"jr" <cre### [at] gmailcom> wrote:

just to clarify.

> ...
> think that I'd hoped for a situation where POV-Ray proper and (eventually) all
> forks supply a version.inc which tells, basically, whether or not "official";

I don't mean official as in compiled-by.  "official" returned from a version.inc
would tell me that the scene's SDL will work as detailed in the official
wiki/docs.

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William F Pokorny <ano### [at] anonymousorg> wrote:

> Lastly, an aim is that the 'forkversionhook.inc' file be extensible.
> That, in approach, its able to accommodate multiple forks / patches /
> branches. In other words, in just supporting multiple forks over time,
> it could grow substantially in size. I see no reason this file cannot be
> shared - at least to some degree - across forks.

It's just a text file.  And it's for POV-Ray - so just how many edits and forks
there will be ....   I mean, even if it was War & Peace in ASCII, it still
wouldn't be that large of a file.
A functional option, one I'm not sure I like ATM, is to have a version
_directory_ with a tree of inc files that the main file includes and executes -
only if they exist.   Then the individual users can grow or prune the contents
of the directory as they see fit.  Still think that for any given fork, a
generic named file should call the most recent name-with-version.inc
That way people can search the forums (fora?) and easily see if they have the
proper/latest version of what they're looking for.   Even if it's just File1,
File2, File3 ....   it at least makes the filename different, and gives an
easily identifiable sequential progression.

> In general, I think I'll reduce the f_odd() visibility. No reason day to
> day users need to know this the internal 'hook'.

You can have silent and verbose modes.
Silent is for everyday use, verbose can be for anyone looking to figure
something out.   Just set a flag, look for the presence of a dummy file...


As for constant, function, and macro names, there's a school of thought that if
your names are descriptive enough, the code is "self documenting" and doesn't
require comments.   I think this works well for code that isn't long on the
first few (re)write(s) and only gets edited every so often.   Using long names
in day to day use is a DRAG.

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On 2/15/22 02:11, jr wrote:
> "jr" <cre### [at] gmailcom> wrote:
> 
> just to clarify.
> 
>> ...
>> think that I'd hoped for a situation where POV-Ray proper and (eventually) all
>> forks supply a version.inc which tells, basically, whether or not "official";
> 
> I don't mean official as in compiled-by.  "official" returned from a version.inc
> would tell me that the scene's SDL will work as detailed in the official
> wiki/docs.
> 

Thinking.

Nobody can truly declare particular behavior without being the one 
providing a pre-compiled POV-Ray package. Further, the compiled program 
needs to be linked with, or use, fixed library dependencies. The 
official status is indicated by the POV-Team only for windows binaries 
where the current libraries are part of the git tracked code base.

Those binaries only state official status in the text output while 
setting up the parser to die on the 'unofficial' keyword. There isn't a 
way to query official / unofficial status from within the SDL.

We want to be able to set up scenes / includes with conditionals so we 
can run compiles from nominally unmodified source alongside forks like 
povr. This rules out the use of the 'unofficial' keyword for starters.

We also want something like 'unofficial' which dies for non-windows 
POV-Team provided binaries where we know the code will only run with a 
given fork(2).

I didn't call 'forkversion.inc' 'version.inc' to allow for an official 
POV-Team shipped 'version.inc'.

I suppose OK for forks to provide 'version.inc' files ahead of it 
potentially existing in POV-Team releases. Attached two povr include 
files in 'version.inc'(1) and 'forkversion.inc'. The latter with 
additional updates - shorter names, rewording, etc.

Comments welcome.

Aside: I'm unsure when / if to change the povr code to force all 
incoming SDL to run strictly at v3.8+. Internally, I've slowly been 
tossing code for backward compatibility into the bit bucket. V3.8+ SDL 
is all I intend to support. However, as many are still working with 
older releases, scenes and includes, I've been maintaining the parser in 
a state that allows earlier version settings. It's useful when looking 
at posted issues...

Bill P.

(1) - Uses file_exist for 'forkversion.inc' / 'version.inc', which can 
be problematic in the way file_exist with includes can be. However, I 
see no better method for a backward compatible 'version.inc'.

(2) - Thinking with povr I'll now use both 'unofficial' and code like:

#if (file_exists("version.inc"))
     #include "version.inc"
#end
#if (!Fork_povr)   // This POV-Ray SDL code requires the povr fork.
     #error "This POV-Ray SDL code requires the povr fork."
#end

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Attachments:
Download 'version.inc.txt' (4 KB) Download 'forkversion.inc.txt' (5 KB)

On 2/15/22 07:07, Bald Eagle wrote:
> It's just a text file.

True. It's also an include which the parser must digest. With animations 
the parser eats all includes, again, for each frame. Though users often 
include .inc files by the handful(1), being more selective about what 
needs to be included is more efficient.

I'll let your other ideas and thoughts bang around in my head for a while.

Bill P.

(1) - Via stdinc.inc as often as not.

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hi,

William F Pokorny <ano### [at] anonymousorg> wrote:
> ...
> There isn't a
> way to query official / unofficial status from within the SDL.

yet.


