class Haml::RubyExpression

def self.string_literal?(code)
  return false if syntax_error?(code)
  type, instructions = Ripper.sexp(code)
  return false if type != :program
  return false if instructions.size > 1
  type, _ = instructions.first
  type == :string_literal
end

def self.syntax_error?(code)
  self.new(code).parse
  false
rescue ParseError
  true
end

def on_parse_error(*)
  raise ParseError
end