class Rcov::FileStatistics

def prev_expr_continued?(lineno)
  return false if lineno <= 0
  return false if lineno >= @lines.size
  found = false
  if @multiline_string_start[lineno] && 
    @multiline_string_start[lineno] < lineno
    return true
  end
  # find index of previous code line
  idx = (lineno-1).downto(0) do |i|
    if @heredoc_start[i]
      found = true
      break @heredoc_start[i] 
    end
    next unless is_code? i
    found = true
    break i
  end
  return false unless found
  #TODO: write a comprehensive list
  if is_code?(lineno) && /^\s*((\)|\]|\})\s*)+(?:#.*)?$/.match(@lines[lineno])
    return true
  end
  #FIXME: / matches regexps too
  # the following regexp tries to reject #{interpolation}
  r = /(,|\.|\+|-|\*|\/|<|>|%|&&|\|\||<<|\(|\[|\{|=|and|or|\\)\s*(?:#(?![{$@]).*)?$/.match @lines[idx]
  # try to see if a multi-line expression with opening, closing delimiters
  # started on that line
  [%w!( )!].each do |opening_str, closing_str| 
    # conservative: only consider nesting levels opened in that line, not
    # previous ones too.
    # next regexp considers interpolation too
    line = @lines[idx].gsub(/#(?![{$@]).*$/, "")
    opened = line.scan(/#{Regexp.escape(opening_str)}/).size
    closed = line.scan(/#{Regexp.escape(closing_str)}/).size
    return true if opened - closed > 0
  end
  if /(do|\{)\s*\|[^|]*\|\s*(?:#.*)?$/.match @lines[idx]
    return false
  end
  r
end