> We want to be able to set up scenes / includes with conditionals so we
> can run compiles from nominally unmodified source alongside forks like
> povr. This rules out the use of the 'unofficial' keyword for starters.
>
> We also want something like 'unofficial' which dies for non-windows
> POV-Team provided binaries where we know the code will only run with a
> given fork(2).
>
> I didn't call 'forkversion.inc' 'version.inc' to allow for an official
> POV-Team shipped 'version.inc'.

chain-loading via 'file_exists()' is nice + "clean" (imo).


> ...
> Comments welcome.
>
> Aside: I'm unsure when / if to change the povr code to force all
> incoming SDL to run strictly at v3.8+. Internally, I've slowly been
> tossing code for backward compatibility into the bit bucket. V3.8+ SDL
> is all I intend to support. However, as many are still working with
> older releases, scenes and includes, I've been maintaining the parser in
> a state that allows earlier version settings. It's useful when looking
> at posted issues...

it would be interesting to see proposals for an updated v4+ SDL.

out of interest, how difficult would it be to have two separate parsers?  one
for pre 3.7/8 compatibility, one for newer style.  (I'm guessing that the
executable would not be all that much larger, and separation might bring other
benefits)


have only spent a few minutes looking over the attached, seem ok (bar copy/paste
typos 'str_var' in 'forkversion.inc'.)


regards, jr.

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On 2/17/22 02:39, jr wrote:
> chain-loading via 'file_exists()' is nice + "clean" (imo).
> 

I'm not completely sure I'm following what you mean by chain-loading?

I've adopted the use of file_exists() on deciding to ship a version.inc 
with povr. The overall implementation is done in a 
scene->version.inc->forkversion.inc way. Is this what you mean by 
chain-loading?

---
file_exist() is one of those things which is clean until it's not. :-)

Think about how we've often shipped binaries intended to run on a 
earlier install base. There is build infrastructure to support this 
model of update. A model somewhat workable because official POV-Ray 
supports backward compatibility. It's problematic in that to safely 
align with any given binary you need the binary's includes too - 
something that in POV-Ray proper requires a full install.

Think too about how the search path is user modifiable.

Anyhow, it's the method we have. I agree too for normal users with a 
single installation of POV-Ray, and relatively constant include files, 
file_exist is safe enough.

> 
>> ...
>> Comments welcome.
>>
>> Aside: I'm unsure when / if to change the povr code to force all
>> incoming SDL to run strictly at v3.8+. Internally, I've slowly been
>> tossing code for backward compatibility into the bit bucket. V3.8+ SDL
>> is all I intend to support. However, as many are still working with
>> older releases, scenes and includes, I've been maintaining the parser in
>> a state that allows earlier version settings. It's useful when looking
>> at posted issues...
> it would be interesting to see proposals for an updated v4+ SDL.

Practically, I don't think I've got the bandwidth for anything 
revolutionary in the povr fork.

It would probably be TCL if I do get around to trying something radical. 
I have a lot of that going today - as you know - but the implementation 
writes SDL. In other words, it still leans on the current SDL parsers.

> 
> out of interest, how difficult would it be to have two separate parsers?  one
> for pre 3.7/8 compatibility, one for newer style.  (I'm guessing that the
> executable would not be all that much larger, and separation might bring other
> benefits)
> 

My up front answer - difficult. The parser is still too integrated with 
the run time code. As something part of my povr branch it's not the most 
unattractive idea because it tangles me in two different parser 
implementations.

Aside: I've thought about hacking versions of POV-Ray in a way where 
they could be run as 'parse to some intermediate form and stop' 
utilities. And that thought reminds me I want to implement an actual 
#stop after parse directive. I use #error, but it's an ugly way to stop 
after the parsing stage.

Anyway, thanks for the ideas! As with the ini and options setting 
approaches, I'm still uncertain where the povr code will go.

> 
> have only spent a few minutes looking over the attached, seem ok (bar copy/paste
> typos 'str_var' in 'forkversion.inc'.)

Thanks. I believe that fixed.

And apologies. I must not of finished the editing of forkversion.inc (or 
somehow didn't do a last save...) I picked up a number of other mistakes 
'I thought' I'd fixed.

Bill P.

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William F Pokorny <ano### [at] anonymousorg> wrote:
> On 2/17/22 02:39, jr wrote:
> > chain-loading via 'file_exists()' is nice + "clean" (imo).
> >
>
> I'm not completely sure I'm following what you mean by chain-loading?

do file_exists (filename)
if yes, run/include that file.
In THAT file is _another_ file_exists (filename)... and so on

daisy-chain everything together until you hit a dead-end.



> Aside: I've thought about hacking versions of POV-Ray in a way where
> they could be run as 'parse to some intermediate form and stop'
> utilities. And that thought reminds me I want to implement an actual
> #stop after parse directive. I use #error, but it's an ugly way to stop
> after the parsing stage.

