text: r"""
  Sage's IPython Modifications
  
  This module contains all of Sage's customizations to the IPython
  interpreter.  These changes consist of the following major components:
  
    - :class:`SageTerminalApp`
    - :class:`SageInteractiveShell`
    - :class:`SageTerminalInteractiveShell`
    - :func:`interface_shell_embed`
  
  SageTerminalApp
  ---------------
  
  This is the main application object.  It is used by the
  ``$SAGE_LOCAL/bin/sage-ipython`` script to start the Sage
  command-line.  It's primary purpose is to
  
    - Initialize the :class:`SageTerminalInteractiveShell`.
  
    - Provide default configuration options for the shell, and its
      subcomponents.  These work with (and can be overridden by)
      IPython's configuration system.
  
    - Load the Sage ipython extension (which does things like preparsing,
      add magics, etc.).
  
    - Provide a custom :class:`SageCrashHandler` to give the user
      instructions on how to report the crash to the Sage support
      mailing list.
  
  SageInteractiveShell
  --------------------
  
  The :class:`SageInteractiveShell` object is the object responsible for
  accepting input from the user and evaluating it.  From the command-line,
  this object can be retrieved by running::
  
      sage: shell = get_ipython()   # not tested
  
  Any input is preprocessed and evaluated inside the ``shell.run_cell``
  method. If the command line processing does not do what you want it to
  do, you can step through it in the debugger::
  
      sage: %debug shell.run_cell('?')        # not tested
  
  The :class:`SageInteractiveShell` provides the following
  customizations:
  
    - Modify the libraries before calling system commands. See
      :meth:`~SageInteractiveShell.system_raw`.
  
  SageTerminalInteractiveShell
  ----------------------------
  
  The :class:`SageTerminalInteractiveShell` is a close relative of
  :class:`SageInteractiveShell` that is specialized for running in a
  terminal. In particular, running commands like ``!ls`` will directly
  write to stdout. Technically, the ``system`` attribute will point to
  ``system_raw`` instead of ``system_piped``.
  
  Interface Shell
  ---------------
  
  The function :func:`interface_shell_embed` takes a
  :class:`~sage.interfaces.interface.Interface` object and returns an
  embeddable IPython shell which can be used to directly interact with
  that shell.  The bulk of this functionality is provided through
  :class:`InterfaceShellTransformer`.
  
  TESTS:
  
  Check that Cython source code appears in tracebacks::
  
      sage: from sage.repl.interpreter import get_test_shell
      sage: shell = get_test_shell()
      sage: print("dummy line"); shell.run_cell('1/0') # see #25320 for the reason of the `...` and the dummy line in this test
      dummy line
      ...
      ZeroDivisionError...Traceback (most recent call last)
      <ipython-input-...> in <module>...
      ----> 1 Integer(1)/Integer(0)
      .../sage/rings/integer.pyx in sage.rings.integer.Integer...div...
      ...
      -> ...                  raise ZeroDivisionError("rational division by zero")
         ....:            x = <Rational> Rational.__new__(Rational)
         ....:            mpq_div_zz(x.value, ....value, (<Integer>right).value)
      <BLANKLINE>
      ZeroDivisionError: rational division by zero
      sage: shell.quit()
  
  Test prompt transformer::
  
      sage: from sage.repl.interpreter import SagePromptTransformer
      sage: spt = SagePromptTransformer
      sage: spt(["sage: 2 + 2"])
      ['2 + 2']
      sage: spt([''])
      ['']
      sage: spt(["....: 2+2"])
      ['2+2']
  
  This should strip multiple prompts: see :trac:`16297`::
  
      sage: spt(["sage:   sage: 2+2"])
      ['2+2']
      sage: spt(["   sage: ....: 2+2"])
      ['2+2']
  
  The prompt contains a trailing space. Extra spaces between the
  last prompt and the remainder should not be stripped::
  
      sage: spt(["   sage: ....:    2+2"])
      ['   2+2']
  
  We test that the input transformer is enabled on the Sage command
  line::
  
      sage: from sage.repl.interpreter import get_test_shell
      sage: shell = get_test_shell()
      sage: shell.run_cell('sage: a = 123')              # single line
      sage: shell.run_cell('sage: a = [\n... 123]')      # old-style multi-line
      sage: shell.run_cell('sage: a = [\n....: 123]')    # new-style multi-line
  
  We test that :trac:`16196` is resolved::
  
      sage: shell.run_cell('    sage: 1+1')
      2
      sage: shell.quit()
  """
  
