float code, commented

floats.rb

class Float                             # because we are re-opening class float, anywhere we refer to self in
  def pretty_s                          # this method will be the floating point number we call "pretty_s" on.
    num = "%.12g" % self                # num is a string representation of self with 12 decimal places
    num.sub!(/\.(.*?)0+$/,".$1")        # remove any trailing zeroes
    # might be like 2. at this point    # if we had all zeroes, there would be nothing after the decimal point
    num = num[0..-2] if num[-1] == '.'  # thus, let's remove the decimal point in that case
    num                                 # and return our string
  end
end
p 1.1-0.9 # >> 0.20000000000000007      # floating point yuckiness means that we get this number instead of 0.2
p (1.1-0.9).pretty_s # >> "0.2"         # our pretty_s method solves that problem
p 2.0.pretty_s # >> "2"                 # here is what happens when there are only zeroes after the decimal