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|
{-
- This example is similar to the commandline iconv program.
- Author: Conrad Parker, July 2007
Usage: hiconv [options] filename
-h, -? --help, --usage Display this help and exit
-f encoding --from-code=encoding Convert characters from encoding
-t encoding --to-code=encoding Convert characters to encoding
-c --discard Discard invalid characters from output
--transliterate Transliterate unconvertable characters
-o file --output=file Specify output file (instead of stdout)
-}
module Main where
import Control.Monad (when)
import System.Environment (getArgs, getProgName)
import System.Console.GetOpt (getOpt, usageInfo,
OptDescr(..), ArgDescr(..), ArgOrder(..))
import System.Exit (exitFailure)
import qualified Data.ByteString.Lazy as Lazy
import qualified Codec.Text.IConv as IConv
------------------------------------------------------------
-- main
--
main :: IO ()
main = do
args <- getArgs
(config, filenames) <- processArgs args
let inputFile = head filenames
input <- case inputFile of
"-" -> Lazy.getContents
_ -> Lazy.readFile inputFile
let convert = case fuzzyConvert config of
Nothing -> IConv.convert
Just fuzz -> IConv.convertFuzzy fuzz
output = convert (fromEncoding config) (toEncoding config) input
o = outputFile config
case o of
"-" -> Lazy.putStr output
_ -> Lazy.writeFile o output
------------------------------------------------------------
-- Option handling
--
data Config =
Config {
fromEncoding :: String,
toEncoding :: String,
fuzzyConvert :: Maybe IConv.Fuzzy,
outputFile :: FilePath
}
defaultConfig =
Config {
fromEncoding = "",
toEncoding = "",
fuzzyConvert = Nothing,
outputFile = "-"
}
data Option = Help
| FromEncoding String
| ToEncoding String
| Discard | Translit
| OutputFile String
deriving Eq
options :: [OptDescr Option]
options = [ Option ['h', '?'] ["help", "usage"] (NoArg Help)
"Display this help and exit"
, Option ['f'] ["from-code"] (ReqArg FromEncoding "encoding")
"Convert characters from encoding"
, Option ['t'] ["to-code"] (ReqArg ToEncoding "encoding")
"Convert characters to encoding"
, Option ['c'] ["discard"] (NoArg Discard)
"Discard invalid characters from output"
, Option [] ["transliterate"] (NoArg Translit)
"Transliterate unconvertable characters"
, Option ['o'] ["output"] (ReqArg OutputFile "file")
"Specify output file (instead of stdout)"
]
processArgs :: [String] -> IO (Config, [String])
processArgs args = do
case getOpt Permute options args of
(opts, args, errs) -> do
processHelp opts
let config = processConfig defaultConfig opts
checkConfig errs config args
return (config, args)
checkConfig :: [String] -> Config -> [String] -> IO ()
checkConfig errs config filenames = do
when (any null [fromEncoding config, toEncoding config] || null filenames) $
processHelp [Help]
when (not (null errs)) $ do
mapM_ putStr errs
processHelp [Help]
processHelp :: [Option] -> IO ()
processHelp opts = do
name <- getProgName
let header = "\nUsage: " ++ name ++ " [options] filename\n"
when (Help `elem` opts) $ do
putStrLn $ usageInfo header options
exitFailure
processConfig :: Config -> [Option] -> Config
processConfig = foldl processOneOption
where
processOneOption config (FromEncoding f) =
config {fromEncoding = f}
processOneOption config (ToEncoding t) =
config {toEncoding = t}
processOneOption config (OutputFile o) =
config {outputFile = o}
processOneOption config Discard =
config {fuzzyConvert = Just IConv.Discard}
processOneOption config Translit =
config {fuzzyConvert = Just IConv.Transliterate}
|