  # ****************************************************************************
  #       Copyright (C) 2004-2012 William Stein <wstein@gmail.com>
  #
  # This program is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 2 of the License, or
  # (at your option) any later version.
  #                  https://www.gnu.org/licenses/
  # ****************************************************************************
  import re
  from traitlets import Bool, Type
  
  from sage.repl.preparse import preparse, containing_block
  from sage.repl.prompts import InterfacePrompts
  from sage.repl.configuration import sage_ipython_config, SAGE_EXTENSION
  
  from IPython.core.interactiveshell import InteractiveShell
  from IPython.terminal.interactiveshell import TerminalInteractiveShell
  from IPython.core.inputtransformer2 import PromptStripper
  from IPython.core.prefilter import PrefilterTransformer
  from IPython.terminal.embed import InteractiveShellEmbed
  from IPython.terminal.ipapp import TerminalIPythonApp, IPAppCrashHandler
  from IPython.core.crashhandler import CrashHandler
  
  
  def embedded():
      """
      Return True if Sage is being run from the notebook.
  
      EXAMPLES::
  
          sage: from sage.repl.interpreter import embedded
          sage: embedded()
          False
      """
      import sage.server.support
      return sage.server.support.EMBEDDED_MODE
  
  
  # TODO: This global variable _do_preparse should be associated with an
  # IPython InteractiveShell as opposed to a global variable in this
  # module.
  _do_preparse = True
  
  
  def preparser(on=True):
      """
      Turn on or off the Sage preparser.
  
      :keyword on: if True turn on preparsing; if False, turn it off.
      :type on: bool
  
      EXAMPLES::
  
          sage: 2/3
          2/3
          sage: preparser(False)
          sage: 2/3  # not tested since doctests are always preparsed
          0
          sage: preparser(True)
          sage: 2^3
          8
      """
      global _do_preparse
      _do_preparse = on is True
  
  
  ##############################
  # Sage[Terminal]InteractiveShell
  ##############################
  class SageShellOverride(object):
      """
      Mixin to override methods in IPython's [Terminal]InteractiveShell
      classes.
      """
  
      def show_usage(self):
          """
          Print the basic Sage usage.
  
          This method ends up being called when you enter ``?`` and
          nothing else on the command line.
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import get_test_shell
              sage: shell = get_test_shell()
              sage: shell.run_cell('?')
              Welcome to Sage ...
              sage: shell.quit()
          """
          from sage.misc.sagedoc import help
          help()
  
      def system_raw(self, cmd):
          """
          Run a system command.
  
          This is equivalent to the sage-native-execute shell script.
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import get_test_shell
              sage: shell = get_test_shell()
              sage: shell.system_raw('false')
              sage: shell.user_ns['_exit_code'] > 0
              True
              sage: shell.system_raw('true')
              sage: shell.user_ns['_exit_code']
              0
              sage: shell.system_raw('R --version')
              R version ...
              sage: shell.user_ns['_exit_code']
              0
              sage: shell.quit()
          """
          return super(SageShellOverride, self).system_raw(cmd)
  
  
  class SageNotebookInteractiveShell(SageShellOverride, InteractiveShell):
      """
      IPython Shell for the Sage IPython Notebook
  
      The doctests are not tested since they would change the current
      rich output backend away from the doctest rich output backend.
  
      EXAMPLES::
  
          sage: from sage.repl.interpreter import SageNotebookInteractiveShell
          sage: SageNotebookInteractiveShell()   # not tested
          <sage.repl.interpreter.SageNotebookInteractiveShell object at 0x...>
      """
  
      def init_display_formatter(self):
          """
          Switch to the Sage IPython notebook rich output backend
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import SageNotebookInteractiveShell
              sage: SageNotebookInteractiveShell().init_display_formatter()   # not tested
          """
          from sage.repl.rich_output.backend_ipython import BackendIPythonNotebook
          backend = BackendIPythonNotebook()
          backend.get_display_manager().switch_backend(backend, shell=self)
  
  
  class SageTerminalInteractiveShell(SageShellOverride, TerminalInteractiveShell):
      """
      IPython Shell for the Sage IPython Commandline Interface
  
      The doctests are not tested since they would change the current
      rich output backend away from the doctest rich output backend.
  
