[NTG-context] Why does this example from the MetaFun manual not work?

[Taco Hoekwater]

Hi,

Using multiple (text <x>) arguments in macros doesn’t work, you would 
need to convert all but the last argument into (expr <x>) somehow.

That means that you probably cannot do a call like the one below at all.
(I, at least, do not see how you could convert one of those transparent 
colours into an expr <x> argument)

> 
> SampleText ("Much Of This", transparent(1, .5, red  ) , transparent(1, .5, green  )) ;

The situation may get even trickier because withtransparency() and
transparent() both use a  (text <x>) argument internally as well,
and I am not quite sure why.

At this point, I think you may need Hans for advice, sorry.

Taco