class RubyLex

def check_code_syntax(code)
  lvars_code = RubyLex.generate_local_variables_assign_code(@context.local_variables)
  code = "#{lvars_code}\n#{code}"
  begin # check if parser error are available
    verbose, $VERBOSE = $VERBOSE, nil
    case RUBY_ENGINE
    when 'ruby'
      self.class.compile_with_errors_suppressed(code) do |inner_code, line_no|
        RubyVM::InstructionSequence.compile(inner_code, nil, nil, line_no)
      end
    when 'jruby'
      JRuby.compile_ir(code)
    else
      catch(:valid) do
        eval("BEGIN { throw :valid, true }\n#{code}")
        false
      end
    end
  rescue EncodingError
    # This is for a hash with invalid encoding symbol, {"\xAE": 1}
    :unrecoverable_error
  rescue SyntaxError => e
    case e.message
    when /unterminated (?:string|regexp) meets end of file/
      # "unterminated regexp meets end of file"
      #
      #   example:
      #     /
      #
      # "unterminated string meets end of file"
      #
      #   example:
      #     '
      return :recoverable_error
    when /syntax error, unexpected end-of-input/
      # "syntax error, unexpected end-of-input, expecting keyword_end"
      #
      #   example:
      #     if true
      #       hoge
      #       if false
      #         fuga
      #       end
      return :recoverable_error
    when /syntax error, unexpected keyword_end/
      # "syntax error, unexpected keyword_end"
      #
      #   example:
      #     if (
      #     end
      #
      #   example:
      #     end
      return :unrecoverable_error
    when /syntax error, unexpected '\.'/
      # "syntax error, unexpected '.'"
      #
      #   example:
      #     .
      return :unrecoverable_error
    when /unexpected tREGEXP_BEG/
      # "syntax error, unexpected tREGEXP_BEG, expecting keyword_do or '{' or '('"
      #
      #   example:
      #     method / f /
      return :unrecoverable_error
    else
      return :other_error
    end
  ensure
    $VERBOSE = verbose
  end
  :valid
end