Meaningful parameters.

[Jim Kingdon]

> the pointer to the unit which receives the extracted material I call
> 'extractor', and when the id of the unit is needed, I've changed the
> name to 'extractor_ut' from 'u2' to disginguish the pointer from the
> unit type. Maybe 'extractor_u' would be better?

I've been using "uextractor" (don't remember if I saw that somewhere
or just made it up) but extractor_type or extractor_utype or any of
the ones don't horrify me.  Although I suppose it should be some
combination of "extractor" and "u".

Thanks for doing this work.

> I also changed 'unit3' used in the stack iteration to 'stack_unit',
> although 'stacked_unit" might be better.

I'd be tempted to call it "i" - the universal symbol for an iteration
variable.

> Thee is already some consistancy, unit pointers are almost always
> 'unit', but unit types are almost always 'u'.

Right, let's try to build on that except where it is clearly broken
(e.g. the infamous unit, unit2, unit3 case).