class Sass::Script::Parser

def interpolation(first = concat)
  e = first
  while interp = try_tok(:begin_interpolation)
    wb = @lexer.whitespace?(interp)
    line = @lexer.line
    mid = parse_interpolated
    wa = @lexer.whitespace?
    e = Script::Interpolation.new(e, mid, concat, wb, wa)
    e.line = line
  end
  e
end