Xotcl December 2000

xotcl@alice.wu.ac.at

8 participants
18 discussions

problem: filter disappears if instproc redefined
by seva＠design.kiev.ua 28 Dec '00

28 Dec '00

Hello I'm working on real-life application, which controls some hardware devices throw network protocol. For now this application consist of several instances of some objects, which implements FSM (finite state machines) of hardware devices. Now it is implemented using Itcl, but I need possibility to change fsm states and implementation without restarting application. Itcl does not allow me to do this, so I decided to switch to XOTcl. I split my application in several source files. Each of files implements one of fsm's or helper functions, and when I need to change logic of work, i simply source all files. There are several problems with this: 1) when I execute command Class Some, previous instance of this class deleted, and all objects move to ::Object class. This problem I solve by using filter for create command on ::Object (idea stolen from recoverypoint class :)) ). But with that second problem arrives: 2) when some instproc used as a filter, and redefined, it's filter become inactive. (so first problem arrives again, when I source recover.tcl which has recoverfilter definition) after setting filter again, all works as expected Hope for your help :)) Example code: ----------------- a.xotcl ----------------- #!/usr/local/bin/tclsh8.2 package require XOTcl Object instproc filter {args} { puts "filter: [self] [[self] info calledproc]" next } Object filter filter puts "Object test" Object test puts "test set a a" test set a a puts "Object instproc filter" Object instproc filter {args} { puts "new filter: [self] [[self] info calledproc]" next } puts "test set a a" test set a a puts "Object filter filter" Object filter filter puts "test set a a" test set a a ----------------------------------------- Result: Object test filter: ::Object test filter: ::Object create test set a a filter: ::test set Object instproc filter filter: ::Object instproc test set a a ^^^^^^^^^^^^^^^ unfiltered Object filter filter test set a a new filter: ::test set new filter: ::@ destroy new filter: ::test destroy

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Some fixes to xodoc
by Kristoffer Lawson 21 Dec '00

21 Dec '00

Attached to this post I have a slightly fixed version of xodoc. I did the following corrections/additions: - Added space between the different "sections" of class descriptions. Ie. as in the following case: @ Class Foo { description {blah} errors {foo} } It would just stick 'description' and 'errors' on to the same line. - Added functionality to handle optional procedure arguments. Ie. as in thee following case: @ Foo instproc {arg1 {arg2 ""}} {} Now it marks arg2 as optional with the standard Tcl syntax, and also automatically specifies the default value along with the description. - Added some special handling for the section 'errorCodes' in a class. These error codes are the things you can give with the [error] command to give a code to the error, so catching is easier. Ie. the following: @ Class Foo { description {blah} errorCodes { MyAppError { Used for sending errors my application specifically creates. } } } What I didn't do: I was going to add an extension facility so that applications could specify their own handler-objects for certain special sections. Like in Class Foo above I might have a section {Attribute Aliases} in addition to errorCodes (as I do). I would like to specify a AttrAliasDocHandle object, for example, which would have the method "toHtml" (if outputting HTML) that gets called when the section {Attribute Aliases} is encountered, with the data passed to it as an argument. This would then return a nice HTML table documenting my aliases. The syntax to create an extension might be something like this: @ @DocExtension Class {Attribute Aliases} AttrAliasDocHandle I would have done this myself but it's already late (3am) and I really desperately need to continue my real work. If anyone feels like implementing that, then feel free... Otherwise I'll just have to get back to it at some later time :-( - ---------- = = ---------//--+ | / Kristoffer Lawson | www.fishpool.fi|.com +-> | setok(a)fishpool.com | - - --+------ |-- Fishpool Creations Ltd - / | +-------- = - - - = --------- /~setok/

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Bug in xodoc
by Kristoffer Lawson 20 Dec '00

20 Dec '00

It seems to ignore the last line of a file if that last line doesn't end with a newline but with an EOF. Probably easy to fix so I might do it myself (as I'm planning to look through the source myself to add some bits). - ---------- = = ---------//--+ | / Kristoffer Lawson | www.fishpool.fi|.com +-> | setok(a)fishpool.com | - - --+------ |-- Fishpool Creations Ltd - / | +-------- = - - - = --------- /~setok/

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Xotcl in CVS
by Laurent Duperval 19 Dec '00

19 Dec '00

Hi, Is there a CVS repository for xotcl? L -- MY EMAIL ADDRESS HAS CHANGED --> UPDATE YOUR ADDRESSBOOK Laurent Duperval "Montreal winters are an intelligence test, Netergy Networks - Java Center and we who are here have failed it." Phone: (514) 282-8484 ext. 228 -Doug Camilli mailto:laurent.duperval@netergynet.com Penguin Power!

