Xotcl June 2005

xotcl@alice.wu.ac.at

3 participants
4 discussions

Re: [Xotcl] xo beginner
by Kristoffer Lawson 25 Jun '05

25 Jun '05

On 25 Jun 2005, at 12:59, Mads Linden wrote: > Thanks > > I guess I just have to get my head around things like that, a bit > dangerous > I feel to call methods before contruct. > > It would be ok if it was "procs" that worked like that insode the > classs, > but not instprocs :( Well, you can ask the developers for the reason. I remember stumbling across it myself at one point. However, I also remember there was a fairly sensible reason for that. -dash calling is meant for initialisation so in a sense you can think of it as belonging to the init. It is, after all, the method used for initialising parameters. / http://www.fishpool.com/~setok/

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RE: [Xotcl] xo beginner
by Mads Linden 25 Jun '05

25 Jun '05

Thanks I guess I just have to get my head around things like that, a bit dangerous I feel to call methods before contruct. It would be ok if it was "procs" that worked like that insode the classs, but not instprocs :( Mads -----Original Message----- From: Kristoffer Lawson [mailto:setok@fishpool.com] Sent: 25 June 2005 11:49 To: Mads Linden Subject: Re: [Xotcl] xo beginner On 25 Jun 2005, at 04:08, Mads Linden wrote: > i am trying to learn XO....... so be nice :) > Hi, always nice to see that interest in XOTcl is growing (from a user's point of view). > ##### > > Class Project > > Project instproc init {} { > puts "INIT" > } > > Project instproc getarg {value} { > puts "getarg : $value" > } > > > Project .p -getarg 1 > > ##### > > Since xotcl allow method call in the same line as the creation of the > instance I offcourse tried that out == > > This gives me > > > >>> getarg : 1 >>> INIT >>> >>> > > I expected it to call the constructor (init) before method. > Actually the -dash methods are called first. There was actually a reason for this, but I cannot quite remember what it was. Something to do with wanting to initialise things before the actual init method. If you want to be sure to call init first do: Project .p -init -getarg 1 / http://www.fishpool.com/~setok/

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xo beginner
by Mads Linden 25 Jun '05

25 Jun '05

hi all i am trying to learn XO....... so be nice :) the question: ##### Class Project Project instproc init {} { puts "INIT" } Project instproc getarg {value} { puts "getarg : $value" } Project .p -getarg 1 ##### Since xotcl allow method call in the same line as the creation of the instance I offcourse tried that out == This gives me >> getarg : 1 >> INIT I expected it to call the constructor (init) before method. Regards Mads

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gdbm/sdbm/textfile database trouble
by Walter Augustin 16 Jun '05

16 Jun '05

Hi! I am quite new to [XO]Tcl and currently working on some scripts for Prof. Neumann's OO programming class. I run my scripts under Windows which has been working well so far - until I tried to run the "Cached WebPage" which depends upon one out of three offered storage resources. In the slides, Prof. Neumann offers to use TextFile, Gdbm and Sdbm: package require xotcl::store::textfile; set DBClass Storage=TextFile #package require xotcl::store::gdbm; set DBClass Storage=Gdbm #package require xotcl::store::sdbm; set DBClass Storage=Sdbm In the "Cache" class this should be used like this: Class Cache Cache instproc init {} { Storage=TextFile [self]::db ;# Erzeuge DB als Unterobjekt [self]::db open [self] ;# öffne DB mit aktuellen Namen des Objekts next } Now I tried all three possibilities, uncommenting lines and changing the "Storage=Textfile|Gdbm|Sdbm" part of the script. The results leave me in confusion, since the errors seem to be all different: [TextFile:] C:\Programme\tcl\scripts\stock>tclsh stock.xotcl couldn't open "::cache": no such file or directory while executing "::open $filename a+" (procedure "set" line 21) ::cache::db ::Storage=TextFile->set invoked from within "[self]::db set $url [list date $date content $page]" (procedure "store" line 4) ::cache ::Cache->store invoked from within "cache store $url $content" (procedure "loadPage" line 15) ::s1 ::CachedWebPage->loadPage invoked from within "my loadPage " (procedure "getContent" line 3) ::s1 ::WebPage->getContent invoked from within "my getContent" (procedure "getRate" line 4) ::s1 ::StockInfo->getRate invoked from within "s1 getRate" (file "stock.xotcl" line 116) [Gdbm:] C:\Programme\tcl\scripts\stock>tclsh stock.xotcl can't find package xotcl::store::gdbm while executing "package require xotcl::store::gdbm" (file "includes.inc" line 4) invoked from within "source includes.inc" (file "stock.xotcl" line 1) (-> Okay, the package is missing at all. I could make Stefan Vogel's Tcl wrapper port work - although the installation package was missing the pkgIndex.tcl file which he mailed me separately, but the XOTcl extension seems just not to be available under Windows. So, next I tried:) [Sdbm:] C:\Programme\tcl\scripts\stock>tclsh stock.xotcl Open on '::cache::db' failed with '::cache'. ::cache::db ::Storage=Sdbm->open invoked from within "[self]::db open [self] " (procedure "init" line 4) ::cache ::Cache->init ::Cache ::xotcl::Class->create ::Cache ::xotcl::Class->unknown invoked from within "Cache cache " (file "stock.xotcl" line 87) Source code is from Prof. Neumann: http://nm.wu-wien.ac.at/Lehre/oo2/stockinfo.xotcl I just commented out the package require Gdbm part and placed the three variants (see above) in the head of the script ("includes.inc" script). Plus, I replaced "Gdbm" in the Cache::init method by "TextFile" or "Sdbm" as appropriate. Sorry this got lengthy ... I wonder if any of you ran into this once and has a hint for me. I'm stuck :( And sorry, I am a beginner, maybe I miss something obvious. Thanks in advance! Walter

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Xotcl June 2005