[Dxfreader-info] BLOCKS refactor and BBDXFTuple rename

[Allan D. <all...@gm...>]

Mike,

I started to tackle the BLOCKS logic/parsing/etc. A BLOCK definition  
in the BLOCKS section is a collection of regular DXF entities that are  
defined exactly the same in the BLOCKS section as they are in the main  
ENTITIES section. The one difference is that a BLOCK definition has  
some meta-data attached to it -- a name, some flags, an XYZ origin  
point for example. Entities inside the block have their XYZ  
coordinates set relative to this block origin point.

Both a BLOCK definition and the ENTITIES section contain a collection  
of entities. In order to structure things cleanly I think we need to  
refactor the entities array and accessor methods out of the BBDXFModel  
object and create a new BBDXFEntitiesCollection object to hold them  
instead.

A BBDXFModel can then contain one of these entity collections to  
represent the main entities collection and a BBDXFBLock can also  
contain one of these entity collections to contain all the entities  
associated with that block.

The BBDXFModel can also of course contain all the other model data  
defined in the drawing (the header dictionary you created, for  
example) and the BBDXFBlock object can contain all the block meta-data.


The other thing I wanted to suggest is that your BBDXFTuple object be  
renamed to DXFTwople. Since it's just an internal private object,  
there's no need to put the BB on there since it will not be reference  
or reused publicly and there's no chance for any confusion with anyone  
else's Tuple (or Twople) object. Second since the object refers to a  
pair of two lines inside the DXF file, I think using the word "two" in  
there would make things a bit clearer. Once upon a time I did a lot of  
theater and there was a "twofer" plug that allowed you to put two  
theatrical lights into one plug. The "two" helps explain things --  
your "tu" confused me on the first pass through. Are you OK with  
renaming that? I propose "DXFTwople."


The next big topic here is who does what and how do we coordinate?  
Let's make a plan for working in parallel and then I'll dive in to  
these changes. I also want to hear your thoughts on these changes.

Thanks.

-Allan