module FST.GetOpt (
ArgOrder(..), OptDescr(..), ArgDescr(..), usageInfo, getOpt
) where
import Data.List (isPrefixOf)
data ArgOrder a
= RequireOrder
| Permute
| ReturnInOrder (String -> a)
data OptDescr a =
Option [Char]
[String]
(ArgDescr a)
String
data ArgDescr a
= NoArg a
| ReqArg (String -> a) String
| OptArg (Maybe String -> a) String
data OptKind a
= Opt a
| NonOpt String
| EndOfOpts
| OptErr String
usageInfo :: String
-> [OptDescr a]
-> String
usageInfo header optDescr = unlines (header:table)
where (ss,ls,ds) = (unzip3 . map fmtOpt) optDescr
table = zipWith3 paste (sameLen ss) (sameLen ls) (sameLen ds)
paste x y z = " " ++ x ++ " " ++ y ++ " " ++ z
sameLen xs = flushLeft ((maximum . map length) xs) xs
flushLeft n xs = [ take n (x ++ repeat ' ') | x <- xs ]
fmtOpt :: OptDescr a -> (String,String,String)
fmtOpt (Option sos los ad descr) = (sepBy ", " (map (fmtShort ad) sos),
sepBy ", " (map (fmtLong ad) los),
descr)
where sepBy _ [] = ""
sepBy _ [x] = x
sepBy sep (x:xs) = x ++ sep ++ sepBy sep xs
fmtShort :: ArgDescr a -> Char -> String
fmtShort (NoArg _ ) so = "-" ++ [so]
fmtShort (ReqArg _ ad) so = "-" ++ [so] ++ " " ++ ad
fmtShort (OptArg _ ad) so = "-" ++ [so] ++ "[" ++ ad ++ "]"
fmtLong :: ArgDescr a -> String -> String
fmtLong (NoArg _ ) lo = "--" ++ lo
fmtLong (ReqArg _ ad) lo = "--" ++ lo ++ "=" ++ ad
fmtLong (OptArg _ ad) lo = "--" ++ lo ++ "[=" ++ ad ++ "]"
getOpt :: ArgOrder a
-> [OptDescr a]
-> [String]
-> ([a],[String],[String])
getOpt _ _ [] = ([],[],[])
getOpt ordering optDescr args = procNextOpt opt ordering
where procNextOpt (Opt o) _ = (o:os,xs,es)
procNextOpt (NonOpt x) RequireOrder = ([],x:rest,[])
procNextOpt (NonOpt x) Permute = (os,x:xs,es)
procNextOpt (NonOpt x) (ReturnInOrder f) = (f x :os, xs,es)
procNextOpt EndOfOpts RequireOrder = ([],rest,[])
procNextOpt EndOfOpts Permute = ([],rest,[])
procNextOpt EndOfOpts (ReturnInOrder f) = (map f rest,[],[])
procNextOpt (OptErr e) _ = (os,xs,e:es)
(opt,rest) = getNext args optDescr
(os,xs,es) = getOpt ordering optDescr rest
getNext :: [String] -> [OptDescr a] -> (OptKind a,[String])
getNext (('-':'-':[]):rest) _ = (EndOfOpts,rest)
getNext (('-':'-':xs):rest) optDescr = longOpt xs rest optDescr
getNext (('-':x:xs) :rest) optDescr = shortOpt x xs rest optDescr
getNext (a :rest) _ = (NonOpt a,rest)
getNext [] _ = error "getNext: impossible"
longOpt :: String -> [String] -> [OptDescr a] -> (OptKind a,[String])
longOpt xs rest optDescr = long ads arg rest
where (opt,arg) = break (=='=') xs
options = [ o | o@(Option _ ls _ _) <- optDescr, l <- ls, opt `isPrefixOf` l ]
ads = [ ad | Option _ _ ad _ <- options ]
optStr = ("--"++opt)
long (_:_:_) _ rest1 = (errAmbig options optStr,rest1)
long [NoArg a ] [] rest1 = (Opt a,rest1)
long [NoArg _ ] ('=':_) rest1 = (errNoArg optStr,rest1)
long [ReqArg _ d] [] [] = (errReq d optStr,[])
long [ReqArg f _] [] (r:rest1) = (Opt (f r),rest1)
long [ReqArg f _] ('=':ys) rest1 = (Opt (f ys),rest1)
long [OptArg f _] [] rest1 = (Opt (f Nothing),rest1)
long [OptArg f _] ('=':ys) rest1 = (Opt (f (Just ys)),rest1)
long [_] (_ :_) _ = error "long: impossible"
long [] _ rest1 = (errUnrec optStr,rest1)
shortOpt :: Char -> String -> [String] -> [OptDescr a] -> (OptKind a,[String])
shortOpt x xs rest optDescr = short ads xs rest
where options = [ o | o@(Option ss _ _ _) <- optDescr, s <- ss, x == s ]
ads = [ ad | Option _ _ ad _ <- options ]
optStr = '-':[x]
short (_:_:_) _ rest1 = (errAmbig options optStr,rest1)
short (NoArg a :_) [] rest1 = (Opt a,rest1)
short (NoArg a :_) ys rest1 = (Opt a,('-':ys):rest1)
short (ReqArg _ d:_) [] [] = (errReq d optStr,[])
short (ReqArg f _:_) [] (r:rest1) = (Opt (f r),rest1)
short (ReqArg f _:_) ys rest1 = (Opt (f ys),rest1)
short (OptArg f _:_) [] rest1 = (Opt (f Nothing),rest1)
short (OptArg f _:_) ys rest1 = (Opt (f (Just ys)),rest1)
short [] [] rest1 = (errUnrec optStr,rest1)
short [] ys rest1 = (errUnrec optStr,('-':ys):rest1)
errAmbig :: [OptDescr a] -> String -> OptKind a
errAmbig ods optStr = OptErr (usageInfo header ods)
where header = "option `" ++ optStr ++ "' is ambiguous; could be one of:"
errReq :: String -> String -> OptKind a
errReq d optStr = OptErr ("option `" ++ optStr ++ "' requires an argument " ++ d ++ "\n")
errUnrec :: String -> OptKind a
errUnrec optStr = OptErr ("unrecognized option `" ++ optStr ++ "'\n")
errNoArg :: String -> OptKind a
errNoArg optStr = OptErr ("option `" ++ optStr ++ "' doesn't allow an argument\n")