Sage’s IPython Modifications

This module contains all of Sage’s customizations to the IPython interpreter. These changes consist of the following major components:

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 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 SageCrashHandler to give the user instructions on how to report the crash to the Sage support mailing list.

SageInteractiveShell

The 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

The SageInteractiveShell provides the following customizations:

  • Modify the libraries before calling system commands. See system_raw().

SageTerminalInteractiveShell

The SageTerminalInteractiveShell is a close relative of 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 interface_shell_embed() takes a 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 InterfaceShellTransformer.

class sage.repl.interpreter.InterfaceShellTransformer(*args, **kwds)

Bases: IPython.core.prefilter.PrefilterTransformer

Initialize this class. All of the arguments get passed to PrefilterTransformer.__init__().

temporary_objects

a list of hold onto interface objects and keep them from being garbage collected

EXAMPLES:

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)')
['a', 'b']
preparse_imports_from_sage(line)

Finds occurrences of strings such as sage(object) in line, converts object to shell.interface, and replaces those strings with their identifier in the new system. This also works with strings such as maxima(object) if shell.interface is maxima.

Parameters:line (string) – the line to transform

Warning

This does not parse nested parentheses correctly. Thus, lines like sage(a.foo()) will not work correctly. This can’t be done in generality with regular expressions.

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)')
'2 +  sage1 '
sage: ift.preparse_imports_from_sage('2 + gap(a)')
'2 + gap(a)'
transform(line, continue_prompt)

Evaluates line in shell.interface and returns a string representing the result of that evaluation.

Parameters:
  • line (string) – the line to be transformed and evaluated
  • continue_prompt (bool) – is this line a continuation in a sequence of multiline input?

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("""4""")'
sage: ift.shell.ex('a = 4')
sage: ift.transform(r'sage(a)+4', False)
'sage.misc.all.logstr("""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("""4""")'
class sage.repl.interpreter.SageCrashHandler(app)

Bases: IPython.terminal.ipapp.IPAppCrashHandler

A custom 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')]
class sage.repl.interpreter.SageInteractiveShell(ipython_dir=None, profile_dir=None, user_module=None, user_ns=None, custom_exceptions=((), None), **kwargs)

Bases: sage.repl.interpreter.SageNativeExecute, IPython.core.interactiveshell.InteractiveShell

class sage.repl.interpreter.SageNativeExecute

Bases: object

x.__init__(...) initializes x; see help(type(x)) for signature

system_raw(cmd)

Run a system command.

If the command is not a sage-specific binary, adjust the library paths before calling system commands. See trac ticket #975 for a discussion of running system commands.

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('env | grep "^LD_LIBRARY_PATH=" | grep $SAGE_LOCAL')
sage: shell.user_ns['_exit_code']
1
sage: shell.system_raw('R --version')
R version ...
sage: shell.user_ns['_exit_code']
0
sage.repl.interpreter.SagePreparseTransformer(**kwargs)

EXAMPLES:

sage: from sage.repl.interpreter import SagePreparseTransformer
sage: spt = SagePreparseTransformer()
sage: spt.push('1+1r+2.3^2.3r')
"Integer(1)+1+RealNumber('2.3')**2.3"
sage: preparser(False)
sage: spt.push('2.3^2')
'2.3^2'

TESTS:

Check that syntax errors in the preparser do not crash IPython, see trac ticket #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 ']'
sage.repl.interpreter.SagePromptTransformer(**kwargs)

Strip the sage:/....: prompts of Sage.

EXAMPLES:

sage: from sage.repl.interpreter import SagePromptTransformer
sage: spt = SagePromptTransformer()
sage: spt.push("sage: 2 + 2")
'2 + 2'
sage: spt.push('')
''
sage: spt.push("....: 2+2")
'2+2'

This should strip multiple prompts: see trac ticket #16297:

sage: spt.push("sage:   sage: 2+2")
'2+2'
sage: spt.push("   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.push("   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 ticket #16196 is resolved:

sage: shell.run_cell('    sage: 1+1')
2
class sage.repl.interpreter.SageTerminalApp(**kwargs)

Bases: IPython.terminal.ipapp.TerminalIPythonApp

crash_handler_class

alias of SageCrashHandler

init_shell()

Initialize the SageInteractiveShell instance.

Note

This code is based on TerminalIPythonApp.init_shell().

EXAMPLES:

sage: from sage.repl.interpreter import SageTerminalApp, DEFAULT_SAGE_CONFIG
sage: app = SageTerminalApp(config=DEFAULT_SAGE_CONFIG)
sage: app.initialize(argv=[])  # indirect doctest
sage: app.shell
<sage.repl.interpreter.SageTerminalInteractiveShell object at 0x...>
load_config_file(*args, **kwds)

Merges a config file with the default sage config.

Note

This code is based on Application.update_config().

TESTS:

Test that trac ticket #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: IPYTHONDIR = os.environ['IPYTHONDIR']
sage: os.environ['IPYTHONDIR'] = d
sage: SageTerminalApp().load_config_file()
sage: os.environ['IPYTHONDIR'] = IPYTHONDIR
class sage.repl.interpreter.SageTerminalInteractiveShell(config=None, ipython_dir=None, profile_dir=None, user_ns=None, user_module=None, custom_exceptions=((), None), usage=None, banner1=None, banner2=None, display_banner=None, **kwargs)

Bases: sage.repl.interpreter.SageNativeExecute, IPython.terminal.interactiveshell.TerminalInteractiveShell

sage.repl.interpreter.embedded()

Returns True if Sage is being run from the notebook.

EXAMPLES:

sage: from sage.repl.interpreter import embedded
sage: embedded()
False
sage.repl.interpreter.get_test_shell()

Returns a IPython shell that can be used in testing the functions in this module.

Returns:an IPython shell

EXAMPLES:

sage: from sage.repl.interpreter import get_test_shell
sage: shell = get_test_shell(); shell
<sage.repl.interpreter.SageTerminalInteractiveShell object at 0x...>

TESTS:

Check that trac ticket #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
''
sage.repl.interpreter.interface_shell_embed(interface)

Returns an IPython shell which uses a Sage interface on the backend to perform the evaluations. It uses 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 ]
sage.repl.interpreter.preparser(on=True)

Turn on or off the Sage preparser.

Parameters:on (bool) – if True turn on preparsing; if False, turn it off.

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

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