From: dave.burt@...
Date: 2005-10-11T13:26:52+09:00
Subject: RCR 320: Extend Rational to play nice with floats

Hi,

It's been a while since I extended Rational to convert nicely from
floats and strings (among other enhancements), and showed that code to
ruby-talk.

Now it's an RCR: http://www.rcrchive.net/rcr/show/320

  # Rational() is backwards-compatible
  Rational(1)  #=> Rational(1, 1)
  Rational(1, 2)  #=> Rational(1, 2)
  # ... but also accepts floats
  Rational(1.3)  #=> Rational(5854679515581645, 4503599627370496)
  # ... and strings
  Rational("1.3")  #=> Rational(13, 10)
  Rational("1.2e-3")  #=> Rational(-3, 2500)
  Rational("1/2")  #=> Rational(1, 2)
  Rational("1.5/2.3")  #=> Rational(15, 23)
  Rational("1.5", "2.3")  #=> Rational(15, 23)
  # Floats and strings have an explicit cast to_r method
  "1.5/2.3".to_r  #=> Rational(15, 23)
  -0.25.to_r  #=> Rational(-1, 4)
  # You can get fractions back from the floats:
  Rational(1.3).approximate  #=> Rational(13, 10)
  Rational(0.3333333333333).approximate  #=> Rational(1, 3)

Feedback's welcome on the RCR or here.

Cheers,
Dave