TEXINPUTS: how to handle "extensions"

[Sebastian Rahtz]

Thomas Esser writes:
 > For the next teTeX release, I want to build a special "french" format
 > with ML extensions. The french package needs some special files for the
 > initex run that I want to use.
moral, dont do build frtex...

 > Using this approach we would
 >   - get just one more top-level directory
 >   - be able to add files visible only for some (and not for all) formats

i think its an abuse, to be honest, and the road to ruin. 

conceivably 

 $TDS/mltex/french/base

? doesnt mltex add a new primitive?

s