      EXAMPLES::
  
          sage: from sage.repl.interpreter import SageTerminalInteractiveShell
          sage: SageTerminalInteractiveShell()   # not tested
          <sage.repl.interpreter.SageNotebookInteractiveShell object at 0x...>
      """
  
      def init_display_formatter(self):
          """
          Switch to the Sage IPython commandline rich output backend
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import SageTerminalInteractiveShell
              sage: SageTerminalInteractiveShell().init_display_formatter()   # not tested
          """
          from sage.repl.rich_output.backend_ipython import BackendIPythonCommandline
          backend = BackendIPythonCommandline()
          backend.get_display_manager().switch_backend(backend, shell=self)
  
  
  class SageTestShell(SageShellOverride, TerminalInteractiveShell):
      """
      Test Shell
  
      Care must be taken in these doctests to quit the test shell in
      order to switch back the rich output display backend to the
      doctest backend.
  
      EXAMPLES::
  
          sage: from sage.repl.interpreter import get_test_shell
          sage: shell = get_test_shell();  shell
          <sage.repl.interpreter.SageTestShell object at 0x...>
          sage: shell.quit()
      """
  
      def init_display_formatter(self):
          """
          Switch to the Sage IPython commandline rich output backend
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import get_test_shell
              sage: shell = get_test_shell();  shell
              <sage.repl.interpreter.SageTestShell object at 0x...>
              sage: shell.quit()
              sage: shell.init_display_formatter()
              sage: shell.quit()
          """
          from sage.repl.rich_output.backend_ipython import BackendIPythonCommandline
          self._ipython_backend = backend = BackendIPythonCommandline()
          self._display_manager = backend.get_display_manager()
          self._doctest_backend = self._display_manager.switch_backend(backend, shell=self)
  
      def quit(self):
          """
          Quit the test shell.
  
          To make the test shell as realistic as possible, we switch to
          the
          :class:`~sage.repl.rich_output.backend_ipython.BackendIPythonCommandline`
          display backend. This method restores the previous display
          backend, which is the
          :class:`~sage.repl.rich_output.backend_doctest.BackendDoctest`
          during doctests.
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import get_test_shell
              sage: from sage.repl.rich_output import get_display_manager
              sage: get_display_manager()
              The Sage display manager using the doctest backend
  
              sage: shell = get_test_shell()
              sage: get_display_manager()
              The Sage display manager using the IPython command line backend
  
              sage: shell.quit()
              sage: get_display_manager()
              The Sage display manager using the doctest backend
          """
          self._display_manager.switch_backend(self._doctest_backend)
  
      def _restart(self):
          """
          Restart the test shell (after :meth:`quit`).
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import get_test_shell
              sage: shell = get_test_shell()
              sage: shell.quit()
              sage: shell._restart()
              sage: shell.quit()
              sage: from sage.repl.rich_output import get_display_manager
              sage: get_display_manager()
              The Sage display manager using the doctest backend
          """
          self._display_manager.switch_backend(self._ipython_backend, shell=self)
  
      def run_cell(self, *args, **kwds):
          """
          Run IPython cell
  
          Starting with IPython-3.0, this returns an success/failure
          information. Since it is more convenient for doctests, we
          ignore it.
  
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import get_test_shell
              sage: shell = get_test_shell()
              sage: rc = shell.run_cell('2^50')
              1125899906842624
              sage: rc is None
              True
              sage: shell.quit()
          """
          super(SageTestShell, self).run_cell(*args, **kwds)
  
  
  ###################################################################
  # Transformers used in the SageInputSplitter
  ###################################################################
  
  
  def SagePreparseTransformer(lines):
      r"""
      EXAMPLES::
  
          sage: from sage.repl.interpreter import SagePreparseTransformer
          sage: spt = SagePreparseTransformer
          sage: spt(['1+1r+2.3^2.3r\n'])
          ["Integer(1)+1+RealNumber('2.3')**2.3\n"]
          sage: preparser(False)
          sage: spt(['2.3^2\n'])
          ['2.3^2\n']
  
      TESTS:
  
      Check that syntax errors in the preparser do not crash IPython,
      see :trac:`14961`. ::
  
          sage: preparser(True)
          sage: bad_syntax = "R.<t> = QQ{]"
          sage: preparse(bad_syntax)
          Traceback (most recent call last):
          ...
          SyntaxError: Mismatched ']'
          sage: from sage.repl.interpreter import get_test_shell
          sage: shell = get_test_shell()
          sage: shell.run_cell(bad_syntax)
            File "<string>", line unknown
          SyntaxError: Mismatched ']'
          <BLANKLINE>
          sage: shell.quit()
  
