Xotcl July 2007

xotcl@alice.wu.ac.at

5 participants
5 discussions

two crashy issues // 1.5.x
by Stefan Sobernig 24 Jul '07

24 Jul '07

I attached two scripts, each reproducing bugs I found with most recent versions of XOTcl (1.5.2/1.5.3). Bug -1-: Argument declarations to proc/instproc containing a single empty tcl string yield a segfault/bus error. Bug -2-: Nesting objects through per-object evals (evals in the object scope) yields segfaults/bus errors under certain conditions. all the best, //stefan -- Stefan Sobernig Institute of Information Systems and New Media Vienna University of Economics Augasse 2-6 A - 1090 Vienna `- +43 - 1 - 31336 - 4878 [phone] `- +43 - 1 - 31336 - 746 [fax] `- stefan.sobernig(a)wu-wien.ac.at <mailto:stefan.sobernig@wu-wien.ac.at> `- ss(a)thinkersfoot.net <mailto:ss@thinkersfoot.net> package req XOTcl # / / / / / / / / / / / / / / / / / / / / / # Bug trace -1- # empty tcl string as argument declaration # - - - # stefan.sobernig(a)wu-wien.ac.at # reproducable/observed for 1.5.2/1.5.3 ::xotcl::Object o o proc m1 {{}} {;} # / / / / / / / / / / / / / / / / / / / / / # Bug trace -2- # Nesting through "objscoped" evals # - - - - - - - - - - - - - - - - - - - - - # stefan.sobernig(a)wu-wien.ac.at # reproduceable/observe for 1.5.2/1.5.3 package req XOTcl namespace import ::xotcl::* Object o o eval {set x [::xotcl::self]} o set x o eval {set x [::xotcl::self]::nested} o set x set cmd {::xotcl::Object [::xotcl::self]::nested} o eval $cmd # yields bus error # - - - # However, strange enough, when uncommenting lines 12-14 # the nested object is created without any # fatal error?! Object o # o eval {set x [::xotcl::self]} # o set x # o eval {set x [::xotcl::self]::nested} # o set x set cmd {::xotcl::Object [::xotcl::self]::nested} o eval $cmd # works as expected # - - - # Injecting a requireNamespace makes # the issue vanish, even with the # pre-nesting operations being # evaluated Object o o eval {set x [::xotcl::self]} o set x o eval {set x [::xotcl::self]::nested} o set x o requireNamespace set cmd {::xotcl::Object [::xotcl::self]::nested} o eval $cmd # works as expected # - - -

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Pre-release of xotcl 1.5.4
by Gustaf Neumann 23 Jul '07

23 Jul '07

Hi everybody, due to the reported problems, we provide a pre-release of xotcl 1.5.4. http://media.wu-wien.ac.at/download/xotcl-1.5.4.tar.gz Below is a list of the changes in this trunk since the release of xotcl 1.5.3. Ben, please check, if this solves your problem. Artur's case seems more complicated, i don't see the relation to the event loops in the fixes below. -gustaf neumann 2007-07-23 <Gustaf.Neumann(a)wu-wien.ac.at> * Pre-Release of XOTcl 1.5.4 2007-07-23: <Gustaf.Neumann(a)wu-wien.ac.at> * fixed a bug with empty argument names (Many thanks for Stefan Sobernig for reporting the bug) 2007-07-03: <Gustaf.Neumann(a)wu-wien.ac.at> * allow to call methods from the class to be called from slot objects (Many thanks for Nico L'INSALATA for noting this problem). 2007-06-05: <Gustaf.Neumann(a)wu-wien.ac.at> * Fixed spelling mistakes in the tutorial (Many thanks to Robert Hicks for reporting) 2007-05-27: <Gustaf.Neumann(a)wu-wien.ac.at> * Fixed potential error with default values for parameters starting with a "-". (Many thanks to Shishir Ramam for reporting) 2007-03-16: <Gustaf.Neumann(a)wu-wien.ac.at> * fixed a bug where a Tcl call adds a namespace to an object, but xotcl did not notice it. (Many thanks for Stefan Sobernig for reporting the bug) 2007-01-14: <Gustaf.Neumann(a)wu-wien.ac.at> * fixing error message propagation for methods called via configure. (Many thanks for Kristoffer Lawson for reporting the bug) 2006-12-12 <Gustaf.Neumann(a)wu-wien.ac.at> * changing "test == " to "test =" as required by FreeBSD (many thanks to Martin Matuska for providing the patch) 2006-12-07 <Gustaf.Neumann(a)wu-wien.ac.at> * MinGW patches (many thanks to Martin Matuska for providing the patch)

