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|
{-# LANGUAGE DeriveDataTypeable #-}
import PGF (PGF)
import qualified PGF
import FastCGIUtils
import URLEncoding
import Network.CGI
import Text.JSON
import qualified Codec.Binary.UTF8.String as UTF8 (encodeString, decodeString)
import Control.Monad
import Data.Char
import qualified Data.Map as Map
import Data.Maybe
grammarFile :: FilePath
grammarFile = "grammar.pgf"
main :: IO ()
main = do initFastCGI
r <- newDataRef
loopFastCGI (handleErrors (handleCGIErrors (fcgiMain r)))
fcgiMain :: DataRef PGF -> CGI CGIResult
fcgiMain ref = getData (liftIO . PGF.readPGF) ref grammarFile >>= cgiMain
cgiMain :: PGF -> CGI CGIResult
cgiMain pgf =
do path <- pathInfo
json <- case path 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
"/info" -> return (doInfo pgf) `ap` requestAcceptLanguage
_ -> throwCGIError 404 "Not Found" ["Resource not found: " ++ path]
outputJSON json
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.Category)
getCat =
do mcat <- getInput "cat"
case mcat of
Just "" -> return Nothing
Just cat | cat `notElem` PGF.categories pgf ->
throwCGIError 400 "Unknown category" ["Unknown category: " ++ cat]
_ -> return mcat
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
Just "" -> return Nothing
Just lang | lang `notElem` PGF.languages pgf ->
throwCGIError 400 "Unknown language" ["Unknown language: " ++ lang]
_ -> return mlang
doTranslate :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> Maybe PGF.Language -> JSValue
doTranslate pgf input mcat mfrom mto = showJSON $ map toJSObject
[[("from",from),("to",to),("text",output)]
| (from,trees) <- parse' pgf input mcat mfrom,
tree <- trees,
(to,output) <- linearize' pgf mto tree]
doParse :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> JSValue
doParse pgf input mcat mfrom = showJSON $ map toJSObject
[[("from",from),("tree",PGF.showTree tree)]
| (from,trees) <- parse' pgf input mcat mfrom,
tree <- trees ]
doComplete :: PGF -> String -> Maybe PGF.Category -> Maybe PGF.Language -> Maybe Int -> JSValue
doComplete pgf input mcat mfrom mlimit = showJSON $ map toJSObject $ limit
[[("from",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",to),("text",text)] | (to,text) <- linearize' pgf mto tree]
doInfo :: PGF -> Maybe (Accept Language) -> JSValue
doInfo 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", cat)] | cat <- PGF.categories pgf]
-- * PGF utilities
parse' :: PGF -> String -> Maybe PGF.Category -> 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.Category -> Maybe PGF.Language -> [(PGF.Language,[String])]
complete' pgf input mcat mfrom =
[(from,ss) | from <- froms, PGF.canParse pgf from, let ss = complete pgf from cat input, not (null ss)]
where froms = maybe (PGF.languages pgf) (:[]) mfrom
cat = fromMaybe (PGF.startCat pgf) mcat
complete :: PGF -> PGF.Language -> PGF.Category -> String -> [String]
complete pgf from cat input =
let (ws,prefix) = tokensAndPrefix input
state0 = PGF.initState pgf from cat
state = foldl PGF.nextState state0 ws
compls = PGF.getCompletions state prefix
in [unwords (ws++[c]) ++ " " | c <- Map.keys compls]
tokensAndPrefix :: String -> ([String],String)
tokensAndPrefix s | not (null s) && isSpace (last s) = (words s, "")
| null ws = ([],"")
| otherwise = (init ws, last ws)
where ws = words s
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
[] -> "" -- FIXME: error?
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]
-- * General CGI and JSON stuff
outputJSON :: JSON a => a -> CGI CGIResult
outputJSON x = do setHeader "Content-Type" "text/json; charset=utf-8"
outputStrict $ UTF8.encodeString $ encode x
outputStrict :: String -> CGI CGIResult
outputStrict x | x == x = output x
| otherwise = fail "I am the pope."
|
