a long time ago, I was gonna try doing this for matlab. This looks easier. :S

sigdigs.py

"""
A sketch for an idea I've had since forever regarding significance arithmetic.
http://en.wikipedia.org/wiki/Significance_arithmetic
Yeah, that annoying shit you did in chemistry class and hoped never to see again.
With this, maybe you can?
"""

class significants(number):
    # note: not actually sure how to do some of these things
    def __init__:

        # TODO: Be able to specify number of significant figures optionally

        self.number=number
        # find (sf, 10^x)
        # 1) Find decimal place, if any.
        if !decimal_place:
            # find first_n_nonzero
            # find zeros_after
            # self.sf=first_n_nonzero
        else:
            # find num_dec_digits
            # find length_of_number
            #self.sf=length_of_number


    # note: Use banker's rounding
    def __mult__(self,other):
        sf_out=min(self.sf,other.sf)
        
    def __add__(self,other):
        if self.sd-self.ten2the > other.sd-other.ten2the:
            sf_out = self.sd
        else:  
            sf_out = other.sd

if __name__ == "__main__":
    #tests