William F Pokorny <ano### [at] anonymousorg> wrote:
> On 2/26/22 05:37, Bruno Cabasson wrote:
> > Thanks for the update! But what about Christoph?
>
> He's not been recently active is all I know.
>
> >
> ...
> >
> > HOWEVER, and despite that situation, the dictionary container gave me the idea
> > that it could be possible to imagine using them for classes, instances and some
> > fundamental Object Oriented features. I think that if it happens to be feasible
> > and if it happens to be usable without syntactic over-complexity or
> > non-readabiliy, I could be open the object-orientedness for POV-Sdl. It could
> > help for complex scenes, animation, whatever an object-oriented language is
> > handy (or necessary).
> >
> > So, I had it a try.
> >
> > AND I reached something quite fine (though it is just a Proof Of Concept until
> > now)...
> > I could implement :
> >      classes,
> >      instances,
> >      properties,
> >      methods,
> >      inheritance,
> >      overloading for contructors and methods,
> >      named parameters,
> >      new(), super(), instanceof() operators,
> >      type-ckecking,
> >      templates,
> >      and a few other minor OO features.
> >
> > Do you think it could be interesting for the POV community ? For fun, I named it
> > PROOF (Pov Ray Object Oriented Features).
>
> I like the acronym. :-)
>
> Certainly of interest, especially, as a way to flesh out ideas for a
> potential v4.0 SDL concepts/syntax.
>
> Ingo and jr in particular have been pushing ideas using the dictionary
> feature of v3.8/v4.0 over the pass 3-4 years. I also picked up TOK's
> newer dictionary based array statistics code as a stand alone
> arraystatistics.inc in my povr fork.
>
> ---
> Practically, you might come up against issues.
>
> Being based atop current parsers, performance a concern. As 'proof' of
> concept code this will matter less.
>
> To be sure you are aware. In 2018 and early 2019 Christoph was
> significantly changing the internals of the - then v3.8 - parser. At
> that point all development stalled for roughly 2 years starting in early
> 2019 until Christoph resumed working on POV-Ray for some months in 2021.
>
>
> On his return in 2021 he broke development into a v3.8 release path
> where he backed out code he considered to be too new for a near term
> v3.8 release. This included backing up the parser code to an earlier
> v3.8 state. The newest parser code still exists in the master branch
> which is now more or less aimed at v4.0. Both parser versions are -
> today - SDL / language feature equivalent (excepting a few fringe cases).
>
> However, last I knew, there were remaining parser issues in both
> implementations. IIRC there is at least one dictionary issue still in
> v3.8 fixed in v4.0.
>
> My personal povr branch is based on the newer (v4.0) version of the
> parser code which 'was' in v3.8 when I forked off the povr work. I
> 'believe' all the v4.0 parser 'bugs' of which I am aware have been
> addressed in the povr branch. In aspects the parser in povr has evolved
> into another 'internal' parser implementation - though again the SDL
> feature set is substantially v3.8/v4.0 equivalent today.
>
> New v4.0 SDL concepts/syntax and radical changes to the parser are not a
> presently a focus for me as I play with POV-Ray. I end up in the parser
> code when something needs to be understood / fixed - or it's otherwise
> in my way.
>
> ---
> Aside: Our existing scene description language (SDL) - as a language -
> supports certain object oriented 'concepts' today. Our implementation
> doesn't back them in a consistent way and so people tend to avoid the
> approach. The situation due internal coding choices and, often as not,
> bugs.
>
> For example, something like the following is supposed to work in POV-Ray
> today with fog, but it doesn't(1). The internal structure and code is
> all there - but for bugs.
>
> (1) - You can write similar parser clean code, but in the rendering
> details it very often isn't working.
>
> Using the povr fog example (povr's fog and related keywords somewhat
> different) and today's SDL:
>
> //...
> #declare Fog01 = fog {
>      type 1
>      distance 9.5
>      color Grey70
> }
> #declare Fog01_wTurb = fog {
>      Fog01
>      it_scale <1.6,0.16,1.6>
>      it_depth 2.1
>      it_octaves 5
>      it_omega 0.35
>      it_lambda 1.25
> }
> #declare Fog01_neg_it_depth = fog {
>      Fog01_wTurb
>      it_depth -2.1
> }
> #declare Fog01_blend_gamma = fog {
>      Fog01_wTurb
>      blend_gamma 2
> }
> #declare Fog01_inverse = fog {
>      Fog01_wTurb
>      inverse
> }
> #declare Fog01_range = fog {
>      Fog01_wTurb
>      range 7, 20
>      blend_gamma 2
> }
> #declare Fog03_rotate = fog {
>      Fog01_inverse
>      type 3
>      rotate z*45
> }
> //...
>
> Bill P.

Thanks for the update! I'll have a closer look to your povr fork (on github?).
But I still would like news from Christoph...

Let me talk a bit more about PROOF (object oriented layer over POV-Ray Sdl) in
'programming' thread.

PS : In the first place, I named it SLOPE : Syntactic Layer Over Povray and
Extensions...).

Bruno

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