Reals is a lightweight Python library for arbitrary precision arithmetic. It
allows you to compute approximations to an arbitrary degree of precision, and,
contrary to most other libraries, guarantees that all digits it displays are
correct. It works by using interval arithmetic and continued fractions. The
bulk of this code is based on Bill Gosper's notes on continued fractions in
which he presents algorithms for doing arithmetic on continued fractions.

The reals library is characterized by:

  * Correctness; the reals library uses interval arithmetic to ensure that all
    the digits are correct.
  * Calculations are done in a streaming way; the result of previous
    calculations can be re-used.
  * Uses no external libraries.
  * Focus on usability.