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[ruby-dev:16994] Adding once.rb to the standard library

  Sakuro Ozawa have proposed to add once.rb and func.rb to the standard
  library. These scripts are written by Tadayoshi Funaba.
  once.rb is useful to define some methods to be evaluated only once,
  and func.rb is to define mathematical functions. In a sense, those
  are useful to define some methods each of which returns cached value.
  Matz agreed with the idea of once.rb and func.rb, however he hesitated
  to add those libraries because of its untrivial/tricky implementation.
  (*) http://www.funaba.org/ruby.html#once
-- 
Takaaki Tateishi <ttate / kt.jaist.ac.jp>