I wish there was a widely available, widely known
general purpose
programming language which had a "number with precision" type, which
would Do The Right Thing when doing things like multiplying values
together - ie, decreasing the precision - and would let you specify a
required minimum precision for results or function parameters, with
exceptions being thrown if those can't be achieved. It would be nice to
be able to automate away the problem of "measure with a micrometer, mark
with chalk, cut with an axe".
Some years ago, at the HPCC conference (I think it was in 2007), Hugh
Steers presents a piece of software he'd written where you could specift
the precieon you wanted in the answer and which would then use better
approximations as necesssty until that precision had been reached.
I won't publish hs e-mail address on this list, but if you are interested
i can put you in touch with him.
-tony