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Still discussing <http://www.geocities.com/partsref/bfcspec.txt>.
Here's another syntactical approach to BFC. Like it, hate it, let us know what
you think.
Have a single 0 BFC statement, which allows specifications of various
options/settings. Something like:
0 BFC ( CERTIFY | NOCERTIFY | CLIP | NOCLIP | CW | CCW | NOWIND | INVERTNEXT )+
The + symbol indicates 1 or more occurrences of the preceeding group.
this could be written as:
0 BFC [CERTIFY | NOCERTIFY] [CLIP | NOCLIP] [CW | CCW | NOWIND] [INVERTNEXT]
... with the understanding that options could be specified in any order.
CERTIFY = the file is compliant
NOCERTIFY = the file is not compliant
CLIP = enable clipping
NOCLIP = disable clipping
CW = polygon winding is clockwise
CCW = polygon winding is anti-clockwise
NOWIND = polygon winding is variable
INVERTNEXT = the next command is a subfile reference, and it is inverted.
Only one option of each group would be allowed on a single statement. So CLIP
and NOCLIP couldn't be both specified on the same BFC line.
Any use of the 0 BFC command would indicate that the file is certified, except
for 0 BFC NOCERTIFY. So, strictly speaking, CERTIFY is redundant. Placing a 0
BFC CLIP or 0 BFC CW at the start of a file would be sufficient to certify that
file.
This approach has a couple of advantages:
- slightly simplify/streamline parsing, because only one meta-command is used.
- Allow us to get past the issue of "what statement should be used to mark
compliant files".
Steve
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Steve:
> Still discussing <http://www.geocities.com/partsref/bfcspec.txt>.
>
> Here's another syntactical approach to BFC. Like it, hate
> it, let us know what you think.
[...]
It is definitely a useable option. How will the
specification document look then? If it is easier to read
that way, then you have one proponent for that solution.
Play well,
Jacob
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-- E-mail: sparre@cats.nbi.dk --
-- Web...: <URL:http://www.ldraw.org/FAQ/> --
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In lugnet.cad.dev, Jacob Sparre Andersen wrote:
> Steve:
>
> > Still discussing <http://www.geocities.com/partsref/bfcspec.txt>.
> >
> > Here's another syntactical approach to BFC. Like it, hate
> > it, let us know what you think.
>
> [...]
>
> It is definitely a useable option. How will the
> specification document look then? If it is easier to read
> that way, then you have one proponent for that solution.
There are two possibilities for updating the document with this approach:
1. Just change the syntax expressions, and modify any syntax-specific
references. This would be the low-impact approach, with only cosmetic changes.
2. Rework the document. Add a new section which discusses the functional
requirements (must be able to turn clipping on and off, set the winding, and
invert subfiles), and change the existing "Language Extensions" section to
specify how the single 0 BFC statement implements the requirements.
I'll try doing #2 this weekend.
Steve
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In lugnet.cad.dev, Steve Bliss wrote:
Still discussing <http://www.geocities.com/partsref/bfcspec.txt>.
I posted a new version, with the short-form syntax, to
<http://www.geocities.com/partsref/bfcspecv4.txt>
Comments?
Steve
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Steve:
> Still discussing <http://www.geocities.com/partsref/bfcspec.txt>.
>
> I posted a new version, with the short-form syntax, to
> <http://www.geocities.com/partsref/bfcspecv4.txt>
>
> Comments?
My comments/changes will be preceded by a "J".
[...]
Subfile. A DAT file referenced from another file, via a linetype 1 command.
Or any file which is lower in the file-reference tree than the current file.
J Or any file which is the subfile of the current file (or thus of any of its
J subfiles).
J
1 Subpart. A DAT file which is only a portion of a complete element. Does
[...]
4 CERTIFY
4 Certified = (Command.Option = "BFC")
4 CLIPPING
4 LocalClip = (Command.Option = "ON")
J What does this "Command.Option" stuff mean?
[...]
There may be more comments later, but I have to go now.
Play well,
Jacob
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-- E-mail: sparre@cats.nbi.dk --
-- Web...: <URL:http://www.ldraw.org/FAQ/> --
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In lugnet.cad.dev, Jacob Sparre Andersen wrote:
> Steve:
>
> > Still discussing <http://www.geocities.com/partsref/bfcspec.txt>.
> >
> > I posted a new version, with the short-form syntax, to
> > <http://www.geocities.com/partsref/bfcspecv4.txt>
> >
> > Comments?
>
> My comments/changes will be preceded by a "J".
>
> [...]
> Subfile. A DAT file referenced from another file, via a linetype 1 command.
> Or any file which is lower in the file-reference tree than the current file.
>
> J Or any file which is the subfile of the current file (or thus of any of its
> J subfiles).
Er, OK. I'll put that in, but it seems redundant.
> 1 Subpart. A DAT file which is only a portion of a complete element. Does
> [...]
> 4 CERTIFY
> 4 Certified = (Command.Option = "BFC")
> 4 CLIPPING
> 4 LocalClip = (Command.Option = "ON")
>
> J What does this "Command.Option" stuff mean?
It means that I stuffed in the pseudo-code without rewriting the syntax-specific
sections. :(
Steve
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