Yes.
More useful would be to have that as a "function" that returns some sort of
state variable, visible to the OS/shell

I've also thought about a mechanism to "stop" and then _reparse_ the SDL file,
such that certain things could be scanned, written to file, or otherwise do a
pre-parse-and-render setup.  Maybe something like: #reparse 3
POV-Ray would parse until it hit that, decrement a counter, etc, until it read
through that directive at counter = 0.

I suppose we have workarounds for stuff like this.

I've also wondered about write-protecting files in some way to make editing them
a conscious and fully purposeful action.   Like locking the cells in a
spreadsheet so that critical, complicated formulas don't get edited by someone
trying to "improve" things.  ;)

Silly idea:   certain image formats have header sections where you can embed
virtually anything.   Would it be possible to have POV-Ray store scene files in
an image file format, with the SDL embedded in the header?  Not sure where I was
going with this a second ago - but just thinking about such a thing might spark
some new ideas about structuring scene, includes, etc.

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William F Pokorny <ano### [at] anonymousorg> wrote:
> On 2/17/22 02:39, jr wrote:
> > chain-loading via 'file_exists()' is nice + "clean" (imo).
> >
>
> I'm not completely sure I'm following what you mean by chain-loading?

as BE says.  what I tried to say is something like the mechanism is nice/clean
because it all is/can be transparent to the user (as your code snippet
demonstrates).


> > > Thinking
> ...
> It would probably be TCL if I do get around to trying something radical.

please do!  ;-)


> I have a lot of that going today - as you know - but the implementation
> writes SDL. In other words, it still leans on the current SDL parsers.

I guess that a C(++) extension for Tcl, to drive the VM from Tcl, would do it
:-), access through some "specialising" packages/modules perhaps.


> > out of interest, how difficult would it be to have two separate parsers?  one
> > for pre 3.7/8 compatibility, one for newer style.  (I'm guessing that the
> > executable would not be all that much larger, and separation might bring other
> > benefits)
>
> My up front answer - difficult. The parser is still too integrated with
> the run time code. As something part of my povr branch it's not the most
> unattractive idea because it tangles me in two different parser
> implementations.

ah, naively I'd thought that the existing CLI/ini 'version' could be (ab)used,
ie if not given start with forked parser, if any file read needs <3.8 stop/error
tell user either needs option switch (to start with the "compatible") or edit
offending file.


> Aside: I've thought about hacking versions of POV-Ray in a way where
> they could be run as 'parse to some intermediate form and stop'
> utilities. And that thought reminds me I want to implement an actual
> #stop after parse directive. I use #error, but it's an ugly way to stop
> after the parsing stage.

agree with BE, being able to return a status from a scene would be neat,
particularly if it's available for 'post_frame_command's.

also re his "silly idea", SDL (and or pre-parsed VM calls) storage -- how about
DB (sqlite) storage?


> Anyway, thanks for the ideas! As with the ini and options setting
> approaches, I'm still uncertain where the povr code will go.

:-)  you'll have to tell me when to stop.


regards, jr.

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hi,

"Bald Eagle" <cre### [at] netscapenet> wrote:
> ...
> Silly idea:   certain image formats have header sections where you can embed
> virtually anything.   Would it be possible to have POV-Ray store scene files in
> an image file format, with the SDL embedded in the header?  Not sure where I was
> going with this a second ago - but just thinking about such a thing might spark
> some new ideas about structuring scene, includes, etc.

look at attached with:

  $ hexdump -C hu_8.png | less

that what you mean?  ;-)

anyway, long story short, you can do in Tcl, for .png files.  install the
'Tcllib' package, then check out the man page (section n on my box) for 'png'.


regards, jr.

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Attachments:
Download 'hu_8.png' (17 KB)

Preview of image 'hu_8.png'

"jr" <cre### [at] gmailcom> wrote:
> hi,
>
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > ...
> > Silly idea:   certain image formats have header sections where you can embed
> > virtually anything.   Would it be possible to have POV-Ray store scene files in
> > an image file format, with the SDL embedded in the header?  Not sure where I was
> > going with this a second ago - but just thinking about such a thing might spark
> > some new ideas about structuring scene, includes, etc.
>
> look at attached with:
>
>   $ hexdump -C hu_8.png | less

Well, not exactly.   I think I wrote that on my way out to work, so it was just
a short brain-dump.

What I was actually thinking was that POV-Ray could use an image format as the
actual file format for storing the SDL text, and the editor could extract it
from that, display it, allow for editing, and re-save into the image file
wrapper.

Why do this:
I guess the idea was that since POV-Ray already has the ability to
parse/interpret image file formats already, it might be possible to somehow
embed a series of text files into the image header - like includes, etc and use
it kind of like a zip file.

Also, then we could have the image and the code that generated it all in one
place, so they aren't separated and lost/confused.

It might also be possible to implement security by obscurity, to protect certain
parts of code that an author might not want users casually messing with.  If you
really wanted to edit that code, you'd have to work for it, rather than just
"Ooops!  I broke it!"

But binary copy, hexdump, Tcp, and other tools might provide a sort of
functional work-around / proof of concept to see how a suite of files could
potentially be used ....

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