      Make sure the quote state is carried over across subsequent lines in order
      to avoid interfering with multi-line strings, see :trac:`30417`. ::
  
          sage: SagePreparseTransformer(["'''\n", 'abc-1-2\n', "'''\n"])
          ["'''\n", 'abc-1-2\n', "'''\n"]
          sage: # instead of ["'''\n", 'abc-Integer(1)-Integer(2)\n', "'''\n"]
  
      .. NOTE::
  
          IPython may call this function more than once for the same input lines.
          So when debugging the preparser, print outs may be duplicated. If using
          IPython >= 7.17, try:
          ``sage.repl.interpreter.SagePreparseTransformer.has_side_effects = True``
  
      """
      if _do_preparse:
          # IPython ensures the input lines end with a newline, and it expects
          # the same of the output lines.
          lines = preparse(''.join(lines)).splitlines(keepends=True)
      return lines
  
  
  SagePromptTransformer = PromptStripper(prompt_re=re.compile(r'^(\s*(:?sage: |\.\.\.\.: ))+'))
  
  
  ###################
  # Interface shell #
  ###################
  
  class InterfaceShellTransformer(PrefilterTransformer):
      priority = 50
  
      def __init__(self, *args, **kwds):
          """
          Initialize this class.  All of the arguments get passed to
          :meth:`PrefilterTransformer.__init__`.
  
          .. attribute:: temporary_objects
  
             a list of hold onto interface objects and keep them from being
             garbage collected
  
          .. SEEALSO:: :func:`interface_shell_embed`
  
          TESTS::
  
              sage: from sage.repl.interpreter import interface_shell_embed
              sage: shell = interface_shell_embed(maxima)
              sage: ift = shell.prefilter_manager.transformers[0]
              sage: ift.temporary_objects
              set()
              sage: ift._sage_import_re.findall('sage(a) + maxima(b)')
              ['sage(', 'maxima(']
          """
          super(InterfaceShellTransformer, self).__init__(*args, **kwds)
          self.temporary_objects = set()
          self._sage_import_re = re.compile(r'(?:sage|%s)\('
                                            % self.shell.interface.name())
  
      def preparse_imports_from_sage(self, line):
          """
          Finds occurrences of strings such as ``sage(object)`` in
          *line*, converts ``object`` to :attr:`shell.interface`,
          and replaces those strings with their identifier in the new
          system.  This also works with strings such as
          ``maxima(object)`` if :attr:`shell.interface` is
          ``maxima``.
  
          :param line: the line to transform
          :type line: string
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import interface_shell_embed, InterfaceShellTransformer
              sage: shell = interface_shell_embed(maxima)
              sage: ift = InterfaceShellTransformer(shell=shell, config=shell.config, prefilter_manager=shell.prefilter_manager)
              sage: ift.shell.ex('a = 3')
              sage: ift.preparse_imports_from_sage('2 + sage(a)')
              '2 + sage0 '
              sage: maxima.eval('sage0')
              '3'
              sage: ift.preparse_imports_from_sage('2 + maxima(a)') # maxima calls set_seed on startup which is why 'sage0' will becomes 'sage4' and not just 'sage1'
              '2 +  sage4 '
              sage: ift.preparse_imports_from_sage('2 + gap(a)')
              '2 + gap(a)'
  
          Since :trac:`28439`, this also works with more complicated expressions
          containing nested parentheses::
  
              sage: shell = interface_shell_embed(gap)
              sage: shell.user_ns = locals()
              sage: ift = InterfaceShellTransformer(shell=shell, config=shell.config, prefilter_manager=shell.prefilter_manager)
              sage: line = '2 + sage((1+2)*gap(-(5-3)^2).sage()) - gap(1+(2-1))'
              sage: line = ift.preparse_imports_from_sage(line)
              sage: gap.eval(line)
              '-12'
          """
          new_line = []
          pos = 0
          while True:
              m = self._sage_import_re.search(line, pos)
              if not m:
                  new_line.append(line[pos:])
                  break
              expr_start, expr_end = containing_block(line, m.end() - 1,
                                                      delimiters=['()'])
              expr = preparse(line[expr_start + 1:expr_end - 1])
              result = self.shell.interface(eval(expr, self.shell.user_ns))
              self.temporary_objects.add(result)
              new_line += [line[pos:m.start()], result.name()]
              pos = expr_end
          return ' '.join(new_line)
  
      def transform(self, line, continue_prompt):
          r'''
          Evaluates *line* in :attr:`shell.interface` and returns a
          string representing the result of that evaluation.
  
