[Xotcl] Re: XOTcl is great!!

[Gustaf Neumann]

Taral schrieb:

> Well, I will be in touch with you guys on further development on my side.

good. i'll send you soon a version of xotcl with the "...foward ... 
expr..." problem resolved, if you
are interested.

> By the way, I can not resist myself asking you guys about testing done 
> for XOTcl. I'm planning to use it for implantable Medical Device 
> hard-real time firmware system where bugs are not allowed at all. 
> Reading you note about the bug in expr method, do you mind giving me a 
> small update on what type of testing is done on this library and how 
> much stable is it from your experience?

we have a constantly growing regression test suite. in general i think 
it is generally
perceived that xotcl has a very high stability. there is at least on 
company that depends
on xotcl  in their multi threaded mission critical product; we use xotcl 
in our e-learning
environment, which is (based on publications) the most intensely used 
e-learning
system on universities world wide (up to more than 4 mio requests from 
registered
users per day). The OACS community has recentlyTIPed that xotcl should 
become
part of every standard OACS installation.

before every release, we run all the regression test and complex systems 
around and we
send pre-releases to core users. If you look at the changelog you will 
see that most bugs
are either in "new features" or show up in "erroneous xotcl code". In 
your situation i would
certainly do my own testing with my code and xotcl before burning the 
code into proms.
The community will help you with problems, if you are interested in 
commercial support,
we have founded recently a small company for providing support for 
various of our
research products.

> Are there any plans to provide more of object relation management 
> functionality in the library itself? When are you planning the next 
> release?

in the next weeks.

> I was wondering about whom I'm talking to. You guys are obviously from 
> Germany/Austria based on my guess from your email address. It would be 
> nice to know you guys little more to help the communication. Do you 
> guys have any personal webpage? I don't have one myself :(   But now I 
> feel like I should have one. So I will try to put up one sometime soon.

you will find my face (and uwe's) easily via google

best regards
-gustaf neumann

>
> On 9/5/05, *Gustaf Neumann* <neumann at wu-wien.ac.at 
> <mailto:neumann at wu-wien.ac.at>> wrote:
>
>     Taral schrieb:
>
>     > Hello,
>     >
>     > I recently came across XOTcl and found it very very useful. I am
>     > working on optimizing some legacy compiler code which is written in
>     > TCL. I would like to make it object-oritented and so I started
>     using
>     > XOTcl. So far I have found aouut 90% reduction in execution time.
>     > Overall I'm getting great performance by using XOTcl.
>
>     wow, this is an impressive number; good to hear that.
>
>     > I would like to Thank You guys for writing such a great library.
>     >
>     > Of course I have couple of questions for you. I will really
>     appreciate
>     > it if you can help me here.
>     >
>     > (1) Is there any way to all the objects or instances based on
>     > parameter value? For example, I would like to request object
>     names of
>     > all objects where given parameter's value is equal to 5.
>
>     There is no built-in support for this. a straigthforward approach
>     is the
>     following which might
>     be sufficient in many situations:
>
>     ===========
>     # define method expr for all Objects, the operands are taken from
>     # the instance variables
>     Object instforward expr -objscope
>
>     # define method select with some abitrary tcl expression. All objects,
>     # for which the expression returns 1 are returned
>     Class instproc select {expr} {
>       set result_list [list]
>       foreach o [my allinstances] {
>         if {![catch {$o expr $expr} result]} {
>           puts "$o expr {$expr} -> $result"
>           if {$result} {
>         lappend result_list $o
>           }
>         }
>       }
>       return $result_list
>     }
>     ===========
>
>     so, now we define a view classes and objects with some instance
>     variables
>
>        Class C -parameter {{x 10}}
>        Class D -superclass C
>
>        C c1
>        C c2 -x 11
>        D d1 -x 100
>        D d2
>        D d3
>        d3 unset x
>
>     finally, we try it out with some demo queries
>
>        foreach q {
>          {$x > 10}
>          {$x >= 10}
>          {$x < 1}
>          {[string match *00* $x]}
>        } {
>          puts "C select $q --> {[lsort [C select $q]]}\n"
>        }
>
>     Note that in this example, all instances of C are checked for the
>     expression, if
>     you use "... [Object select {$x > 10}]", all objects will be checked.
>
>     This approach might be good enough for small examples and medium
>     speed requirements. If you have larger number of objects, and you
>     cant
>     restrict the query to smaller classes, you should try to build an
>     index
>     based on associative arrays, which could replace the "allinstances"
>     in the code above.
>
>     > (2) Do you have more example code pieces? I would like to see more
>     > sample implementation to help me with the syntax. I'm also learning
>     > TCL language at the same time using XOTcl :)
>
>     i am sure, you have seen the tutorial and the examples in xotcl*/apps
>     and xotcl*/library. There are a few more on:
>
>       http://mini.net/tcl/XOTcl
>       http://wiki.tcl.tk/references/10971!
>
>     > (3) Is there any way to represent relationship across two
>     classes? For
>     > example, Class A is related to Class B with one-to-many
>     relationship.
>
>       a few class/class relations and object/class relations are
>     maintained
>     by xotcl (e.g. superclass,
>       class, mixins).  A start point might be ::xotcl::Relations,
>     which  is
>     used to implement a
>       uniform interface to mixins (and instmixins ...), which allows to
>     specify "... mixin add ...",  #
>       "... mixin delete ...", "... mixin set ...", etc. In principle, the
>     same interface could be used
>       for application level relations as well...
>
>     In current applications, the classes use and maintain a list of
>     related
>     object/classes.
>     Often, it is conveniant to use aggregations to express 1:1 or 1:n
>     relationships.
>
>     > (4) If there is a way to define relationship, is it possible to
>     query
>     > objects of classes in the relationship? For example, I would like to
>     > get all the objects of Class B related to given object of Class A
>     > (like a1) across given one-to-many relationship. In this case result
>     > would be list of object handles of Class B that matches based on
>     given
>     > primary key (identifier) value between class A and B.
>
>     a good key identifier is the object name. see the following snipplet,
>     how such behavior
>     could be obtained. We define class A, which maintains the relationship
>     to some other
>     objects. if an instances exists that relates e.g. to object c1, we
>     could
>     check there some
>     properties with expr like above...
>
>     Class A -parameter {relates_to}
>
>     A a1
>     A a2
>
>     a1 set relates_to {c1 c2}
>
>     foreach o [A allinstances] {
>       catch {
>         if {[lsearch -exact [$o relates_to] c2] > -1} {
>           puts "could check $o"
>         }
>       }
>     }
>
>     hope theses examples help a little.
>
>     -gustaf
>
>     PS: when i was writing this mail i saw that the classtack information
>     within methods called via the method "expr" is not correct. It will
>     be fixed in the next release....
>
>     >
>     > Please provide some guidance to implement above functionality
>     using XOTcl.
>     >
>     > Thanks a lot in advance.
>     >
>     > May be in future I would like to contribute to XOTcl. I wish to
>     be in
>     > touch with you guys.
>     >
>     > Regards,
>     > Taral
>
>
>