[Bf-python] [Bf-committers] [Bf-blender-cvs] SVN commit: /data/svn/bf-blender [10922] branches/pyapi_devel/source/ blender/python/api2_2x: Camera, Scene, Object - removed get/set' s from the API (getName, setName) - just use .name

[Stephen Swaney]

On Thu, Jun 14, 2007 at 04:26:46PM +1000, Campbell Barton wrote:
> I had a search, and nothing specific to this came up such as - "Should 
> We have Layers and layers" - but I think it needs to be discussed.

The name Layers is a holdover from olden times before we standardised
on an attribute naming convention.  In a nutshell, layers is preferred,
Layers is old, legacy cruft that can and should fade away.


> If layers as lists are supported they should all share code and possibly 
> even have a reference wo the original data so one could do 
> ob.layers.append(20) or ob.layers.remove(1)
> 
> but personally I find lists are a bad way to represent layers
> 
> for instance, if you want to remove a layer you have to check its in the 
> list operate on the list and then re-assign it.
> 
> if 1 in ob.layers:
>    layers = ob.layers
>    layers.remove(1)
>    ob.layers = layers
> 

I agree that a list is an unsuitable data structure to represent layers.
Something that works like ob.layers.remove(1) or ob.layers.add(1) is
much more straight forward.

Being able to assign like ob.layers = old-layers is useful too.
Same with supporting the iterator protocol.

> whereas..
> 
> ob.layers &= ~1 # does the same thing
> 
> looping on layers is nicer with ob.layers (list) but not bad with a bitmask
> 
> for i in xrange(20):
>     if ob.Layers & 1<<i:
>         ....
> I think we could have docs with snippets like this showing scripters how 
> they can do layer operations with bitmasks.
> 
> when using 1<<4 syntax its not that hard to do.

The bitmask syntax is fine for anyone who understands C programming.
However, one of our target audiences is the 'naive scripter or artist
who needs to create simple utilities or macros.  For them, ob.layers &= ~1
is just a little to cryptic.

I can see supporting both styles, but to solely use the bitmask syntax is
ungood.


-- 
Stephen Swaney			
sswaney at centurytel.net