          :param line: the line to be transformed *and evaluated*
          :type line: string
          :param continue_prompt: is this line a continuation in a sequence of multiline input?
          :type continue_prompt: bool
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import interface_shell_embed, InterfaceShellTransformer
              sage: shell = interface_shell_embed(maxima)
              sage: ift = InterfaceShellTransformer(shell=shell, config=shell.config, prefilter_manager=shell.prefilter_manager)
              sage: ift.transform('2+2', False)   # note: output contains triple quotation marks
              'sage.misc.all.logstr(r"""4""")'
              sage: ift.shell.ex('a = 4')
              sage: ift.transform(r'sage(a)+4', False)
              'sage.misc.all.logstr(r"""8""")'
              sage: ift.temporary_objects
              set()
              sage: shell = interface_shell_embed(gap)
              sage: ift = InterfaceShellTransformer(shell=shell, config=shell.config, prefilter_manager=shell.prefilter_manager)
              sage: ift.transform('2+2', False)
              'sage.misc.all.logstr(r"""4""")'
  
          TESTS:
  
          Check that whitespace is not stripped and that special characters are
          escaped (:trac:`28439`)::
  
              sage: shell = interface_shell_embed(gap)
              sage: ift = InterfaceShellTransformer(shell=shell, config=shell.config, prefilter_manager=shell.prefilter_manager)
              sage: ift.transform(r'Print("  -\n\\\\-  ");', False)
              'sage.misc.all.logstr(r"""  -\n\\\\-""")'
  
              sage: shell = interface_shell_embed(macaulay2)  # optional - macaulay2
              sage: ift = InterfaceShellTransformer(shell=shell, config=shell.config, prefilter_manager=shell.prefilter_manager) # optional - macaulay2
              sage: ift.transform('net(ZZ^2)', False)  # optional - macaulay2
              'sage.misc.all.logstr(r"""  2\nZZ""")'
          '''
          line = self.preparse_imports_from_sage(line)
  
          try:
              t = self.shell.interface.eval(line)
          finally:
              # Once we've evaluated the lines, we can clear the
              # temporary objects
              self.temporary_objects = set()
          # We do not strip whitespace from t here as the individual interface is
          # responsible for that
          return 'sage.misc.all.logstr(r"""%s""")' % t
  
  
  def interface_shell_embed(interface):
      """
      Returns an IPython shell which uses a Sage interface on the
      backend to perform the evaluations.  It uses
      :class:`InterfaceShellTransformer` to transform the input into the
      appropriate ``interface.eval(...)`` input.
  
      INPUT:
  
      - ``interface`` -- A Sage ``PExpect`` interface instance.
  
      EXAMPLES::
  
          sage: from sage.repl.interpreter import interface_shell_embed
          sage: shell = interface_shell_embed(gap)
          sage: shell.run_cell('List( [1..10], IsPrime )')
          [ false, true, true, false, true, false, true, false, false, false ]
          <ExecutionResult object at ..., execution_count=None error_before_exec=None error_in_exec=None ...result=[ false, true, true, false, true, false, true, false, false, false ]>
      """
      cfg = sage_ipython_config.copy()
      ipshell = InteractiveShellEmbed(config=cfg,
                                      banner1='\n  --> Switching to %s <--\n\n' % interface,
                                      exit_msg='\n  --> Exiting back to Sage <--\n')
      ipshell.interface = interface
      ipshell.prompts = InterfacePrompts(interface.name())
  
      while ipshell.prefilter_manager.transformers:
          ipshell.prefilter_manager.transformers.pop()
      while ipshell.prefilter_manager.checkers:
          ipshell.prefilter_manager.checkers.pop()
      ipshell.ex('import sage.misc.all')
  
      InterfaceShellTransformer(shell=ipshell,
                                prefilter_manager=ipshell.prefilter_manager,
                                config=cfg)
      return ipshell
  
  
  def get_test_shell():
      """
      Return a IPython shell that can be used in testing the functions
      in this module.
  
