ f)
139 -- -----------------------------------------------------------------------------
140 -- A state monad for use in the command-line parser
142 newtype CmdLineP s a = CmdLineP { runCmdLine :: s -> (a, s) }
144 instance Monad (CmdLineP s) where
145 return a = CmdLineP $ \s -> (a, s)
146 m >>= k = CmdLineP $ \s -> let
147 (a, s') = runCmdLine m s
148 in runCmdLine (k a) s'
150 getCmdLineState :: CmdLineP s s
151 getCmdLineState = CmdLineP $ \s -> (s,s)
152 putCmdLineState :: s -> CmdLineP s ()
153 putCmdLineState s = CmdLineP $ \_ -> ((),s)