ReplaceRepeated by Ruby

gistfile1.rb

require 'pattern-match'

def replace_repeated(val, &block)
  ret = match(val, &block)
  if ret == val
    ret
  else
    replace_repeated(ret, &block)
  end
rescue PatternMatch::NoMatchingPatternError
  val
end

replace_repeated([1, 2, 4, 4, 3, 3, 4, 0, 0]) do
  with(_[*a, x, x, *b]) { [*a, x, *b] }
end #=> [1, 2, 4, 3, 4, 0]

# Mathematica (http://nyaruru.hatenablog.com/entry/20090311/p1)
#   {1, 2, 4, 4, 3, 3, 4, 0, 0} //. {a___, x_, x_, b___} -> {a, x, b}
#   (* 結果: {1, 2, 4, 3, 4, 0} *)