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|
-- ------------------------------------------------------------
{- |
Module : HXPath
Copyright : Copyright (C) 2005 Torbel Kuseler, Uwe Schmidt
License : MIT
Maintainer : Uwe Schmidt
Maintainer : uwe@fh-wedel.de
Stability : experimental
Portability: portable
HXPath - XPath Evaluator of the Haskell XML Toolbox (Arrow version)
-}
-- ------------------------------------------------------------
module Main
where
import Text.XML.HXT.Arrow.XmlState.TypeDefs
import Text.XML.HXT.Core
import Text.XML.HXT.Curl
import Text.XML.HXT.XPath
import System.Console.GetOpt
import System.Environment
import System.Exit
import System.IO
-- ------------------------------------------------------------
-- |
-- the main program
main :: IO ()
main
= do
argv <- getArgs -- get the commandline arguments
(al, expr, src) <- cmdlineOpts argv -- and evaluate them, return a key-value list
[rc] <- runX (xpath al expr src) -- run the parser arrow
exitProg (rc >= c_err) -- set return code and terminate
-- ------------------------------------------------------------
exitProg :: Bool -> IO a
exitProg True = exitWith (ExitFailure 1)
exitProg False = exitWith ExitSuccess
-- ------------------------------------------------------------
-- |
-- the /real/ main program
--
-- runs in the trivial XmlState monad (with user state set to ())
-- so IO and access to global options is possible
xpath :: SysConfigList -> String -> String -> IOSArrow b Int
xpath cf expr src
= configSysVars cf -- set all global config options, the output file and the
>>> -- other user options are stored as key-value pairs in the stystem state
readDocument [withCurl []] src
>>>
evalXPathExpr
>>>
traceMsg 1 "evaluation finished"
>>>
traceSource
>>>
traceTree
>>>
( formatXPathResult $< getSysVar theIndent )
>>>
writeDocument [] "-"
>>>
getErrStatus
where
evalXPathExpr :: IOSArrow XmlTree XmlTree
evalXPathExpr
= traceMsg 1 ("evaluating XPath expression: " ++ expr)
>>>
replaceChildren ( getXPathTreesInDoc expr
>>>
filterErrorMsg
)
formatXPathResult :: Bool -> IOSArrow XmlTree XmlTree
formatXPathResult indent
= replaceChildren ( mkelem "xpath-result"
[ sattr "expr" expr, sattr "source" src ]
[ newline, getChildren >>> (this <+> newline) ]
)
where
newline
| indent = txt "\n"
| otherwise = none
-- ------------------------------------------------------------
--
-- the options definition part
-- see doc for System.Console.GetOpt
progName :: String
progName = "HXPath"
options :: [OptDescr SysConfig]
options
= generalOptions
++
inputOptions
++
outputOptions
usage :: [String] -> IO a
usage errl
| null errl
= do
hPutStrLn stdout use
exitProg False
| otherwise
= do
hPutStrLn stderr (concat errl ++ "\n" ++ use)
exitProg True
where
header = "HXPath - XPath Evaluator of the Haskell XML Toolbox (Arrow Version)\n" ++
"Usage: " ++ progName ++ " [OPTION...] <XPath expr> <URL or FILE>"
use = usageInfo header options
cmdlineOpts :: [String] -> IO ([SysConfig], String, String)
cmdlineOpts argv
= case (getOpt Permute options argv) of
(scfg,n,[] )
-> do
(ex, sa) <- src n
help (getConfigAttr a_help scfg)
return (scfg, ex, sa)
(_,_,errs)
-> usage errs
where
src [expr, url]
= return (expr, url)
src []
= usage ["XPath expression and input file/url missing"]
src [_]
= usage ["input file/url missing"]
src _
= usage ["too many arguments"]
help "1" = usage []
help _ = return ()
-- ------------------------------------------------------------
|
