class Sass::Script::Lexer

def op
  prev_chr = @scanner.string[@scanner.pos - 1].chr
  return unless op = @scanner.scan(REGULAR_EXPRESSIONS[:op])
  if @prev && op == '-' && prev_chr !~ /\s/ &&
      [:bool, :ident, :const].include?(@prev.type)
    warn(<<END)
ATION WARNING:
e #{@line}, character #{last_match_position}#{" of '#{@filename}'" if @filename}
 be allowed as part of variable names in version 2.4.
 add whitespace to separate it from the previous token.
  end
  [OPERATORS[op]]
end