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{-# LANGUAGE DeriveDataTypeable #-}
import PGF (PGF)
import qualified PGF
import Cache
import FastCGIUtils
import URLEncoding
import Network.FastCGI
import Text.JSON
import qualified Codec.Binary.UTF8.String as UTF8 (encodeString, decodeString)
import Control.Concurrent
import Control.Monad
import Data.Char
import qualified Data.Map as Map
import Data.Maybe
main :: IO ()
main = do initFastCGI
cache <- newCache PGF.readPGF
runFastCGIConcurrent' forkIO 100 (handleErrors (handleCGIErrors (cgiMain cache)))
cgiMain :: Cache PGF -> CGI CGIResult
cgiMain cache =
do path <- pathInfo
case filter (not . null) $ splitBy (=='/') path of
[file,command] -> do pgf <- liftIO $ readCache cache file
json <- pgfMain pgf command
outputJSONP json
_ -> throwCGIError 400 "Unknown resource" ["Unknown resource: " ++ show path,
"Use /grammar.pgf/command"]
pgfMain :: PGF -> String -> CGI JSValue
pgfMain pgf command =
case command of
"parse" -> return (doParse pgf) `ap` getText `ap` getCat `ap` getFrom
"complete" -> return (doComplete pgf) `ap` getText `ap` getCat `ap` getFrom `ap` getLimit
"linearize" -> return (doLinearize pgf) `ap` getTree `ap` getTo
"translate" -> return (doTranslate pgf) `ap` getText `ap` getCat `ap` getFrom `ap` getTo
"grammar" -> return (doGrammar pgf) `ap` requestAcceptLanguage
_ -> throwCGIError 400 "Unknown command" ["Unknown command: " ++ show command]
where
getText :: CGI String
getText = liftM (maybe "" (urlDecodeUnicode . UTF8.decodeString)) $ getInput "input"
getTree :: CGI PGF.Tree
getTree = do mt <- getInput "tree"
t <- maybe (throwCGIError 400 "No tree given" ["No tree given"]) return mt
maybe (throwCGIError 400 "Bad tree" ["Bad tree: " ++ t]) return (PGF.readTree t)
getCat :: CGI (Maybe PGF.Type)
getCat =
do mcat <- getInput "cat"
case mcat of
Nothing -> return Nothing
Just "" -> return Nothing
Just cat -> case PGF.readType cat of
Nothing -> throwCGIError 400 "Bad category" ["Bad category: " ++ cat]
Just typ | typ `elem` PGF.categories pgf -> return $ Just typ
| otherwise -> throwCGIError 400 "Unknown category" ["Unknown category: " ++ show typ]
getFrom :: CGI (Maybe PGF.Language)
getFrom = getLang "from"
getTo :: CGI (Maybe PGF.Language)
getTo = getLang "to"
getLimit :: CGI (Maybe Int)
getLimit = readInput "limit"
getLang :: String -> CGI (Maybe PGF.Language)
getLang i =
do mlang <- getInput i
case mlang of
Nothing -> return Nothing
Just "" -> return Nothing
Just l -> case PGF.readLanguage l of
Nothing -> throwCGIError 400 "Bad language" ["Bad language: " ++ l]
Just lang | lang `elem` PGF.languages pgf -> return $ Just lang
| otherwise -> throwCGIError 400 "Unknown language" ["Unknown language: " ++ l]
doTranslate :: PGF -> String -> Maybe PGF.Type -> Maybe PGF.Language -> Maybe PGF.Language -> JSValue
doTranslate pgf input mcat mfrom mto = showJSON $ map toJSObject
[[("from", PGF.showLanguage from),("to", PGF.showLanguage to),("text",output)]
| (from,trees) <- parse' pgf input mcat mfrom,
tree <- trees,
(to,output) <- linearize' pgf mto tree]
doParse :: PGF -> String -> Maybe PGF.Type -> Maybe PGF.Language -> JSValue
doParse pgf input mcat mfrom = showJSON $ map toJSObject
[[("from", PGF.showLanguage from),("tree",PGF.showTree tree)]
| (from,trees) <- parse' pgf input mcat mfrom,
tree <- trees ]
doComplete :: PGF -> String -> Maybe PGF.Type -> Maybe PGF.Language -> Maybe Int -> JSValue
doComplete pgf input mcat mfrom mlimit = showJSON $ map toJSObject $ limit
[[("from", PGF.showLanguage from),("text",text)]
| (from,compls) <- complete' pgf input mcat mfrom,
text <- compls]
where
limit xs = maybe xs (\n -> take n xs) mlimit
doLinearize :: PGF -> PGF.Tree -> Maybe PGF.Language -> JSValue
doLinearize pgf tree mto = showJSON $ map toJSObject
[[("to", PGF.showLanguage to),("text",text)] | (to,text) <- linearize' pgf mto tree]
doGrammar :: PGF -> Maybe (Accept Language) -> JSValue
doGrammar pgf macc = showJSON $ toJSObject
[("name", showJSON (PGF.abstractName pgf)),
("userLanguage", showJSON (selectLanguage pgf macc)),
("categories", showJSON categories),
("languages", showJSON languages)]
where languages = map toJSObject
[[("name", showJSON l),
("languageCode", showJSON $ fromMaybe "" (PGF.languageCode pgf l)),
("canParse", showJSON $ PGF.canParse pgf l)]
| l <- PGF.languages pgf]
categories = map toJSObject [[("cat", PGF.showType cat)] | cat <- PGF.categories pgf]
instance JSON PGF.CId where
readJSON x = readJSON x >>= maybe (fail "Bad language.") return . PGF.readLanguage
showJSON = showJSON . PGF.showLanguage
-- * PGF utilities
parse' :: PGF -> String -> Maybe PGF.Type -> Maybe PGF.Language -> [(PGF.Language,[PGF.Tree])]
parse' pgf input mcat mfrom =
[(from,ts) | from <- froms, PGF.canParse pgf from, let ts = PGF.parse pgf from cat input, not (null ts)]
where froms = maybe (PGF.languages pgf) (:[]) mfrom
cat = fromMaybe (PGF.startCat pgf) mcat
complete' :: PGF -> String -> Maybe PGF.Type -> Maybe PGF.Language -> [(PGF.Language,[String])]
complete' pgf input mcat mfrom =
[(from,ss) | from <- froms, PGF.canParse pgf from, let ss = PGF.complete pgf from cat input, not (null ss)]
where froms = maybe (PGF.languages pgf) (:[]) mfrom
cat = fromMaybe (PGF.startCat pgf) mcat
linearize' :: PGF -> Maybe PGF.Language -> PGF.Tree -> [(PGF.Language,String)]
linearize' pgf mto tree =
case mto of
Nothing -> PGF.linearizeAllLang pgf tree
Just to -> [(to,PGF.linearize pgf to tree)]
selectLanguage :: PGF -> Maybe (Accept Language) -> PGF.Language
selectLanguage pgf macc = case acceptable of
[] -> case PGF.languages pgf of
[] -> error "No concrete syntaxes in PGF grammar."
l:_ -> l
Language c:_ -> fromJust (langCodeLanguage pgf c)
where langCodes = mapMaybe (PGF.languageCode pgf) (PGF.languages pgf)
acceptable = negotiate (map Language langCodes) macc
langCodeLanguage :: PGF -> String -> Maybe PGF.Language
langCodeLanguage pgf code = listToMaybe [l | l <- PGF.languages pgf, PGF.languageCode pgf l == Just code]
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