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Using source with the xodoc tool / Debian
by Kristoffer Lawson 19 Dec '00

19 Dec '00

I haven't yet got round to upgrading to 0.83 and the upgraded xodoc tool, but I'd like to know how it reacts to splitting up a package into several files? Ie. I have one large file with lots of classes but to structure it more neatly I am moving parts of it into other files with the same package name so that "package require" gets all of them. Will this affect the operation of xodoc? Specifically I'd like to know what happens when using the "@ File" system as I'd probably like to document each file separately like that. In addition all the classes in the different files are evaled into the same namespace, so xodoc should handle this too. On another issue we have made Debian packages of XOTcl (0.82, but 0.83 is on the way) if someone is interested.. They're not extensively tested but they seem to work on the machines here. Probably candidates for merging into the official Debian system at some later time. - ---------- = = ---------//--+ | / Kristoffer Lawson | www.fishpool.fi|.com +-> | setok(a)fishpool.com | - - --+------ |-- Fishpool Creations Ltd - / | +-------- = - - - = --------- /~setok/

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implementing delegation in Xotcl?
by Catherine Letondal 18 Dec '00

18 Dec '00

Hi, I have a very philosophical question :-) I would like to replace inheritance by delegation for some classes' instances. e.g: Class C -parameter {delegate} # instead of Class C -superclass D C c -delegate a where a is an object of another class, say class A. Delegation means that: - next should call the delegate's proc/instproc - set, instvar would give access to delegate's variables (this is one of the classical delegation mechanisms/behaviour I believe?) I have tried 3 methods, but neither work! 1) with a filter on C, which branch the methods calls to the appropriate location. the filter is defined in init: C filter CFilter C instproc CFilter args { ::set m [[self] info calledproc] [self] instvar delegate if { ([C info instprocs $m] != "") || ([[self] info procs $m] != "") } { puts "CFilter m=$m I do it myself" next } elseif { [info exists delegate] && ($m == "set" || $m == "instvar") } { puts "CFilter m=$m I delegate it to $delegate" eval $delegate $m $args } elseif {[info exists delegate] && [[$delegate info class] info instprocs $m] != ""} { puts "CFilter m=$m I delegate it to $delegate" eval $delegate $m $args } else { puts "I dont know (m=$m), I call next" next } } 2) with a mixin on c in init: [self] mixin [$delegate info class] 3) with both => problem with filter only (1) : - next does not work the way I want (it does not call the delegates) - set of delegates' variables works, but instvar don't => problem with mixin only (2) - as the delegate's class is the mixin, it's it's methods which are always called first (but I want the delegate's methods to be called only when not existing for the class or when calling next) - I need a method in the delegate's class for every method int the class - delegate's variables are not available, of course (since I only use the class of the delegate to inherit methods) => mixin+filter (3) (example below) : - instvar does not work Does someone have ideas and opinions about this? Has someone already tried? I don't remeber having found something about it in Xotcl's papers (maybe I'm wrong?). Thanks! -- Catherine Letondal -- Pasteur Institute Computing Center +------------------------------------------------------------------------------------- Example of code for solution (3): # delegation with mixins+filter # object a of class A will be used as delegate for C Class A A instproc f1 args { puts "A f1 I am: [self] from class: [[self] info class]" } A instproc f3 args { puts "A f3 I am: [self] from class: [[self] info class]" } A a a set x 10 Class C -parameter {delegate} C instproc init args { [self] instvar delegate if {[info exists delegate] && [::Object isobject $delegate]} { puts "adding [$delegate info class] as a mixin for [self]" [self] mixin [$delegate info class] puts "adding CFilter as a filter for [[self] info class]" [[self] info class] filter CFilter } } C instproc f2 args { puts "C f2 I am: [self] from class: [[self] info class]" } C instproc f3 args { puts "C f3 I am: [self] from class: [[self] info class]" puts "calling next" next } C instproc CFilter args { ::set m [[self] info calledproc] if {$m == "CFilter"} { next } [self] instvar delegate if { ([C info instprocs $m] != "") || ([[self] info procs $m] != "") } { puts "CFilter m=$m I do it myself" next } elseif { [info exists delegate] && ($m == "set" || $m == "instvar") } { puts "CFilter m=$m I delegate it to $delegate" eval $delegate $m $args } elseif {[info exists delegate] && [[$delegate info class] info instprocs $m] != ""} { puts "CFilter m=$m I delegate it to $delegate" eval $delegate $m $args } else { puts "I dont know (m=$m), I call next" next } } C d -delegate a d proc f4 args { [self] instvar x puts "f4 [self] x: $x" } Try: d f1 d f2 d f3 d f4

