# File lib/rcodetools/completion.rb, line 118
  def current_phrase(expr)
    paren_level = 0
    start = 0
    (expr.length-1).downto(0) do |i|
      c = expr[i,1]
      if c =~ /[\)\}\]]/
        paren_level += 1
        next
      end
      if paren_level > 0
        next if c =~ /[, ]/
      else
        break (start = i+1) if c =~ /[ ,\(\{\[]/
      end
      if c =~ /[\(\{\[]/
        paren_level -= 1
        break (start = i+1) if paren_level < 0
      end
    end
    expr[start..-1]
  end