[vtk-developers] Tcl wrapping and output array arguments

[Berk Geveci]

I am not against this either but I'd like to remind people that there are 2
VTK books that still use Tcl for their examples. We probably need to figure
out how to transition those before discontinuing Tcl support.

-berk


On Fri, Mar 20, 2015 at 8:21 PM, Will Schroeder <will.schroeder at kitware.com>
wrote:

> Personally I have no real attachment to Tcl and can see queuing it up for
> deprecation at some point. I'd like to get the community more widely
> involved in this decision in terms of when, etc. since there may be some
> significant applications out there still using it and we want to minimize
> community disruption. There's a lot going on now anyway with the gitlab and
> OpenGL2 changes so this is not likely to happen anytime soon.
>
> W
>
> W
>
> On Fri, Mar 20, 2015 at 7:38 PM, Andrew Maclean <andrew.amaclean at gmail.com
> > wrote:
>
>> David, David, Will, John
>>
>> I remember the TCL discussion, maybe the time has come to raise dropping
>> it again. I would certainly support that. It was useful before Python was
>> widely used but nowadays I think C++/Python/Java programmers would rarely
>> (if ever) need to use it. Personally I find it difficult to understand and
>> use.It is not a modern language,
>>
>> One of the reasons TCL was useful in the "old days" was that a lot of the
>> testing code was written in it but that is hardly relevant now since we
>> converted almost all of it into Python.
>>
>> Will, I did translate most of the VTK Textbook exercises into Python soon
>> after that discussion (way back in 2012). There were a couple that I
>> couldn't convert, see the attached document for a summary of what I have
>> done.
>>
>> I'll look at converting TestSetGet and TestEmptyInput to python.
>>
>> Regards
>>    Andrew
>>
>>
>>>
>>> ---------- Forwarded message ----------
>>> From: David Lonie <david.lonie at kitware.com>
>>> To: David Gobbi <david.gobbi at gmail.com>
>>> Cc: VTK Developers <vtk-developers at vtk.org>
>>> Date: Fri, 20 Mar 2015 09:00:01 -0400
>>> Subject: Re: [vtk-developers] Tcl wrapping and output array arguments
>>> On Thu, Mar 19, 2015 at 5:54 PM, David Gobbi <david.gobbi at gmail.com>
>>> wrote:
>>>
>>>> On Thu, Mar 19, 2015 at 2:28 PM, David Lonie <david.lonie at kitware.com>
>>>> wrote:
>>>>
>>>>>
>>>>> My questions:
>>>>>
>>>>> 1) Is the concept of an "output array argument" even supported by Tcl?
>>>>>
>>>>
>>>> Yes.  I imagine something like this could create a new array called
>>>> "bounds":
>>>>
>>>>   % mapper GetBounds renderer bounds
>>>>
>>>>
>>>>> 2) If so, how can I teach the wrappers about it?
>>>>>
>>>>
>>>> Adding things like this to Tcl is easier than for Java or Python, but
>>>> it's more than an afternoon's work.  I believe that Tcl will already wrap
>>>> this method, but the wrapped method will expect 6 values as input, instead
>>>> of expecting one name for an output array that it should create.  Because
>>>> the wrappers can't really tell whether "double[6]" is meant to be used for
>>>> input or output, the method will actually have to be wrapped twice, once
>>>> for input, and once for output.  There are undoubtedly some tricky
>>>> complications that I haven't though of, however.
>>>>
>>>
>>> Unfortunately, the method is not wrapped currently (according to the
>>> generated vtkPropTcl.cxx file, anyway).
>>>
>>> And perhaps the most curious question from my point of view,
>>>>>
>>>>> 4) Why do we still provide Tcl bindings in 2015?
>>>>>
>>>>
>>>> Because they're cool!  Actually, at this point I'm fine with them going
>>>> away, but I'd still like to keep Tkinter (which works just fine without the
>>>> Tcl wrappers).
>>>>
>>>
>>> The general consensus from the developers I've talked to out here is the
>>> same -- we'd love to see Tcl go. I had a heck of a time trying to even find
>>> a developer who remembered enough about Tcl to begin tracking down this
>>> issue before I posted on the mailing list...and this includes the people
>>> who wrote the original Tcl wrappers ;)
>>>
>>>
>>>> But seriously, can we deprecate them for 6.3?
>>>>>
>>>>
>>>> Any volunteers to convert TestSetGet and TestEmptyInput to python?
>>>>
>>>
>>> Looks like Andrew has volunteered :D
>>>
>>> I found this discussion from around v6.0's release:
>>>
>>>
>>> http://vtk.1045678.n5.nabble.com/Modularization-Context2D-and-Tcl-td5594211.html
>>>
>>> Looks like there was a fair bit of resistance against dropping Tcl 2-3
>>> years ago, so I'm not sure how worthwhile it would be to push for this now.
>>>
>>> But if supporting such a simple method like this requires "more than an
>>> afternoon's work" to teach Tcl to understand it, it sounds like more of a
>>> burden than a benefit. From what I'm seeing, it's a non-trivial amount of
>>> work to keep Tcl working with new APIs and few active developers actually
>>> remember Tcl well enough to work on it. Not to mention that in my few years
>>> here at Kitware, I've never actually come across an active project that
>>> uses Tcl -- not to say they don't exist, but they seem quite rare these
>>> days.
>>>
>>> In any case, decisions like these are beyond me. I'm just a C++ guy
>>> trying to add a simple new method to the library :-)
>>>
>>> Dave
>>>
>>>
>> --
>> ___________________________________________
>> Andrew J. P. Maclean
>>
>> ___________________________________________
>>
>
>
>
> --
> William J. Schroeder, PhD
> Kitware, Inc.
> 28 Corporate Drive
> Clifton Park, NY 12065
> will.schroeder at kitware.com
> http://www.kitware.com
> (518) 881-4902
>
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