<br><div class="gmail_quote">On Sat, Apr 2, 2011 at 7:45 AM, S. Doaitse Swierstra <span dir="ltr"><<a href="mailto:doaitse@swierstra.net">doaitse@swierstra.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div style="word-wrap: break-word;">Can you explain what are the advantages of your library over the online version of all applicative parsers in the uu-parsinglib, which are not restricted to the monoidal results?</div></blockquote>
<div><br><br> To tell you the truth, even though I've read the uu-parsinglib documentation I wasn't even aware of different parser types it allowed. The library documentation does not exactly advertise online parsers. I'm reading the "A Short Tutorial" paper now (<a href="http://www.cs.uu.nl/research/techreps/repo/CS-2008/2008-044.pdf">http://www.cs.uu.nl/research/techreps/repo/CS-2008/2008-044.pdf</a>). It is interesting, but very much misnamed: it is neither short nor a tutorial. It does a good job of explaining the library implementation, but there's very little in the way of usage. The Demo.Examples module on the other hand does not provide any example of incremental parsing.<br>
<br> Would you mind providing a short example of use of an uu-parsinglib online parser that actually takes advantage of incremental parsing? Here is such an example of incremental-parser use that you can adapt:<br><br>
<blockquote style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;" class="gmail_quote">{-# LANGUAGE OverloadedStrings #-}<br><br>module Main where<br><br>import Prelude hiding (null)<br>
import Data.ByteString.Char8 (ByteString, hGet, null, unpack)<br>import System.Environment (getArgs)<br>import System.IO (hIsEOF, IOMode(ReadMode), withFile)<br>import Text.ParserCombinators.Incremental<br><br>main= getArgs >>= mapM_ incremental<br>
<br>incremental filename = withFile filename ReadMode (flip processHandle testParser)<br> where processHandle h p = do chunk <- hGet h 1024<br> if null chunk <br> then putStrLn "EOF" >> extract (feedEof p)<br>
else extract (feed chunk p) >>= processHandle h<br> extract p = let (r, p') = resultPrefix p<br> in print r >> return p'<br><br>testParser :: Parser ByteString [Int]<br>
testParser = many0 (fmap (\digits-> [read $ unpack digits]) (takeWhile1 (\c-> c >= "0" && c <= "9"))<br> <<|> skip anyToken)<br></blockquote><br><br> This simple example will read a text file containing integers, in kilobyte chunks, and print out the list of integers. The parser is simplistic, but it serves to illustrate the main points of the interface:<br>
- the parser is fed input in chunks,<br> - the parsed results are read in chunks, and<br> - the input chunks may overlap with result components.<br>
</div></div><br>