visual indentation

[Hans Nowak]

Hilbert wrote:
> Hello,
> 
> I'm using python to output RIB streams for Renderman.
> The RIB stream is a bunch of statements which describes 
> a 3d image. The Rib standard allows for blocks which we
> usually indent for better visualization for example:
> 
> WorldBegin 
>     Color [1 1 1]
>     Surface "constant"
>     Sphere(1.0, -1.0, 1.0, 360)
> WorldEnd
> 
> I'm using CGKit in python which has a Renderman binding, 
> so to output the same RIB I'd write:
> 
> RiWorldBegin()
>     RiColor(1.0,1.0,1.0)
>     RiSurface('constant')
>     RiSphere(1.0,-1.0,1.0,360)
> RiWorldEnd()
> 
> But I get an error, because python interprets my indentation
> as a block in the python code. So the only way to write this 
> is without the indentation:
> 
> RiWorldBegin()
> RiColor(1.0,1.0,1.0)
> RiSurface('constant')
> RiSphere(1.0,-1.0,1.0,360)
> RiWorldEnd()
> 
> But this is a lot harder to read.
> 
> Is there any way to use such "visual" indentation in python?

I can think of various ugly solutions, none of them very satisfying...

First, you can fake an indented block, e.g. like this:

RiWorldBegin()
if 1:
     RiColor(1.0, 1.0, 1.0)
     # etc...
RiWorldEnd()

Or you can put the function calls in a dummy list/tuple:

RiWorldBegin()
[
     RiColor(1.0, 1.0, 1.0),
     RiSurface('constant'),
     RiSphere(1.0,-1.0,1.0,360),
]
RiWorldEnd()

Or you can put some dummy statements in front...

RiWorldBegin()
();    RiColor(1.0, 1.0, 1.0)
();    RiSurface('constant')
();    RiSphere(1.0,-1.0,1.0,360)
RiWorldEnd()

I warned you they were ugly... :-)

Maybe the best solution would be judicious use of comments, e.g.

RiWorldBegin()
#
RiColor(1.0, 1.0, 1.0)
RiSurface('constant')
RiSphere(1.0,-1.0,1.0,360)
#
RiWorldEnd()

This doesn't give you indentation, but at least the statements in the "block" 
stand out more.

But maybe somebody else has a better solution...?

-- 
Hans (hans at zephyrfalcon.org)
http://zephyrfalcon.org/