class Sass::Script::StringInterpolation

def to_sass(opts = {})
  # We can get rid of all of this when we remove the deprecated :equals context
  before_unquote, before_quote_char, before_str = parse_str(@before.to_sass(opts))
  after_unquote, after_quote_char, after_str = parse_str(@after.to_sass(opts))
  unquote = before_unquote || after_unquote ||
    (before_quote_char && !after_quote_char && !after_str.empty?) ||
    (!before_quote_char && after_quote_char && !before_str.empty?)
  quote_char =
    if before_quote_char && after_quote_char && before_quote_char != after_quote_char
      before_str.gsub!("\\'", "'")
      before_str.gsub!('"', "\\\"")
      after_str.gsub!("\\'", "'")
      after_str.gsub!('"', "\\\"")
      '"'
    else
      before_quote_char || after_quote_char
    end
  res = ""
  res << 'unquote(' if unquote
  res << quote_char if quote_char
  res << before_str
  res << '#{' << @mid.to_sass(opts) << '}'
  res << after_str
  res << quote_char if quote_char
  res << ')' if unquote
  res
end