      OUTPUT:
  
      An IPython shell
  
      EXAMPLES::
  
          sage: from sage.repl.interpreter import get_test_shell
          sage: shell = get_test_shell(); shell
          <sage.repl.interpreter.SageTestShell object at 0x...>
          sage: shell.parent.shell_class
          <class 'sage.repl.interpreter.SageTestShell'>
          sage: shell.parent.test_shell
          True
          sage: shell.quit()
  
      TESTS:
  
      Check that :trac:`14070` has been resolved::
  
          sage: from sage.tests.cmdline import test_executable
          sage: cmd = 'from sage.repl.interpreter import get_test_shell; shell = get_test_shell()'
          sage: (out, err, ret) = test_executable(["sage", "-c", cmd])
          sage: out + err
          ''
      """
      config = sage_ipython_config.default()
      config.TerminalIPythonApp.test_shell = True
      config.TerminalIPythonApp.shell_class = SageTestShell
      app = SageTerminalApp.instance(config=config)
      if app.shell is None:
          app.initialize(argv=[])
      else:
          try:
              app.shell._restart()
          except AttributeError:
              pass
      # No quit noise
      app.shell.verbose_quit = False
      return app.shell
  
  
  #######################
  # IPython TerminalApp #
  #######################
  
  class SageCrashHandler(IPAppCrashHandler):
      def __init__(self, app):
          """
          A custom :class:`CrashHandler` which gives the user
          instructions on how to post the problem to sage-support.
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import SageTerminalApp, SageCrashHandler
              sage: app = SageTerminalApp.instance()
              sage: sch = SageCrashHandler(app); sch
              <sage.repl.interpreter.SageCrashHandler object at 0x...>
              sage: sorted(sch.info.items())
              [('app_name', u'Sage'),
               ('bug_tracker', 'http://trac.sagemath.org'),
               ('contact_email', 'sage-support@googlegroups.com'),
               ('contact_name', 'sage-support'),
               ('crash_report_fname', u'Crash_report_Sage.txt')]
          """
          contact_name = 'sage-support'
          contact_email = 'sage-support@googlegroups.com'
          bug_tracker = 'http://trac.sagemath.org'
          CrashHandler.__init__(self,
              app, contact_name, contact_email, bug_tracker, show_crash_traceback=True)
          self.crash_report_fname = 'Sage_crash_report.txt'
  
  
  class SageTerminalApp(TerminalIPythonApp):
      name = u'Sage'
      crash_handler_class = SageCrashHandler
  
      test_shell = Bool(False, help='Whether the shell is a test shell')
      test_shell.tag(config=True)
      shell_class = Type(InteractiveShell, help='Type of the shell')
      shell_class.tag(config=True)
  
      def load_config_file(self, *args, **kwds):
          r"""
          Merges a config file with the default sage config.
  
          .. note::
  
              This code is based on :meth:`Application.update_config`.
  
          TESTS:
  
          Test that :trac:`15972` has been fixed::
  
              sage: from sage.misc.temporary_file import tmp_dir
              sage: from sage.repl.interpreter import SageTerminalApp
              sage: d = tmp_dir()
              sage: from IPython.paths import get_ipython_dir
              sage: IPYTHONDIR = get_ipython_dir()
              sage: os.environ['IPYTHONDIR'] = d
              sage: SageTerminalApp().load_config_file()
              sage: os.environ['IPYTHONDIR'] = IPYTHONDIR
          """
          super(SageTerminalApp, self).load_config_file(*args, **kwds)
          newconfig = sage_ipython_config.default()
          # merge in the config loaded from file
          newconfig.merge(self.config)
          self.config = newconfig
  
      def init_shell(self):
          r"""
          Initialize the :class:`SageInteractiveShell` instance.
  
          .. note::
  
              This code is based on
              :meth:`TerminalIPythonApp.init_shell`.
  
          EXAMPLES::
  
              sage: from sage.repl.interpreter import SageTerminalApp
              sage: app = SageTerminalApp.instance()
              sage: app.shell
              <sage.repl.interpreter.SageTestShell object at 0x...>
          """
          # Shell initialization
          self.shell = self.shell_class.instance(
              parent=self,
              config=self.config,
              profile_dir=self.profile_dir,
              ipython_dir=self.ipython_dir)
          self.shell.configurables.append(self)
          self.shell.has_sage_extensions = SAGE_EXTENSION in self.extensions
  
          # Load the %lprun extension if available
          try:
              import line_profiler
              assert line_profiler  # silence pyflakes
          except ImportError:
              pass
          else:
              self.extensions.append('line_profiler')
  
          if self.shell.has_sage_extensions:
              self.extensions.remove(SAGE_EXTENSION)
  
              # load sage extension here to get a crash if
              # something is wrong with the sage library
              self.shell.extension_manager.load_extension(SAGE_EXTENSION)
  