Re: [Haskell-cafe] Blocking IO FIFOs
Perhaps an interleaving solution as in process-conduit is still viable: - Check if one or both of the fifo's are still ready (Based on your statement about the reading end receiving EOF hIsEOF should work here). If both fifos are done the query is finished so break the loop. - Check if some output is available on oh. If so read some of it. Repeat. - Otherwise check if some output is available on eh. If so read some of it. Repeat loop I also see you don't do anything with the std_out and std_err pipes of bash as given by runInteractiveProcess. These could also cause a problem even when the FIFO's are working correctly. Replace these by handles to the null file or let the output be dumped on the parent's std_in and std_out (StdStream Inherit). On Sat, Oct 20, 2012 at 4:00 PM, Jason Dusek jason.du...@gmail.com wrote: For my application, it's important to be able to run multiple queries against the same Bash session. Waiting for Bash to shut down is thus not a viable way to finalize the response. Perhaps I can spawn two cats with their outputs connected to the FIFOs and wait for them to terminate. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Fwd: hdbc parametrized select
This was not sent to the cafe since I used the wrong from address. -- Forwarded message -- From: Asten, W.G.G. van (Wilfried, Student M-CSC) w.g.g.vanas...@student.utwente.nl Date: Thu, Oct 18, 2012 at 12:27 PM Subject: Re: [Haskell-cafe] hdbc parametrized select To: s9gf4...@gmail.com Cc: haskell-cafe@haskell.org To my knowledge you can combine execute and the fetch functions like this: find conn id = do stmt - prepare conn SELECT * FROM table WHERE id = ? LIMIT 1 excute stmt [id] row - fetchRow stmt On Thu, Oct 18, 2012 at 10:51 AM, s9gf4...@gmail.com wrote: does hdbc have parametrized selects ? There is execute execute :: Statement - [SqlValue] - IO Integer and some other functions which get list of parameters but return IO Integer or IO () and there is other couple of functions fetchRow :: Statement - IO (Maybe [SqlValue]) which return values of select but do not get parameters How can i execute parametrized select with hdbc ? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] HXT: how to get sibling element
I'm am not really familiar with XML parsing in Haskell, but I am
wondering why, if you have an xml file, you not simply name the
element after the type of contents:
book
titleSome Story/title
descriptionThis story about../description
authorTom Smith/author
/book
Alternatively you could use the class or some type attribute to
indicate the type.
Regards,
Wilfried van Asten
2012/3/15 Никитин Лев leon.v.niki...@pravmail.ru:
Hello, haskellers.
Suppose we have this xml doc (maybe, little stupid):
div
spanSome story/span
spanDescription/span: This story about...
spanAuthor/span: Tom Smith
/div
In the end I whant to get list: [(Title, Some story),
(Description,This story about...), (Author, Tom Smith)],
or, maybe this: Book Some story [(description,This story about...),
(Author, Tom Smith)] (Book = Book String [(String, String)].
First span is a special case then others and I undestand how to process it:
===
import Text.XML.HXT.Core
import Text.XML.HXT.Curl
import Text.XML.HXT.HTTP
pageURL = http://localhost/test.xml;
main = do
r - runX (configSysVars [withCanonicalize no, withValidate no, withTrace
0, withParseHTML no]
readDocument [withErrors no, withWarnings no, withHTTP []]
pageURL
getChildren isElem hasName div listA (getChildren
hasName span) getTitle + getSections)
putStrLn Статьи:
putStr
mapM_ putStr $ map (\i - (fst i) ++ : ++ (snd i) ++ | ) r
putStrLn
getTitle = arr head getChildren getText arr trim arr
(Title,)
getSections = arr tail unlistA ((getChildren getText arr
trim) (getChildren getText arr trim))
ltrim [] = []
ltrim (' ':x) = ltrim x
ltrim ('\n':x) = ltrim x
ltrim ('\r':x) = ltrim x
ltrim ('\t':x) = ltrim x
ltrim x = x
rtrim = reverse . ltrim . reverse
trim = ltrim . rtrim
===
And I' get list: [(Title, Some story), (Description,Description),
(Author, Author)]
(Maybe, there is a better way to get this list?)
But I cannot find a way to get text that followes some span.
I suppose that I have to use function from
Data.Tree.NavigatableTree.XPathAxis, but I don't puzzle out how to do it.
Please, help me.
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Re: [Haskell-cafe] HXT: how to get sibling element
ArrowNavigatableTree can also get a following sibling Axis: http://hackage.haskell.org/packages/archive/hxt/9.2.2/doc/html/Control-Arrow-ArrowNavigatableTree.html Wilfried 2012/3/15 Никитин Лев leon.v.niki...@pravmail.ru: Oh, yes! In this situation with so poor structured source I can try to use tagsoup. (or I'll take a look at xml-conduit). Nevertheless for better undestanding HXT it will be interesting to solve this problem in HXT. Or is it impossible? 15.03.2012, 20:08, Asten, W.G.G. van (Wilfried, Student B-TI) w.g.g.vanas...@student.utwente.nl: You might want to check out the xml-conduit package. It has preceding and following sibling Axis. I am not sure how the package works exactly, but it seems to be a good starting point. 2012/3/15 Никитин Лев leon.v.niki...@pravmail.ru: I absolutly agree with you but unfortunetly, it is not my xml file. It is extraction from html page of public web server. I cannot to change format of this html page. Sorry. I had to explain it in first letter. But than what about to get sibling text (geting sibling is an separate interesting tasks with no matter for my contrete case). ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