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segmentation faults and bus errors
by Ben Thomasson 23 Jul '07

23 Jul '07

Hello again, I bring bad news. I am receiving seg faults and bus errors while running XOTcl code. I am running XOTcl 1.5.3 and Tcl 8.4 on both Linux x86 and OS X PPC. I received the errors randomly on both platforms. This started occuring when I reloaded the source code. At first I thought it was related to Tcl packaging, but I mostly removed calls to package require and package forget. Currently I just use source to load most files. I am writing code generation libraries and using Object eval so I may be doing new things with XOTcl. How should I go about debugging these seg faults? Are core dumps useful? I'll try to write a script that reproduces the problem, but I haven't really narrowed the problem down yet. Any help is much appreciated. Thanks, Ben

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Re: [Xotcl] parameters vs slots and use of "-initcmd"
by mail＠xdobry.de 05 Jul '07

05 Jul '07

>Strictly speaking, an application programmer does not have >to use parameter in the application program, therefore Artur is right. > >While the application program does not have to *define* slots, >it is hard to do something useful in xotcl without *using* slots >since methods like "superclass", "class", "mixin" etc. >are implemented as slots. > Thanks for precise explanations. I must confess that till now I have not consciously (bewußt) used slots. It is indeed very powerful construct and I have noticed that is used to implement of many of XOTcl features. One reason, why I do not use slots and complex parameters is that XOTclIDE has no support for it. I has not programmed it yet. I have no idea how to define or visualize slots in XOTclIDE in this way, that it suits to general concept. Now XOTclIDE has already a problem with versioning of class definition (creation body). Because definition bodies are not versioned like bodies of methods. Using slots is even more complex. Tutorial example: Class create A -slots { Attribute foo -default 1 -proc assign {domain var value} { if {$value < 0 || $value > 99} { error "$value is not in the range of 0 .. 99" } $domain set $var $value } } Normally XOTclIDE let you view, change and redefine all items separately. But in this example complex items like method-body are part of class creation. Is there a way to define such slots in iterative way. I have tried following code but it was not OK. Class A Attribute A::slot::foo this one seems to work A slots { Attribute foo } A::slots::foo proc assign {...} { .... } I miss also possibility to obtain slot definition per introspection. (similar to ::A info parameter) Probably one the only one way is own code (::A::slot::foo info body assign). Anyway! Probably one of possible usage of slots will be implementing MVC GUI Framework. Complex parameters could be used to connection GUI Code with Domain Code. Similar approach I know from Smalltalk VisualWorks Framework see also: http://www.martinfowler.com/eaaDev/uiArchs.html It use so called Attributes, which are objects and represent a simple value (like Integer, String, Date). UI-Controls can be connected to this attributes (per event framework). These attributes are members of domain objects. I have a question to another XOTcl users. I am not sure how urgent and important is the support of slots definition in XOTclIDE. So any information about it are welcome. Artur

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parameters vs slots and use of "-initcmd"
by Nico L'INSALATA (UniPI) 04 Jul '07

04 Jul '07

Hi everybody, my name is Nico and I'm new to XOTcl. After spending few weeks in understanding the basic concepts of the language, I decided to use it to model one component of the software I'm developing as part of my PhD project (basically, configuration of complex digital hardware macrocells). I've been attracted by XOTcl due to its "aspect oriented" features which are today very common in the hardware design industry. I need some clarifications regarding the use of Class parameters and Class slots (I will refer to v.1.5.2 of the XOTcl tutorial). Parameters are used throughout the introduction of the tutorial to model Class attributes, then slots are introduced in a later section. Are slots and parameters actually the same thing? Is there some reason to prefer one over the other? Anyway, I've started using slots and I got lost using the -initcmd feature. This is a "simplified" version of the code that "doesn't work" (i.e. I'm not able to make it work :-) ) Class my_class \ -slots { Attribute one -type integer -default { 0 } Attribute two -type integer -default { 0 } Attribute three -type integer -initcmd { if { [my one] > [my two]} { set _ 100 } else { set _ 101010 } } } The code doesn't work (of course!!) since [self] within initcmd has value "::my_class::slot::three". So, the question is: how do I refer to other attributes of the same class from within -initcmd { }? And secondarily, is it possible to associate -initcmd with an instproc of the class in which the attribute is being defined? e.g. an instproc of Class my_class Note that, to ensure things work properly, when instances of my_class are created both attributes "one" and "two" are initialized, while attribute "three" will also be refereed in a subsequent part of the script. This behavior is bizarre and potentially unsafe, but is dictated by another software components over which I have no control. Thank you very much for your attention! Nico

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Xotcl July 2007