joehl@web.de
2000-Dec-20 12:56 UTC
[Rd] Inconsistency in creating/opening/closing/destroying connections (PR#787)
I expected close() to be the opposite of open(), but> # create a connection > con <- file("ex.data") > # open it > open(con, "w") > # close it > close(con) > # re-open it > open(con, "w")Error in open.connection(con, "w") : invalid connection> > conError in summary.connection(x) : invalid connection> # is obviously pointing to a non-existing connectionhelp to showConnections obviously also was assuming that there may EXIST something like a CLOSED connection, as it says all logical: if true all connections, including CLOSED ONES and the standard ones are displayed. If false only open user-created connections are included. So this is at least a documentation bug, but what about having something like CreateConnection OpenConnection CloseConnection DestroyConnection Is there any reason to have (as currently) OpenConnection seperated from CreateConnection but CloseConnection and DestroyConnection combined? Regards Jens Oehlschlägel --please do not edit the information below-- Version: platform = i386-pc-mingw32 arch = x86 os = Win32 system = x86, Win32 status = major = 1 minor = 2.0 year = 2000 month = 12 day = 15 language = R Windows NT 4.0 (build 1381) Service Pack 6 Search Path: .GlobalEnv, package:ctest, Autoloads, package:base _______________________________________________________________________________ Alles unter einem Dach: Informationen, Fun, E-Mails. Bei WEB.DE: http://web.de Die große Welt der Kommunikation: E-Mail, Fax, SMS, WAP: http://freemail.web.de -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Prof Brian D Ripley
2000-Dec-20 13:14 UTC
[Rd] Inconsistency in creating/opening/closing/destroying connections (PR#787)
On Wed, 20 Dec 2000 joehl@web.de wrote:> I expected close() to be the opposite of open(), butWhy? It is not documented to be so, as far as I know.> > # create a connection > > con <- file("ex.data") > > # open it > > open(con, "w") > > # close it > > close(con) > > # re-open it > > open(con, "w") > Error in open.connection(con, "w") : invalid connection > > > > con > Error in summary.connection(x) : invalid connection > > # is obviously pointing to a non-existing connection > > help to showConnections obviously also was assuming that there may EXIST something like a CLOSED connection, as it says > all logical: if true all connections, including CLOSED ONES and the standard ones are displayed. If false only open user-created connections are included. > > So this is at least a documentation bug, but what about having something likeCan you please elucidate here? I don't think any documentation says open is the opposite of close. I think you are just assuming things that are not said. Note: ?close says `close' closes and destroys a connection. not just closes it, so there can be closed and not destroyed connections.> CreateConnection > OpenConnection > CloseConnection > DestroyConnection > > Is there any reason to have (as currently) OpenConnection seperated from CreateConnection but CloseConnection and DestroyConnection combined?Yes. These are S4-type connections, and that is what S4 does. -- Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._