What should an $(add) function look like?

[Tim Murphy]

Hi,

I'm implementing some new GNU make functions as loadable modules and I just
wondered if anyone had thoughts about how it would be best to implement
some of them.

The one I'm looking at now is meant to be a way to add integers.

My major use would be to e.g. implement a counter so I'm mostly thinking of
being able to do COUNTER:=$(add $(COUNTER),1)

i.e. $(add x,y).   One might also implement a range function recursively
with this e.g. $(call range,1,10) returning "1 2 3 4 5 6 7 8 9"

I'm thinking that the numbers could be integers so $(add x,-1) would
decrement.

As I was implementing this, however, I thought: why not add a list of
numbers?

e.g.
$(add 1 2  3 -1 1)

This might turn out to be much more generally useful.   e.g. adding a list
of file sizes together or something similar.  Is this a good idea?

I also think that some numeric comparison functions might be handy e.g.
$(gt x,y) and $(lt x,y) plus the other obvious variations. Is there
anything else worth putting in?

Regards,

Tim