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instproc vs proc
by Laurent Duperval 13 Dec '00

13 Dec '00

Hi, When do you use instproc vs. proc? I'm looking at the code I've written so far, and it's all instproc, I make no use of proc at all. So I'm wondering if it's because proc isn't used often or because I'm missing out on something really cool. L -- MY EMAIL ADDRESS HAS CHANGED --> UPDATE YOUR ADDRESSBOOK Laurent Duperval "Montreal winters are an intelligence test, Netergy Networks - Java Center and we who are here have failed it." Phone: (514) 282-8484 ext. 228 -Doug Camilli mailto:laurent.duperval@netergynet.com Penguin Power!

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Re: [Xotcl] Object mixin with passing init args ?
by Zoran Vasiljevic 13 Dec '00

13 Dec '00

------Original Message------ From: <uwe.zdun(a)uni-essen.de> To: Gustaf.Neumann(a)wu-wien.ac.at Sent: December 13, 2000 11:33:51 AM GMT Subject: Re: [Xotcl] RE: [Xotcl] Re: [Xotcl] Object mixin with passing init args ? Wow ! After all this, what should be the best way to go ? Patch xotcl.c and fix the mixin args? Rewrite the app and wait until there is a general-elegant-allmighty solution ? What do you think ? Zoran ______________________________________________ FREE Personalized Email at Mail.com Sign up at http://www.mail.com/?sr=signup

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RE: [Xotcl] Re: [Xotcl] Object mixin with passing init args ?
by Zoran Vasiljevic 13 Dec '00

13 Dec '00

------Original Message------ From: <uwe.zdun(a)uni-essen.de> To: Zoran Vasiljevic <zoran(a)munich.com> Sent: December 13, 2000 9:55:56 AM GMT > 2. However, in the "mixin" case we could enable argument passing, > because "mixin" has just one argument? The rest could be passed > to "init". any objections? obj mixin Foo arg1 arg2 arg3 would pass arg1-arg3 to init of Foo. Right? obj mixin [list Foo Bar] arg1 arg2 arg3 would pass arg1-arg3 to init of Foo AND of Bar. Right again? Is so, then I think it should be done, if possible. 0.85 ? 0.9 ? Cheer's, Zoran ______________________________________________ FREE Personalized Email at Mail.com Sign up at http://www.mail.com/?sr=signup

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Re: [Xotcl] Object mixin with passing init args ?
by Zoran Vasiljevic 13 Dec '00

13 Dec '00

------Original Message------ From: Gustaf Neumann <Gustaf.Neumann(a)wu-wien.ac.at> To: Zoran Vasiljevic <zoran(a)munich.com> Sent: December 13, 2000 10:41:01 AM GMT Subject: [Xotcl] RE: [Xotcl] Re: [Xotcl] Object mixin with passing init args ? > from the implementation point of view this is not a big issue. >however, from my experience, i should note that i switched from a >style of "passing arguments to init" to the "-parameter style of >configuring objects", which is in almost all cases the more elegant >solution. <snip> Yes. I must admit that your reasoning is correct. One gets wierd constructs if thinking about all possible situations. But, let me explain my issue. There may be another solution. I have couple of classes impementing tree-like operations on XML files and regular filesystems. Both classes share the same abstract class, Tree (when I think of the Storage implementation in XOTcl distro, then this case would be very similar). Now, each of (Xml/Ufs) classes are mixed-in the general Tree object. Each of them needs a different argument pointing to a xml-file/file-directory where to hook on. Consider ... Class Tree ;# has abstract methods mostly Class XmlTree -superclass Tree ;# implements above methods Class UfsTree -superclass Tree ;# ... XmlTree instproc init {xmlFile} {....} UfsTree instproc init {rootDir} {....} Tree t t mixin XmlTree /path/to/xmlfile.xml ;# use the Xml driver t mixin UfsTree /some/dir ;# switch to filesystem driver Dang ! Showstopper, since I cannot pass arg to XmlTree/UfsTree. Any suggestions ? ______________________________________________ FREE Personalized Email at Mail.com Sign up at http://www.mail.com/?sr=signup

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Xotcl December 2000